Disease Control Newsletter- Annual summary of communicable diseases, 2021

Disease Control Newsletter

Volume 49, Number 1 (pages 1-28) 2023

Annual Summary of Communicable Diseases Reported to the

Minnesota Department of Health, 2021

Introduction

Assessment of the population’s health is a core public health function.

Surveillance for communicable diseases is one type of assessment.

Epidemiologic surveillance is the systematic collection, analysis, and

dissemination of health data for the planning, implementation, and evaluation

of health programs. The Minnesota Department of Health (MDH) collects

information on infectious diseases for the purposes of determining disease

impact, assessing trends in disease occurrence, characterizing affected

populations, prioritizing control efforts, and evaluating prevention strategies.

Prompt reporting allows outbreaks to be recognized in a timely fashion when

control measures are most likely to be effective in preventing additional cases.

In Minnesota, communicable disease reporting is centralized, whereby reporting

sources submit standardized reports to MDH. Cases of disease are reported

pursuant to Minnesota Rules Governing Communicable Diseases (Minnesota

Rules 4605.7000 -4605.7800). The diseases listed in Table 1 must be reported

to MDH. As stated in the rules, physicians, health care facilities, laboratories,

veterinarians, and others are required to report these diseases. Reporting

sources may designate an individual within an institution to perform routine

reporting duties (e.g., an infection preventionist for a hospital).

Since April 1995, MDH has participated as an Emerging Infections Program

(EIP) site funded by the U.S. Centers for Disease Control and Prevention (CDC)

and, through this program, has implemented active hospital- and laboratory-

based surveillance for several conditions, including selected bacterial diseases,

foodborne diseases, tickborne diseases, and hospitalized influenza cases.

Isolates of pathogens from certain diseases are required to be submitted to

MDH (Table 1: Minnesota Rules Governing Communicable Diseases (Minnesota

Rules 4605.7000-4605.7800). The MDH Public Health Laboratory (PHL)

performs microbiologic and molecular evaluation of isolates, such as pulsed-

field gel electrophoresis (PFGE) and whole genome sequencing (WGS), to

determine whether isolates (e.g., enteric pathogens such as Salmonella and

Escherichia coli O157:H7) are related and potentially associated with a common

source. Testing of submitted isolates also allows detection and monitoring of

antimicrobial resistance.

Table 2 summarizes cases of selected communicable diseases reported during

2021 by district of the patient’s residence. Pertinent observations for some

of these diseases are presented below. Incidence rates in this report were

calculated using disease-specific numerator data collected by MDH and a

standardized set of denominator data derived from U.S. Census data. Disease

incidence is categorized as occurring within the seven-county Twin Cities

metropolitan area (metropolitan area) or outside of it in Greater Minnesota

(unless otherwise indicated).

Due to the COVID-19 pandemic, data collection was eliminated or greatly

delayed for some diseases.

Anaplasmosis

Anaplasmosis is a rickettsial disease

caused by the bacteria Anaplasma

phagocytophilum, which is transmitted

by bites from Ixodes scapularis,

the blacklegged tick. Although the

organism that causes anaplasmosis

has been known by other names and

was once thought to be a part of the

genus Ehrlichia, anaplasmosis and

ehrlichiosis are distinct diseases caused

by different rickettsial species. The same

tick vector also transmits the etiologic

agents of Lyme disease, babesiosis,

ehrlichiosis (due to E. muris), and

Powassan virus. In rare circumstances, A.

phagocytophilum may be transmitted by

blood transfusion.

In 2021, 603 confirmed and probable

cases of anaplasmosis (10.5 cases per

100,000) were reported, up from the 407

cases reported in 2019. Although case

numbers were a bit lower the last few

years, the 2021 total is more in keeping

with the trend we saw through the mid-

2010s. A median of 613 cases per year

have reported since 2010 (Figure 1). In

2021, 382 (63%) confirmed and probable

cases reported were male. The median

age for cases was 64 years (range, 1 to

96), 19 years older than the median age

of confirmed Lyme disease cases, but

close to the median age of confirmed or

probable babesiosis cases (69 years). As

is typical, most cases had illness onsets

during the summer months, with 66%

of cases reporting illness onsets in May,

June, or July. This timing is consistent

with exposures occurring during the

typical peak season for blacklegged

tick activity in Minnesota. In 2021, 173

(29%) cases were hospitalized for their

anaplasmosis infection, with a median

duration of 4 days (range, 1 to 44

days). Forty-seven (8%) cases reported

complications (e.g., organ failure) due to

anaplasmosis infection.

continued on page 4

DCN 48;1 2022

Note: check website for updates

Table 1. Diseases Reportable to the Minnesota Department of Health

DCN 48;1 2022

Table 2. Cases of Selected Communicable Diseases Reported to the Minnesota

Department of Health by District of Residence, 2021

District

(population per U.S. Census 2020 estimates)

Disease

Total

Metropolitan

(3,130,769)

Central

(779.498)

Southwestern

(214,402)

South Central

(292,503)

Southeastern

(512,691)

West Central

(244,473)

Northwestern

(159,468)

Northeastern

(323,538)

Unknown

Residence

Anaplasmosis 603 144 140 1 9 52 45 97 115 0

Babesiosis 63 13 14 0 2 9 5 10 10 0

Blastomycosis 82 25 12 1 3 14 1 8 18 0

Botulism (Infant) 1 1 0 0 0 0 0 0 0 0

Brucellosis 19 18 0 0 0 0 1 0 0 0

Campylobacteriosis 1192 570 182 100 89 161 38 19 33 0

Cryptosporidiosis 373 86 53 33 51 88 40 7 15 0

Cyclosporiasis 66 21 3 15 4 11 4 0 8 0

Escherichia coli O157 infection 69 32 7 1 4 0 7 8 10 0

Hemolytic uremic syndrome 11 3 3 1 0 3 1 0 0 0

Giardiasis

388 184 36 28 28 27 21 9 55 0

Haemophilus influenzae disease 56 21 10 4 6 2 7 3 3 0

Histoplasmosis 190 84 21 14 23 19 21 3 5 0

HIV (non-AIDS) 245 184 25 7 3 10 8 2 6 0

AIDS (diagnosed in 2020) 81 64 6 2 0 7 0 0 2 0

Legionnaires’ disease 130 79 9 6 10 13 1 1 11 0

Listeriosis 12 9 1 0 0 0 1 0 1 0

Lyme disease 1033 458 232 9 14 113 33 44 130 0

Measles (rubeola) 0 0 0 0 0 0 0 0 0 0

Mumps 0 0 0 0 0 0 0 0 0 0

Pertussis 29 20 2 1 0 1 1 0 4 0

Q Fever (acute) 5 1 2 0 0 1 1 0 0 0

Q Fever (chronic)

1 0

0 0 1 0 0 0 0 0

Salmonellosis 853 448 118 63 54 64 41 25 39 1

Sexually transmitted diseases 33709 22910 3196 741 973 1994 1143 681 1579 465

Chlamydia trachomatis - genital infections 22578 14729 2329 585 758 1495 810 455 1075 315

Gonorrhea 9671 7141 749 143 176 453 291 143 425 150

Syphilis, total 1460 1040 118 13 39 46 42 83 79 0

Primary/Secondary 565 419 40 2 12 15 16 22 39 0

Early non-Primary non-Secondary* 415 303 30 1 7 13 10 33 18 0

Unknown Duration or Late** 466 309 48 10 20 18 15 24 22 0

Congenital 14 9 0 0 0 0 1 4 0 0

Other*** n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Shigellosis n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Streptococcal invasive disease - Group A

214 118 24 2

1 16 15 16 22 0

Streptococcal invasive disease - Group B 584 293 97 16 36 54 29 16 43 0

Streptococcus pneumoniae disease 309 138 58 15 21 22 16 10 29 0

Toxoplasmosis 7 5 0 0 0 2 0 0 0 0

Tuberculosis 134 102 8 9 4 6 2 2 1 0

Tularemia 1 0 0 0 0 0 0 1 0 0

Varicella 169 97 22 5 11 9 14 1 10 0

Viral hepatitis A 12 10 1 1 0 0 0 0 0 0

Viral hepatitis B (acute infections only) 10 6 0 0 1 2 1 0 0 0

Viral hepatitis C (acute infections only) 66 50 3 1 0 1 5 3 3 0

West Nile virus disease 36 28 1 1 2 0 2 2 0 0

* Duration ≤1 year

** Duration >1 year

*** Includes unstaged neurosyphilis, latent syphilis of unknown duration, and latent syphilis with clinical manifestations

County Distribution within Districts

Metropolitan - Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, Washington

Central - Benton, Cass, Chisago, Crow Wing, Isanti, Kanabec, Mille Lacs, Morrison, Pine, Sherburne, Stearns, Todd, Wadena, Wright

Southwestern - Big Stone, Chippewa, Cottonwood, Jackson, Kandiyohi, Lac Qui Parle, Lincoln, Lyon, Murray, Nobles, Pipestone, Redwood, Renville, Rock, Swift, Yellow

Medicine

South Central - Blue Earth, Brown, Faribault, Le Sueur, McLeod, Martin, Meeker, Nicollet, Sibley, Waseca, Watonwan

Southeastern - Dodge, Fillmore, Freeborn, Goodhue, Houston, Mower, Olmsted, Rice, Steele, Wabasha, Winona

West Central - Becker, Clay, Douglas, Grant, Mahnomen, Norman, Otter Tail, Pope, Stevens, Traverse, Wilkin

Northwestern - Beltrami, Clearwater, Hubbard, Kittson, Lake of the Woods, Marshall, Pennington, Polk, Red Lake, Roseau

Northeastern - Aitkin, Carlton, Cook, Itasca, Koochiching, Lake, St. Louis

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2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

Number of Cases

Year of Report

Lyme disease

Anaplasmosis

Babesiosis

Figure 1. Reported I. scapularis-borne Disease Cases in Minnesota by Year of Report

Arboviral Diseases

Endemic Mosquitoborne

Arboviral Diseases

Historically, the primary arboviral

encephalitides found in Minnesota

have been La Crosse encephalitis,

Western equine encephalitis (WEE),

and West Nile virus (WNV) encephalitis,

but in recent years other viruses like

Jamestown Canyon have emerged as

significant causes of disease. While

WNV and WEE are maintained in

mosquito-to-bird transmission cycles

involving several different species of

each, La Crosse and Jamestown Canyon

viruses use mammals instead of birds as

part of their transmission cycles. WNV

is established throughout Minnesota,

and will probably be present in the state

to some extent every year, whereas

human cases of other diseases may

occur more sporadically. Interpreting

the effect of weather on arboviral

transmission is complex, making it

difficult to predict the number of

people who will become infected in any

given year.

In 2021, Minnesota reported 36 WNV

disease cases and 19 asymptomatic

blood donors. Of the reported cases, 27

(75%) had neuroinvasive presentations

including encephalitis or meningitis,

while the remaining nine had West

Nile fever. None of the cases died. Fifty

percent (18) of the cases were male,

and the median age of all cases was

62 years old (range, 10 to 82). Thirty

(83%) cases were hospitalized, with a

median stay of 9 days (range, 2 to 40).

The majority of cases, 92%, reported

symptom onset in August or September.

Although cases are reported from

across Minnesota, risks for human

WNV infection continue to be higher in

central and western Minnesota where

the primary mosquito vector, Culex

tarsalis, is most abundant.

In 2021, there were no reported cases

of La Crosse encephalitis in Minnesota,

which is consistent with the trend

of fewer cases in the last few years.

The disease, which primarily affects

children, is transmitted through the bite

of infected Aedes triseriatus (Eastern

Tree Hole) mosquitoes and is

maintained in a cycle that includes

mosquitoes and small mammals.

Exposure to infected mosquitoes

typically occurs in wooded or shaded

areas inhabited by this species,

especially in areas where water-holding

containers (e.g., waste tires, buckets,

or cans) that provide breeding habitats

are abundant. Since 1985, 145 cases

have been reported from 22 Minnesota

counties, primarily in the southeastern

part of the state. Many people who are

infected have no apparent symptoms,

but severe disease is more common

in children. Most people report an

illness onset during the typical arboviral

season from mid-July through mid-

September.

In 2021, six cases of Jamestown Canyon

virus disease, a California group virus

related to La Crosse, were reported.

The virus is transmitted by Aedes

mosquitoes, and the maintenance cycle

in nature is thought to include deer and

other large mammals. Much remains

unknown about the clinical spectrum

of Jamestown Canyon virus, but the

typical presentation includes fever,

and in more severe cases, meningitis

or encephalitis. The virus is likely

widespread in Minnesota. Cases were

aged 34 to 74 years, with a median of

42 years, and all but one of the cases

were male. Four cases (67%) presented

with neuroinvasive disease, including

meningitis and encephalitis, and three

of the cases were residents of counties

in northeastern Minnesota. Due to

the mosquito vectors involved in the

transmission cycle for this virus, disease

onsets can occur from late spring

through the early part of the fall.

Endemic Tickborne

Arboviral Disease

Powassan virus (POW) is a tickborne

flavivirus that includes a strain (lineage

II or “deer tick virus”) that is transmitted

by Ixodes scapularis. Based on

findings from routine tick surveillance

activities, the virus appears to be

widely distributed in the same wooded

parts of the state that are endemic to

other pathogens transmitted by the

blacklegged tick. The virus can cause

encephalitis or meningitis, and long-

term sequelae occur in approximately

half of those patients. Approximately

10-15% of cases are fatal. Since the first

case in 2008, there have been cases

every year except for 2014 and 2015,

with a peak of 11 cases in 2011 (range, 1

to 11). Five cases of POW were reported

in 2021. All five cases were male in

2021, and ages ranged from 44 to 75

years. All the cases in 2021 had disease

that progressed to severe illness with

meningitis or encephalitis, and two

cases died. Similar to other tickborne

diseases, the majority of patients

report being exposed to ticks in north

central Minnesota. Interestingly, four

of the cases experienced illness onset

in October, with the other patient first

experiencing symptoms in June.

DCN 48;1 2022

continued...

Average Annual Incidence of

Histoplasmosis, Minnesota, 2017-2021,

(n=872)

Average Annual Incidence of

Blastomycosis, Minnesota, 1999-2021,

(n=915)

Note the difference in geographical distribution of Minnesota’s endemic fungal diseases, blastomycosis and histoplasmosis.

Blastomycosis occurs more frequently in northern and northeastern counties, and histoplasmosis occurs more often in western and

southern counties. While clinicians should test for both diseases when clinical illness is consistent with a fungal infection, these maps

may trigger questions about travel or otherwise help assess risk.

Babesiosis

Babesiosis is a malaria-like illness

caused by a protozoan parasite,

typically Babesia microti, which

infects red blood cells. B. microti is

transmitted to humans by bites

from Ixodes scapularis (the

blacklegged tick), the same vector

that transmits the agents of Lyme

disease, anaplasmosis, one form of

ehrlichiosis, and a strain of Powassan

virus. Babesia parasites can also be

transmitted by blood transfusion.

Although most people infected

with Babesia have asymptomatic

infections, people with weak immune

systems, other co-morbidities, and

the elderly can become seriously ill.

In 2021, there were 63 confirmed and

probable cases reported (1.1 cases

per 100,000), a slight increase from

the 55 cases in 2019. Over the past

decade, slight annual fluctuations in

reported cases have been observed,

however, reported case numbers

continue to trend upward (range, 41

to 72) and are consistently higher

than annual cases reported in the

previous decade, 2000-2010 (range,

1 to 56) (Figure 1). In recent years,

case demographics were similar. In

2021, 37 (59%) of the cases occurred

in males. The median case age was

69 years (range, 2 to 92), up slightly

from 67 in 2019, and older than the

median ages for both anaplasmosis

(64 years) and Lyme disease (45

years). Illness onset dates peaked

in the summer months: 44 (80%)

of the 55 cases with known onset

date reported first experiencing

symptoms in June, July, or August.

Twenty (32%) cases were hospitalized

due to their infection in 2021 with

a median admission duration of 6

days (range, 2 to 18). Seven patients

reported severe complications (e.g.,

organ failure), and one patient with

complications died as a result of their

babesiosis infection.

Blastomycosis

Blastomycosis is an infection caused

by a fungus called Blastomyces. In

2021, 82 blastomycosis cases were

reported. This continues an increase

in cases reported in the past 5 years,

with a median of 79 cases/year from

2017 to 2021 compared to a median

of 33 cases/year for the prior 18

years.

The median age of blastomycosis

cases in 2021 was 56.5 years (range,

8 to 89 years), and 51 (62%) were

male. In 2021, cases were more

likely to be older and female than

in previous years. Of the 77 cases

for whom race and ethnicity was

reported, 63 (82%) cases were white,

6 (8%) were American Indian/Alaska

Native, 5 (7%) were Asian, 1 (1%) was

Black/African American, and 2 were

of another race. One case (1%) was

Hispanic.

Figure 2. Comparison of Average Annual Incidence

of Endemic Fungal Diseases in Minnesota

DCN 48;1 2022

When hospitalization status was

known, 54 of 80 (68%) cases

were hospitalized, for a median

of 8 days (range, 1 to 54 days).

Nineteen (23%) cases died, which

is a significantly higher case fatality

rate (CFR) than the 10% mean CFR

during 1999-2020. Blastomycosis

was the listed cause of death for

12 cases, 3 cases had other causes

of death listed, and the cause of

death was unknown for 4 cases.

When it was possible to identify

the body system infected by

Blastomyces, 51 (64%) cases had a

pulmonary-only infection, 22 (27%)

had a disseminated infection, and

7 (9%) had an extra-pulmonary

infection.

There were two blastomycosis

outbreaks identified in 2021.

One case was part of an ongoing

outbreak associated with a family

cabin property in Pine County.

This outbreak began in 2019 and

resulted in 4 cases through 2021.

A second outbreak-related case

was exposed at a dam worksite in

Wisconsin; the other case in that

outbreak was a Wisconsin resident.

From 1999 to 2021, 916 cases

of blastomycosis in Minnesota

residents were reported. Exposure

information is available for 662

cases. The largest number, 138

(21%), were likely exposed in St.

Louis County. Eighty (12%) cases

were likely exposed in Itasca

County, 61 (9%) in Cass County, 24

(4%) in Hennepin County, and 20

(3%) in Beltrami County. Seventy-

six cases (11%) were exposed in

Wisconsin.

In 2021, the statewide incidence

was 1.4 cases/100,000 population,

compared to a 1999-2020

median annual incidence of 0.63

cases/100,000. A map of average

annual incidence of blastomycosis

from 1999 to 2021 clearly shows

the highly endemic regions,

which include the northern

and northeastern counties of

Minnesota (Figure 2). This is in

contrast to the other endemic

fungal disease found in Minnesota,

histoplasmosis, which has higher

incidence levels in southern and

western counties. While clinicians

should test for both diseases when

clinical illness is consistent with

a fungal infection, these maps

may help assess differential risk in

various regions of the state.

Botulism

Botulinum toxin, a neurotoxin, is

produced by the spore-forming

bacteria Clostridium botulinum and

other related Clostridium species.

There are 8 distinct toxin types:

A, B, C, D, E, F, G, and H. Toxin

types A, B, E, F, and H can cause

human intoxication. Botulism is

characterized by a descending,

bilateral paralysis that can be fatal

without treatment. Botulism spores

are ubiquitous in the environment

and cause three main forms of

intoxication: foodborne, wound, and

intestinal toxemia, which includes

infant botulism and intestinal

toxemia. Infant botulism, which is

the most common form in the United

States, results from the ingestion of

C. botulinum spores that germinate

into vegetative bacteria that colonize

the intestinal tract, producing toxin

that is absorbed into the circulation.

In 2021, one infant botulism and

one intestinal toxemia botulism case

were reported. The infant botulism

case occurred in a 21-week-old

male. He received botulism immune

globulin (BabyBIG) and recovered.

The disease was caused by toxin type

B. The intestinal colonization case

occurred in a 10-year-old female

with a medical history including

short bowel syndrome, G-tube

dependence, and D-lactic acidosis.

Despite receiving heptavalent

botulism antitoxin, she succumbed

to the disease. Her illness was

caused by toxin type A.

From 2001 to2021, 16 cases

of infant botulism, 2 cases of

foodborne botulism, 2 cases of

intestinal toxemia botulism, and

1 case of possible iatrogenic

botulism were identified among

Minnesota residents. The median

age of affected infants was 21 weeks

(range, 5 to 41 weeks). Twelve (75%)

infant botulism cases were caused by

botulinum toxin type B and 4 (25%)

by toxin type A. Thirteen infants

were known to be hospitalized, for

a median of 15 days (range, 8 to 30

days); one infant did not require

hospitalization. The 2 foodborne

cases, caused by toxin type A

occurred in 2009 in two men who

consumed home-canned asparagus.

Both cases were hospitalized, for

6 and 16 days. No deaths occurred

among the infant or foodborne

botulism cases.

Brucellosis

Brucellosis is an acute or chronic

illness caused by bacteria of

the Brucella genus. There are 5

important species of Brucella: B.

abortus, B. melitensis, B. suis, B.

canis, and B. ovis, of which cattle,

goats, pigs, dogs, and sheep are

the respective reservoir animals.

Transmission can occur through

ingestion of unpasteurized dairy

products, contact with infected

animal tissue, or inhalation of

aerosolized bacteria in a laboratory

setting. Minnesota’s livestock have

been brucellosis free since 1985.

Most infections are acquired in

Brucella-endemic countries.

In 2021, 19 confirmed cases were

reported. Eleven of these cases were

part of an outbreak of brucellosis

linked to unpasteurized queso

fresco, a homemade soft cheese,

likely made with goat milk, imported

from Mexico by a private seller and

distributed in the Twin Cities. The

eleven cases tested positive for

Brucella melitensis and B. melitensis

was isolated from a sample of the

cheese. The median age of outbreak

cases was 44 years (range, 16-52

years), 7 (64%) were male, and all

were Hispanic. Ten (91%) cases

were hospitalized for a median of 7

days (range, 1-13 days). Some cases

experienced severe complications,

including endocarditis (n=3), sepsis

(n=2), splenomegaly (n=1), and

hepatitis (n=1).

Of the eight sporadic cases, four

were exposed in Somalia, one in

Ethiopia, one in Russia, and one

who ate boar meat from Oklahoma.

One case had an unknown exposure

location. The median age of sporadic

cases was 44 (range, 14-76); 5(63%)

were female. Complications of

brucellosis among sporadic cases

included three (38%) cases who

experienced osteomyelitis and

three (38%) with sepsis. All 2021

brucellosis cases survived their

infection.

From 2007 to 2021, 46 confirmed

cases were reported. Thirty likely

acquired their infection outside

the United States, and 16 were

domestically acquired. The median

number of cases reported annually

was 2 (range, 0 to 19). Thirty-six

were infected with B. melitensis,

seven with B. suis, two with B.

DCN 48;1 2022

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2013 2014 2015 2016 2017 2018 2019 2020 2021

Number of Cases

Year of Report

Campylobacter

Salmonella

Cyclospora

STEC

Shigella

Campylobacter, 1041

Salmonella, 853

STEC, 317

Shigella, 133

Cyclospora, 24

Median

abortus, and one with an unidentified

Brucella species diagnosed by

serology only. The median age of

cases was 47 years (range, 3 to 86).

Twenty of the 42 cases for which race

was known were black, 18 were white

(of which 11 identified as Hispanic),

and four were Asian/Pacific Islander.

Campylobacteriosis

During 2021, 1,562 Campylobacter

cases were reported. Of those,

1,192 were culture-confirmed, and

370 were only tested by a culture-

independent diagnostic test (CIDT)

and not subsequently culture-

confirmed. The rate of culture-

confirmed Campylobacter cases

reported in 2021 was 20.9 per

100,000 population. The 1,192

culture-confirmed Campylobacter

cases represent a 50% increase from

the 793 cases reported in 2020, and a

22% increase from the annual median

of 975 cases reported from 2011 to

2020 (range, 793 to 1,238). In 2021,

48% of cases occurred in people who

resided in the metropolitan area. Of

the 1,104 Campylobacter isolates

confirmed and identified to species

by MDH, 85% were C. jejuni and 9%

were C. coli.

The median age of culture-confirmed

cases was 41 years (range, 2 months

to 99 years). Thirty-eight percent

were between 20 and 49 years of age,

and 11% were ≤5 years of age. Fifty-

four percent were male. Seventeen

percent were hospitalized; the median

length of hospitalization was 3 days.

Two (0.2%) cases died. Forty-nine

percent of infections occurred during

June through September. Of the 982

cases for whom data were available,

62 (6%) reported travel outside the

United States during the week prior to

illness onset. The most common travel

destination was Mexico (n=21).

In 2009, a CIDT became commercially

available for the qualitative detection

of Campylobacter antigens in stool.

In 2021, 40 patients were positive

for Campylobacter by an antigen

detection CIDT conducted in a

clinical laboratory. However, only

19 (48%) of the specimens were

subsequently culture-confirmed.

Beginning In 2015, some clinical

laboratories in Minnesota began

testing stool specimens with PCR-

based gastrointestinal pathogen

panels, another type of CIDT. In

2021, 1,353 patients were positive

for Campylobacter by a PCR

gastrointestinal panel; 1,005 (74%)

of these specimens were culture-

confirmed. The median age of the

CIDT-positive only cases was 49 years

(range, 1 month to 93 years). Sixty-

eight (18%) cases were hospitalized;

the median hospital stay was 3 days

(range, 1 to 123 days). No CIDT-only

cases died.

Four outbreaks of Campylobacter

infections were identified in 2021.

Nineteen cases were associated with

poultry contact at a farm and garden

center, 13 cases were associated

with person-to-person transmission

among men who have sex with men

(MSM) contact, two cases were

associated with chicken liver yakitori

at a restaurant, and two cases were

associated with multiple food items

at a restaurant.

A primary feature of

public health importance

among Campylobacter cases

was the continued presence

of Campylobacter isolates resistant

to fluoroquinolone antibiotics (e.g.,

ciprofloxacin), which are commonly

used to treat campylobacteriosis.

In 2021, the overall proportion

of ciprofloxacin resistance

among Campylobacter isolates tested

was 26%. However, historically, 80-

90% of Campylobacter isolates from

patients with a history of foreign

travel during the week prior to illness

onset, regardless of destination,

were resistant to fluoroquinolones

as compared to approximately 20%

of Campylobacter isolates from

patients who acquired their infection

domestically.

Figure 3. Number of Selected Enteric Pathogen Cases by Year of Report, 2013-2021

DCN 48;1 2022

Candidemia

In 2017, surveillance began for

candidemia among residents of the

metropolitan area. Candidemia is a

bloodstream infection caused by the

Candida fungal species and is one of

the most common types of healthcare-

associated bloodstream infections

in the United States. Risk factors

include prolonged hospitalization in

an intensive care unit, having a central

venous catheter, a weakened immune

system, recent surgery (especially

abdominal surgery), recently receipt of

antibiotics, total parenteral nutrition,

kidney failure, hemodialysis, and

diabetes.

In 2021, 160 cases were reported

among residents of the metropolitan

area. The overall incidence rate was 5.2

per 100,000, and the highest county-

level incidence was in Ramsey County

(7.0 per 100,000). The median age

was 59 years (range, newborn to 97

years). Seventy-seven cases (48%) were

male; 108 (69%) were white, 27 (17%)

were black, 11 (7%) were Asian/Pacific

Islander, and race was unknown for 8

cases.

Of the 160 cases, 99% were

hospitalized at time of diagnosis, and

45 (29%) died while hospitalized.

Underlying conditions included

malignancy (29%), chronic lung

condition (28%), diabetes (39%), renal

disease (28%), neurologic condition

(36%), skin condition (16%), and

chronic liver disease (11%). Healthcare

risk factors included receiving systemic

antibiotics in the 14 days prior to

diagnosis (83%); presence of a central

venous catheter in the 2 days prior

to diagnosis (67%); being admitted to

the ICU within 14 days prior to or 14

days after diagnosis (50%); and having

surgery in the 90 days before diagnosis

(23%).

More than 17 different Candida

species are known to be agents of

human infection; however, the two

most common species comprised over

50% of candidemia infections. Of the

160 cases, 38% were C. albicans, 37%

C. glabrata, 10% C. parapsilosis, 3%

C. tropicalis, 3% C. dubliniensis, 1%

C. kefyr, 1% C. krusei, and 3% with

other species including C. nivariensis,

C. guilliermondii, and C. lusitaniae.

Six cases (4%) were co-infected with

multiple species of Candida at the time

of incident specimen collection.

As primarily a healthcare-associated

infection, injection drug use (IDU) has

not been considered a common risk

factor for candidemia. However, with

the increasing opioid epidemic, IDU

has been reported as an increasingly

common condition associated with

candidemia. In 2017, only 2/143 (1.4%)

cases had IDU documented in their

medical chart. However, in 2018, 15

(11%) cases, in 2019, 16 (10%) cases,

in 2020, 13 (7%) cases, and in 2021,

14 (9%) cases had IDU documented

in their medical chart. MDH began

collecting additional information

regarding IDU in 2019 to monitor the

changing trends in IDU and candidemia

epidemiology.

Carbapenem-resistant

Enterobacteriaceae(CRE),

Acinetobacter baumannii

(CRA), and Pseudomonas

aeruginosa(CRPA)

Carbapenem-

resistant Enterobacterales (CRE),

Acinetobacter baumannii (CRAB),

and Pseudomonas aeruginosa

(CRPA) are gram-negative bacilli

that most commonly occur among

patients with significant healthcare

exposures, co-morbid conditions,

invasive devices, and those who

have received extended courses of

antibiotics. Invasive infections caused

by CRE, such as carbapenem-resistant

Klebsiella pneumoniae, are associated

with higher morbidity and mortality

than those caused by carbapenem-

susceptible Enterobacterales. CRAB

is increasingly recognized as one of

the leading causes of healthcare-

associated infections worldwide and

is associated with high mortality rates

and unfavorable clinical outcomes.

Invasive infections caused by CRPA

are associated with higher morbidity

and mortality than those caused

by carbapenem-susceptible P.

aeruginosa.

Carbapenem resistance can

be acquired through a variety

of mechanisms including

transmissible genetic elements.

Some CRE, CRAB, and CRPA carry

resistance genes that produce

enzymes called carbapenemases.

Certain carbapenemases (e.g., K.

pneumoniae carbapenemase

[KPC]) can easily spread between

bacteria of similar species

KPC is

the predominant carbapenemase

in the United States while other

carbapenemases (e.g., New Delhi

metallo-β-lactamase [NDM], Verona

integron-encoded metallo-β-

lactamase [VIM], and oxacillinase-48

[OXA-48]) are more frequently

identified in other countries.

Resistance can also be acquired

through the production of a

β-lactamase effective against third

generation cephalosporins (e.g., AmpC

β-lactamases or extended-spectrum

β-lactamases [ESBLs]) when combined

with porin mutations that prevent

carbapenem antibiotics from entering

the cell.

MDH first identified a KPC-

producing CRE in February 2009,

and began voluntary reporting,

including isolate submission,

for all Enterobacterales and A.

baumannii resistant to imipenem,

meropenem, doripenem, or

ertapenem using current Clinical and

Laboratory Standards Institute (CLSI)

breakpoints (ertapenem excluded

for A. baumannii isolates). In 2012,

MDH used standardized CRE and

CRAB definitions developed by the

Emerging Infections Program (EIP)

Multi-site Gram-negative Surveillance

Initiative (MuGSI) and initiated active

laboratory- and population-based

surveillance in Hennepin and Ramsey

Counties. As a subset of statewide

reporting, MuGSI surveillance includes

all isolates from normally sterile

sites or urine of the three most

common types of CRE (Escherichia

coli, Enterobacter spp.,

or Klebsiella spp

) and A. baumannii.

A MuGSI incident case is defined as

the first eligible isolate of each species

collected from a Hennepin or Ramsey

County resident in 30 days.

In 2016, MDH initiated statewide CRE

surveillance for E. coli, Enterobacter

spp., Klebsiella spp

, and Citrobacter

spp.; MDH also tracks other

Enterobacterales including, but not

limited to, Morganella spp., Proteus

spp., and Providencia spp. The MDH

Public Health Laboratory (PHL) tests

all CRE isolates for carbapenemase

production using a phenotypic assay

(modified carbapenem inactivation

method [mCIM] or CarbaNP) and

conducts PCR on isolates with a

positive phenotypic test for KPC,

NDM, OXA-48-like, VIM, and IMP

genes. All CRAB isolates are tested by

PCR for KPC, NDM, OXA-48, VIM, and

IMP genes, along with Acinetobacter-

specific OXA genes (OXA-23, OXA-24,

and OXA-58).

DCN 48;1 2022

continued...

In 2017, the Centers for Disease

Control and Prevention (CDC) released

Interim Guidance for a Public Health

Response to Contain Novel or Targeted

Multidrug-resistant Organisms

(MDROs) for state and local public

health departments responding to

cases of novel or targeted MDROs,

including carbapenemase-producing

organisms (CPO). Novel or targeted

MDROs are epidemiologically

important because these organisms

cause severe, difficult-to-treat

infections and have the potential to

spread within healthcare settings.

MDH utilizes the Containment Strategy

in response to all single cases of

carbapenemase-producing CRE, CRAB,

and CRPA in Minnesota. This rapid

and comprehensive action includes

prompt identification of the organism,

notification and investigation with

healthcare facilities, and response or

“containing the spread” to slow the

spread of novel or targeted MDROs in

Minnesota.

In 2021, 479 CRE incident cases

representing 439 patients were

identified from clinical cultures among

Minnesota residents; median age

was 73 years (range, <1 to 99) and

265 (60%) identified as female. The

most common organism for incident

cases was Enterobacter spp. (183)

followed by Klebsiella spp. (98) and

E. coli (94). Other CRE organisms

included Serratia spp. (30), Proteus

spp. (26), Citrobacter spp. (24),

Providencia spp. (16), Morganella

spp. (2), and other Enterobacterales

(6). Among 479 incident cases, there

were 127 CRE MuGSI incident cases

(representing 112 patients) reported

among residents of Hennepin and

Ramsey Counties. Fifty-eight (46%)

isolates were Enterobacter spp., 40

(31%) were E. coli, and 29 (23%)

were Klebsiella spp. with 12 isolates

demonstrating carbapenemase

production (five NDM, five OXA-48-

like, and two KPC). CRE MuGSI incident

cases were most frequently isolated

from urine (117) followed by blood (7)

and other sterile sites (3).

Among 479 CRE incident cases, 43

(9%) were carbapenemase-producing

organisms. Twenty cases (from 18

patients) were KPC positive (E. cloacae

[7], K. pneumoniae [7], K. oxytoca [4],

C. freundii [1], and Hafnia alvei [1]),

nine cases (from 5 patients) were NDM

positive (E. coli [8] and P. mirabilis [1]),

nine cases (from 8 patients) were IMP

positive (P. rettgeri [6], P. mirabilis

[1], M. morganii [1], and E. cloacae

[1]), and five cases (from 4 patients)

were OXA-48 positive (K. pneumoniae

[4] and E. coli [1]). Urine (27) was the

most common isolate source followed

by blood (5), sputum (5), other non-

sterile sites (2), wound (2), bone (1),

and peritoneal fluid (1). We identified

seven additional CRE surveillance cases

(from 7 patients) through colonization

screening harboring NDM (3), KPC (2),

OXA-48 (1), and NDM & OXA-48 dual

mechanism (1). Among surveillance

cases with known organism, there

was one isolate each of E. coli, K.

pneumoniae, and E. cloacae. Among

35 Minnesota residents infected with

carbapenemase-producing CRE, the

median age was 68 years (range, 32 to

89) and 18 (51%) identified as female.

There were cases in 18 counties; 13

(37%) were residents of Hennepin

or Ramsey Counties, six (17%) were

residents of other counties within

the Twin Cities metro area, and the

remaining 16 (46%) were residents

of 12 different counties in greater

Minnesota.

In 2021, 18 CRAB incident cases

representing 14 patients were

identified from clinical cultures among

Minnesota residents. Among these 14

patients, the median age was 53 years

(range, 1 to 85) and 8 (62%) identified

as male. Wound (8) was the most

common isolate source followed by

urine (6), sputum (3), and tissue (1).

Of 18 CRAB incident cases, eight cases

were reported for MuGSI isolated from

wound (4), urine (3), and sputum (1).

Three CRAB incident isolates (from

two patients) possessed genes for

carbapenemase production both of

which were OXA-23.

Active laboratory- and population-

based surveillance for CRPA was

initiated on August 1, 2016 in

Hennepin and Ramsey Counties as

part of MuGSI and ended on July

31, 2018. This surveillance included

all CRPA isolates collected from

normally sterile sites, wounds, urine,

sputum, throat cultures from cystic

fibrosis (CF) patients, or other lower

respiratory sites that are resistant to

imipenem, meropenem, or doripenem

using current CLSI breakpoints. An

incident case was defined as the

first report of CRPA, or a subsequent

report of CRPA ≥ 30 days after the last

incident report. Despite surveillance

discontinuation in 2018, PHL continues

to test any submitted CRPA isolates

for carbapenemase production. In

2021, five CRPA isolates demonstrated

carbapenemase production (4 KPC

and 1 NDM). The CRPA isolates

harboring KPC carbapenemase were

part of an outbreak associated with a

contaminated endoscope.

Clostridioides difficile

Clostridioides difficile is an anaerobic,

spore-forming, Gram-positive bacillus

that produces two pathogenic toxins:

A and B. C. difficile infections (CDI)

range in severity from mild diarrhea

to fulminant colitis and death.

Transmission of C. difficile occurs

primarily in healthcare facilities,

where environmental contamination

by C. difficile spores and exposure to

antimicrobial drugs are common. The

primary risk factor for development

of CDI in healthcare settings is recent

use of antimicrobials, particularly

clindamycin, cephalosporins, and

fluoroquinolones. Other risk factors

for CDI acquisition in these settings

are age >65 years, severe underlying

illness, intensive care unit admission,

nasogastric intubation, and longer

duration of hospital stay.

In the early 2000s, a marked increase

in the number of CDI cases and

mortality due to CDI was noted

across the United States, Canada, and

England. Most notable was a series of

large-scale outbreaks in Quebec first

reported in March 2003. During this

period, Quebec hospitals reported a

5-fold increase in healthcare-acquired

CDI. These and other healthcare

facility (e.g., long-term care facilities)

outbreaks have been associated with

the emergence of a more virulent

strain of C. difficile, designated

North American PFGE type 1 (NAP1),

toxinotype III.

In 2009, in an effort to better

understand the burden of CDI in

Minnesota, the MDH Emerging

Infection Program (EIP) initiated

population-based, sentinel surveillance

for CDI at clinical laboratories serving

Stearns, Benton, Morrison, and Todd

Counties; in 2012 Olmsted County

was added. CDIs that occur outside

the traditional healthcare settings

(i.e., community-associated) have also

been receiving increased attention.

Community-associated (CA) CDI data

from 2009-2011 across 10 EIP sites

showed that 64% of CA CDI patients

received prior antibiotics, and 82% had

some outpatient healthcare exposure.

A CDI case is defined as a positive C.

difficile toxin assay on an incident stool

specimen from a resident (≥ 1 year of

age) of one of the five counties. A CDI

DCN 48;1 2022

case is classified as healthcare facility-

onset (HCFO) if the initial specimen

was collected >3 days after admission

to a healthcare facility. Community-

onset (CO) cases who had an overnight

stay at a healthcare facility in the 12

weeks prior to the initial specimen

are classified as CO-HCFA, whereas CO

cases without documented overnight

stay in a healthcare facility in the 12

weeks prior to the initial specimen

result are classified as CA. A more

detailed set of case definitions is

available upon request.

In 2021, 808 incident cases of CDI

were reported in the five sentinel

counties (192 per 100,000 population),

an increase from 180 per 100,000

population in 2020. Sixty-one percent

of these cases were classified as CA,

22% as CO-HCFA, and 16% as HCFO.

The median ages for CA, CO-HCFA, and

HCFO cases were 58 years, 64 years,

and 70 years, respectively. Forty-nine

percent of CA cases were prescribed

antibiotics in the 12 weeks prior to

stool specimen collection compared

to 86% of HCFO cases and 88% of

CO-HCFA cases. Due to the COVID-19

pandemic, interviews were only

conducted on putative CA cases after

July 1, 2021. 227 putative CA cases

prior to that date were not contacted

for interview. Of the remaining 268

putative CA cases eligible for interview,

155 were interviewed and confirmed

as CA cases. Forty-seven percent of CA

cases reported antibiotic use in the 12

weeks prior to illness onset date. Most

common uses of antibiotics included

treatment of ear, sinus, or upper

respiratory infections (28%); urinary

tract infections (24%); and dental

procedures (22%).

Cryptosporidiosis

During 2021, 429 cases of

cryptosporidiosis were reported. Of

those, 56 were positive only on a

rapid antigen screening test and were

considered probable cases.

The 373 confirmed cases of

cryptosporidiosis (6.6 per 100,000

population) in 2021 is similar to the

median number of confirmed cases

reported annually from 2013 to 2020

(median, 353 cases; range, 224 to

439). The median age of confirmed

cases in 2021 was 26 years (range,

9 months to 85 years). Children 10

years of age or younger accounted for

25% of cases. Sixty-one percent were

female. Of the 353 cases for which

race was reported, 305 (86%) were

white, 28 (8%) were Black, 6 (2%) were

Asian American, 1 (<1%) was American

Indian, and 13 (4%) reported being

other or multiple races. Fourteen (4%)

were Hispanic. Sixty percent of cases

occurred from July through October.

The incidence of cryptosporidiosis in

the South Central, Southeastern, West

Central, and Southwestern districts

(17.5, 17.4, 16.5, and 15.2 cases per

100,000, respectively) was significantly

higher than the statewide incidence.

Only 86 (23%) cases occurred among

residents of the metropolitan area (2.7

per 100,000). Fifty-four (15%) cases

required hospitalization, for a median

of 2 days. Two deaths were reported.

Three confirmed outbreaks of

cryptosporidiosis were identified in

Minnesota in 2021, accounting for

17 cases (5 laboratory-confirmed).

All were due to person-to-person

transmission in childcare settings.

Two of these outbreaks occurred in

Hennepin County and one in Dodge

County. In addition, 4 laboratory-

confirmed cases were part of an

outbreak that occurred at a hotel

waterpark in South Dakota.

Cyclosporiasis

There were 66 Cyclospora cases

reported in 2021 (1.17 per 100,000

population). This is markedly higher

than the median number of cases

reported from 2011 to 2020 (median,

4.5; range, 0 to 156 per year). In 2021,

32% of cases occurred in people who

resided in the metropolitan area.

The median age of cases was 52.5

years (range, 6 to 84 years). Fifty-

five percent were female. Of the 63

cases where race was reported, 56

(89%) were white, 2 (3%) were Black,

and 5 (8%) were Other race. Seven

(11%) were Hispanic. Six percent

were hospitalized; the median length

of hospitalization was 4 days (range,

2 to 7 days). Eighty-two percent of

infections occurred from May through

July. Of the 34 non-outbreak cases for

whom data were available, 7 (21%)

reported travel outside the United

States during the 2 weeks prior to

illness onset.

Two foodborne outbreaks of

cyclosporiasis were identified in

Minnesota in 2021. The first was

a multi-state outbreak associated

with pre-packaged romaine lettuce,

accounting for 22 laboratory-confirmed

Minnesota cases. The second was

a multi-state outbreak associated

with butter lettuce, accounting for 2

laboratory-confirmed Minnesota cases.

Escherichia coli O157 Infection,

Other Shiga Toxin-producing

E. coli, and Hemolytic Uremic

Syndrome (HUS)

During 2021, 584 Shiga toxin-

producing Escherichia coli (STEC) cases

were reported. Of those, 69 were

culture-confirmed E. coli O157, 263

were culture-confirmed non-O157

STEC, and 252 were only positive by a

culture-independent test (CIDT) and

not subsequently culture-confirmed.

The 69 culture-confirmed cases

of E. coli O157 infection (1.22 per

100,000 population) reported in 2021

represents a 42% decrease from the

median number of culture-confirmed

cases reported annually from 2011 to

2020 (median, 119 cases; range, 65

to 146). During 2021, 32 (46%) cases

occurred in the metropolitan area.

Fifty-five (80%) cases occurred during

May through October. The median

age of the cases was 17 years (range,

11 months to 79 years). Twenty-nine

percent of the cases were 4 years of

age or younger. Twenty-four (35%)

cases were hospitalized; the median

hospital stay was 3 days (range, 1 to 31

days). No cases died.

The 263 culture-confirmed non-O157

cases (4.65 per 100,000 population)

reported in 2021 represents a 53%

increase from the median number

of culture-confirmed cases reported

annually from 2011 to 2020 (median,

172 cases; range, 105 to 322). E. coli

O103 was the serogroup for 42 (17%)

cases, E. coli O26 for 34 (17%), E. coli

O111 for 33 (13%), E. coli O145 for 19

(4%), E. coli O121 for 15 (5%), and E.

coli O45 for 6 (2%). The median age

of the non-O157 STEC cases was 31

years (range, 4 months to 96 years).

Fifty (19%) cases were hospitalized;

the median hospital stay was 3 days

(range, 1 to 32 days). No cases died.

During 2021, 252 cases were reported

with specimens that were positive by a

CIDT conducted at a clinical laboratory,

but were not subsequently culture-

confirmed. CIDTs have become widely

adopted by clinical laboratories for the

detection of Shiga toxin or Shiga toxin

genes in stool. The median age of the

CIDT-positive only cases was 41 years

DCN 48;1 2022

continued...

(range, 4 months to 97 years). Seventy

(27%) cases were hospitalized; the

median hospital stay was 3 days

(range, 1 to 56 days). Two cases died.

Two E. coli O157 outbreaks were

identified during 2021. One outbreak

was due to animal contact, and

the other was due to foodborne

transmission. In August, an outbreak

of E. coli O157 infections was likely

associated with indirect contact

with a calf and sheep at a private

home; three cases, all laboratory-

confirmed, were identified. Two

cases developed hemolytic uremic

syndrome (HUS), but none of the

cases died. In November, a national

outbreak of E. coli O157 infections

was associated with spinach. Two

cases were identified in Minnesota,

both laboratory-confirmed. Neither

developed HUS nor died.

Four non-O157 STEC outbreaks

were identified during 2021. One

outbreak was due to person-to-

person transmission in a childcare

setting, one was due to foodborne

transmission, one was due to

animal contact, and one had an

unknown transmission route. In July,

an outbreak of E. coli O103:H11

infections associated with person-

to-person transmission occurred at

a childcare facility in Polk County.

Nineteen cases, one laboratory-

confirmed, were identified. No

cases developed HUS nor died.

In August, an outbreak of E. coli

O145:H28 infections with an unknown

transmission route was identified.

Three cases, all laboratory-confirmed,

were identified. No cases developed

HUS nor died.In October, an outbreak

of E. coli O111:H8 infections was

associated with contact with calves

at an apple orchard. Two cases, both

laboratory-confirmed, were identified.

Neither case developed HUS nor died.

In December, a national outbreak

of E. coli O121:H19 infections was

associated with romaine lettuce. Two

cases were identified in Minnesota.

Neither developed HUS nor died.

Hemolytic Uremic Syndrome

(HUS)

In 2021, 11 HUS cases were reported.

The number of reported cases is

the same as the median number of

cases reported annually from 2011

to 2020 (median, 11 cases; range, 3

to 17). In 2021, the median age of

HUS cases was 2 years (range, 1 to 11

years). All 11 cases were hospitalized,

with a median hospital stay of 13

days (range, 1 to 31 days). No cases

died. From 1997 through 2021, the

overall case fatality rate among HUS

cases was 5.1%. E. coli O157:H7 was

cultured from the stool of 7 (64%)

cases. E. coli O5:H9 was cultured

from the stool of one case and E.

coli O-genotype untypeable:H8 was

cultured from the stool of one case.

Two cases were Shiga toxin positive

by PCR but not culture-confirmed.

In 2021, there were two outbreak-

associated HUS cases.

Giardiasis

During 2021, 388 cases of Giardia

infection (6.9 per 100,000 population)

were reported. This represents a 38%

decrease from the median number

of cases reported annually from 2011

through 2020 (median, 629.5 cases;

range, 416 to 692). Recent immigrants

and refugees accounted for 6% of

cases. An additional 8% of cases

reported international travel in the 3

weeks prior to illness onset. Excluding

recent immigrants and refugees,

the median age of cases was 39

years (range, 5 months to 94 years).

Eighteen percent of cases were less

than 10 years of age, and 38% were

more than 50 years of age. Fifty-six

percent of non-immigrant and refugee

cases were male. Giardia infections

had a summer/fall seasonality; 47%

of non-immigrant and refugee cases

occurred during July through October.

Twenty-eight (7%) cases required

hospitalization, for a median of 4 days

(range, 2 to 17 days). No outbreaks of

giardiasis were identified.

Haemophilus influenzae

Fifty-six Haemophilus

influenzae disease cases (1.0 per

100,000 population) were reported

in 2021. Cases ranged in age from

newborn to 95 years (median 64

years). Allowing for more than one

syndrome per case, 26 (46%) cases

had pneumonia, 5 (9%) bacteremia,

8 (14%) septic shock, 13 (23%)

meningitis, 2 (4%) osteomyelitis, 3

(5%) empyema, and the following

each had 1 (2%): cellulitis, abscess,

septic arthritis, otitis media,

epiglottitis. Eight (14%) cases died.

Of 45 H. influenzae isolates for which

typing was performed, 12 were type

a, 2 type b (Hib), 1 type e, 3 type f,

and 27 were nontypeable. There were

2 Hib disease cases in 2021 compared

to 1 case in 2020, 3 in 2019, 1 in 2018,

2 in 2017, 5 in 2016, and 2 in 2015.

Among the 2021 Hib disease cases,

one was a 2-year old child who had

meningitis and survived; this child had

not received any Hib vaccination. The

second was in a 6-month old who had

meningitis and survived; this child had

documentation of one dose of Hib

vaccine.

The eight deaths occurred in patients

ranging in age from 56 to 92 years.

Three decedents had pneumonia,

two had septic shock, two had

pneumonia and septic shock, and one

had pneumonia, meningitis and septic

shock. Co-morbidities were reported

in seven patients and serotypes

were nontypeable (5) or type f (1);

two isolates were not available for

serotyping.

Histoplasmosis

Histoplasmosis is caused by the

soil-dwelling dimorphic fungus

Histoplasma capsulatum. Infection

typically results from inhalation of

aerosolized spores, and symptomatic

infections usually involve pulmonary

disease, though disseminated or non-

pulmonary infections are possible.

Common activities associated with

exposure include farming, exposure to

soil enriched with bird or bat guano,

remodeling or demolition of old

buildings, and clearing trees or brush

in which birds have roosted.

In 2021, there were 38 confirmed and

152 probable cases of histoplasmosis

reported. These numbers are

consistent with the case counts from

the years prior to the COVID-19

pandemic.

The median age of cases was 48 years

(range, 0 to 88 years), and 112 (59%)

were male. Of the 133 cases for whom

race was reported, 112 (84%) were

white, 11 (8%) were Black, 6 (5%)

were Asian, 2 (1.5%) were American

Indian/Alaska Native, 1 (<1%) was

Native Hawaiian/Pacific Islander and

1 (<1%) was more than one race.

Of the 130 for whom ethnicity was

reported, 4 (3%) were Hispanic.

When hospitalization status was

reported, 38 of 70 (54%) cases were

hospitalized. Median hospitalization

duration was 5 days (range, 1 to 47

days). There were 2 deaths among

the 54 cases for which outcome was

DCN 48;1 2022

2000

4000

6000

8000

10000

12000

100

150

200

250

300

350

400

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

Number of People Living with HIV/AIDS

Year

HIV Disease Diagnoses*

All Deaths**

Living with HIV/AIDS

*Includes all new cases of HIV infection (both HIV [non-AIDS] and AIDS at first diagnosis) diagnosed within a given calendar year.

**Deaths in Minnesota among people with HIV/AIDS, regardless of location of diagnosis and cause.

Number of New HIV/AIDS Cases and Deaths

reported, a case fatality rate of 4%.

Histoplasmosis was the primary cause

of death for both of those cases.

From 2017 to 2021, 872 cases of

histoplasmosis were reported. The

annual incidence of histoplasmosis

in Minnesota in 2021 was 3.3 cases

per 100,000 population, similar to

the average annual incidence of 3.0

cases per 100,000 for 2017-2020.

The average annual incidence of

histoplasmosis by county shows

that cases occur more frequently

in southern and western counties

(Figure 2). This is in contrast to the

other endemic fungal disease found in

Minnesota, blastomycosis, for which

the highly endemic region includes the

northern and northeastern counties of

Minnesota. While clinicians should test

for both diseases when clinical illness

is consistent with a fungal infection,

these maps may help assess possible

risks in different parts of the state.

HIV Infection and AIDS

HIV/AIDS incidence in Minnesota

remains moderately low. The most

state-specific recent rate data is from

2020, which shows that state-specific

HIV infection rates ranged from

1.5 per 100,000 population in

Montana to 22.1 per 100,000 in

Georgia. Minnesota had the 14th

lowest rate (4.8 cases per 100,000

population).

As of December 31, 2021, a

cumulative total of 12,643 cases

of HIV infection (2,418 AIDS at

first diagnosis, and 10,225 HIV

[non-AIDS] cases) were reported

among Minnesota residents. By the

end of 2021, an estimated 9,696

persons with HIV/AIDS were living

in Minnesota.

The annual number of AIDS cases

reported in Minnesota increased

steadily from 1982 through the

early 1990s, reaching a peak of 361

cases in 1992. Beginning in 1996,

the annual number of new AIDS

diagnoses and deaths declined

sharply, primarily due to better

antiretroviral therapies. In 2021, 81

new AIDS cases (Figure 4) and 99

deaths among persons living with

HIV infection in Minnesota were

reported.

The number of HIV (non-AIDS)

diagnoses has varied over the past

decade. There was a peak of 278

newly diagnosed HIV (non-AIDS)

cases in 2009, and a low of 183

new HIV (non-AIDS) cases reported

in 2020. Before 2020, the lowest

number of cases reported was 215

new HIV (non-AIDS) cases, reported

in 2017.

In 2021, 74% (222/298) of new HIV

diagnoses (both HIV [non-AIDS] and

AIDS at first diagnosis) occurred in

the metropolitan area. In Greater

Minnesota there were 76 cases in

29 of 80 counties. HIV infection is

most common in areas with higher

population densities and greater

poverty.

The majority of new HIV infections

in Minnesota occur among males.

Trends in the annual number of new

HIV infections diagnosed among

males differ by race/ethnicity. New

infections occurred primarily among

white males in the 1980s and early

1990s. Whites still comprise the

largest number of HIV infections

among males, but the proportion of

cases accounted for by white males

account is decreasing. In 2021,

there were 87 new infections among

white males, which is 37% of new

HIV infections among males. Among

black African American males, there

Figure 4. HIV/AIDS: Number of New Cases, Prevalent Cases, and Deaths by Year

DCN 48;1 2022

continued...

were 68 new HIV diagnoses in 2021,

which is about a third of new HIV

infections among males (29%).

Among Hispanic males of any race

and black African-born males, there

were 41 and 21 new HIV infections

in 2021, respectively.

Females account for an increasing

percentage of new HIV infections,

from 11% of new infections in

1990 to 21% in 2021. Trends in

HIV infections diagnosed annually

among females also differ by race/

ethnicity. Early in the epidemic,

whites accounted for the majority

of newly diagnosed infections.

Since 1991, the number of new

infections among women of color

has exceeded that of white women.

In 2021, women of color accounted

for 73% of new HIV infections

among females in Minnesota.

The number of diagnoses among

African-born women has been

increasing over the past decade.

In 2021, the number of new cases

among African-born women was

25, accounting for 39% of all new

diagnoses among women. In

2021, there were 10 cases (16%)

diagnosed among African American

women.

Despite relatively small numbers

of cases, HIV/AIDS affects persons

of color disproportionately in

Minnesota. In 2021, men of color

comprised approximately 17% of

the male population in Minnesota

and 61% of new HIV diagnoses

among men. Similarly, persons of

color comprised approximately

17% of the female population

in Minnesota and 73% of new

HIV infections among women. It

bears noting the use of race can

be a proxy for other risk factors,

including lower socioeconomic

status and education. Race is not

considered a biological cause of

disparities in the occurrence of HIV.

Historically, race/ethnicity data

for HIV/AIDS in Minnesota have

grouped non-African born blacks

and black African-born persons

together as “black.” In 2001, MDH

began analyzing these groups

separately, and a marked trend of

increasing numbers of new HIV

infections among black African-born

persons was observed. In 2021,

there were 46 new HIV infections

reported among black Africans.

While black African-born persons

comprise about 2% of the state’s

population, they accounted for 15%

of all HIV infections diagnosed in

Minnesota in 2021.

In 2021, there were 88 diagnosed

with HIV less than 30 years of age,

accounting for 34% of all cases.

Most of the cases were among

young males, where 87% of cases

were less than 30 years of age.

Since the beginning of the

epidemic, male-to-male sex (men

who have sex with men; MSM)

has been the predominant mode

of exposure to HIV reported

in Minnesota. In 2021, MSM

(including MSM who also inject

drugs) accounted for 53% of new

diagnoses among men. IDU was

the predominant mode of exposure

for women (of those with known

exposure).

In the fall of 2019, an outbreak was

declared among persons who inject

drugs (PWID) diagnosed with HIV

in Minnesota. Statewide there was

a two-fold increase among PWID

with 11 cases in 2018 increasing to

22 cases in 2019. The outbreak area

included residents of Hennepin and

Ramsey counties, where an alert

was indicated among PWID. At the

end of 2020, the outbreak included

101 cases. Persons likely to be at

high risk for HIV infection include

sex partners or syringe-sharing

partners of people known to be

living with HIV, PWID and their

sex partners and needle sharing

partners, persons who exchange

sex for income or other items they

need, and persons who experienced

or are currently experiencing

homelessness.

In the fall of 2020, an alert for the

Duluth area was indicated among

newly diagnosed HIV infections,

after which an outbreak was

declared in March 2021. There

were 23 cases associated with

the outbreak between September

2019 and the beginning of 2021.

Typically, there are from one to

five cases of HIV per year in St.

Louis County. The health alert also

indicated a rise in the number

of syphilis cases in the Duluth

area. Both declared outbreaks are

currently on-going.

HIV perinatal transmission in the

United States decreased 90%

since the early 1990s. The trend

in Minnesota has been similar.

While the number of births to HIV-

infected women increased nearly

7-fold between 1990 and 2019,

with 60 births to pregnant persons

in 2021, the rate of perinatal

transmission decreased, from 15%

in 1994-1996 to 0% over the last 4

years (2018-2021), with the last HIV-

positive Minnesota birth in 2017.

Influenza

Several influenza surveillance

methods are employed. Data are

summarized by influenza season

(generally October-April) rather than

calendar year.

Hospitalized Cases

Surveillance for pediatric (<18

years of age) laboratory-confirmed

hospitalized cases of influenza

in the metropolitan area was

established during the 2003-2004

influenza season and expanded to

include adults for the 2005-2006

influenza season. For the 2008-

2009 season surveillance was

expanded statewide. Since the

2013-2014 season, clinicians have

been encouraged to collect a throat

or nasopharyngeal swab, or other

specimen from all patients admitted

to a hospital with suspect influenza

and submit the specimen to the

Public Health Lab (PHL) for influenza

testing. For the 2014-2015 season,

influenza B subtyping was added.

During the 2020-2021 influenza

season (October 1, 2020 – April 30,

2021), there were 35 laboratory-

confirmed hospitalized cases

reported. This represents a rate of

0.62 cases per 100,000 persons,

compared to 71.3 cases per 100,000

in 2019-2020 and 44.6 cases per

100,000 in 2018-2019. Cases

included 11 influenza A (all unknown

A type) and 24 influenza B (all

unknown lineage). Among the cases,

9% were 0-18, 17% were 19-49, 14%

were 50-64, and 60% were 65 years

of age and older. Median age was 69

years. Residents of the metropolitan

area made up 57% of cases.

Case report forms have been

completed on 100% of the 20

metropolitan area cases that were

selected for review. Of these, 28%

were diagnosed with pneumonia,

17% required admission into an

intensive care unit, and 11% were

placed on mechanical ventilation. An

invasive bacterial co-infection was

present in 22% of hospitalized cases.

DCN 48;1 2022

Antiviral treatment was prescribed for

67% of cases. Overall, 82% of adult

and 0% of pediatric cases had at least

one chronic medical condition that

would have put them at increased risk

for influenza disease.

Pediatric Deaths

There were 0 pediatric influenza-

associated deaths during this season.

Laboratory Data

The Minnesota Laboratory System

(MLS) Laboratory Influenza Surveillance

Program is made up of more than 110

clinic- and hospital-based laboratories

which voluntarily submit testing data

on a weekly basis. These laboratories

perform rapid testing for influenza and

respiratory syncytial virus. Significantly

fewer laboratories perform viral culture

testing. Some laboratories perform

PCR testing for influenza, and others

also perform PCR testing for other

respiratory viruses. The PHL provides

further characterization of submitted

influenza isolates to determine the

hemagglutinin serotype. Tracking

laboratory results assists healthcare

providers with patient diagnosis of

influenza-like illness (ILI) and provides

an indicator of the progression of the

influenza season, as well as prevalence

of disease in the community. Between

October 4, 2020–May 22, 2021,

laboratories reported data on 54,981

influenza molecular tests, 24 (<1%) of

which were positive for influenza. Of

these, 0 were positive for influenza A

(H3), 0 were positive for influenza A

(H1N1)pdm09, 10 (42%) were positive

for influenza A-not subtyped, and 14

(58%) were positive for influenza B.

Sentinel Surveillance

We conduct sentinel surveillance for

ILI (fever >100° F, and cough, and/or

sore throat in the absence of known

cause other than influenza) through

outpatient medical providers, including

those in private practice, public health

clinics, urgent care centers, emergency

rooms, and university student health

centers. There were 85 sites in 39

counties. Participating providers report

the total number of patient visits each

week and number of patient visits

for ILI by age group (0-4 years, 5-24

years, 25-64 years, ≥65 years). The

percentage of ILI peaked during the

week October 4-10, 2020, at 0.9%.

Influenza Incidence Surveillance

MDH continued to participate in

Optional Influenza Surveillance

Enhancements during the 2020-2021

influenza season. Each week, nine

clinic sites reported the number of ILI

patients divided by the total patients

seen by the following age groups: 0-4

years, 5-24 years, 25-49 years, 50-64

years, and ≥65 years. Clinical specimens

were collected on the first 10 patients

with acute respiratory illness for PCR

testing performed by the PHL for

influenza, SARS-CoV-2, and 13 other

respiratory pathogens.

Minimal demographic information

and clinical data were provided with

each specimen. From October 4,

2020–May 22, 2021, these clinics saw

1,777 ILI patients. They submitted 984

specimens for influenza testing; none

were positive for influenza.

ILI Outbreaks in Schools and Long-

term Care Facilities

Since 2009, schools report outbreaks

when the number of students absent

with ILI reaches 5% of total enrollment,

or when three or more students with ILI

were absent from the same elementary

classroom. Six schools in 3 counties

reported ILI outbreaks during the

2020-2021 school year. The number of

schools reporting ILI outbreaks since

the 2009-2010 school year ranged from

a low of 6 in 2020-2021 to a high of

1,302 in 2009-2010.

An influenza outbreak is suspected in a

long-term care facility (LTCF) when two

or more residents in a facility develop

symptoms consistent with influenza

during a 48- to 72-hour period. An

influenza outbreak is confirmed when

at least one resident has a positive

culture, PCR, or rapid antigen test for

influenza and there are other cases

of respiratory illness in the same unit.

Six facilities in 5 counties reported

confirmed outbreaks during the 2020-

2021 influenza season. The number of

LTCFs reporting outbreaks ranged from

a low of three in 2008- 2009 to a high

of 212 in 2017-2018.

Legionnaires' Disease

In 2021, 130 confirmed cases of

Legionnaires’ disease (2.3 per 100,000

population) were reported. This is

a 38% increase from the 94 cases

reported in 2020 and a 13% increase

from the median number of cases

reported annually from 2016 to 2020

(median, 115; range, 94 to 152).

Of the 130 confirmed cases, 123 (95%)

were hospitalized, with a median

duration of hospitalization of 5

days (range, 1 to 43 days). Of those

hospitalized, 36 (29%) were admitted

to an intensive care unit, and 23 (19%)

required mechanical ventilation. Nine

(7%) cases died. Seventy-five (58%)

cases were male. Older adults were

more often affected, with 105 (81%)

cases occurring among individuals ≥50

years (overall median age, 64 years;

range, 29 to 90 years). Of the 129 cases

for which race and ethnicity were

reported, 114 (88%) were white (of

which 2 were Hispanic), 11 (9%) were

Black, two (2%) were Asian American,

one (<1%) was American Indian, and

one (<1%) was other race. Sixty-six

(51%) cases were diagnosed during

June through September. Seventy-nine

(61%) were residents of the Twin Cities

metropolitan area and 51 (39%) were

residents of Greater Minnesota. Three

(2%) confirmed cases were part of an

outbreak associated with a hotel spa

pool (the outbreak had 2 additional

confirmed cases who were non-

Minnesota residents).

Although most cases are diagnosed by

Legionella urinary antigen test, culture

is useful for public health purposes

because clinical and environmental

isolates can be compared by molecular

typing in outbreak investigations. MDH

requests that clinical laboratories

submit Legionella isolates, as well

as available lower respiratory tract

(sputum, BAL) specimens from

confirmed and suspect cases for

culture and molecular typing.

Listeriosis

Twelve culture-confirmed listeriosis

cases were reported in 2021.

All were hospitalized, and three

died. The median age of cases

was 68 years (range, 44 to 93

years). Ten (83%) cases had Listeria

monocytogenes isolated from blood

and two from cerebrospinal fluid

(CSF). There were no pregnancy-

associated cases among culture-

confirmed cases in 2021. Nine cases

were white, two were Asian, and

three were Black; none were of

Hispanic ethnicity. The 12 cases are

slightly greater than the median

number of cases reported from 1996

through 2020 (median, 8 cases;

range, 3 to 19). Three cases were

part of outbreaks in 2021; two cases

were part of a multi-state outbreak

associated with an unknown

commercially distributed vehicle, and

one 2021 case was part of a multi-

DCN 48;1 2022

continued...

state outbreak associated with leafy

greens that occurred from 2014 to

2022.

In 2019, national case definitions

were modified to include “probable”

and “suspected” cases of listeriosis.

In 2021, three probable or suspected

cases were identified. Two probable

cases were a maternal-neonate pair;

the neonate had a CSF specimen test

positive by a culture-independent

diagnostic test that was not

subsequently culture-confirmed at

the MDH PHL, and the mother was

not tested. One suspected case was

identified in an individual with L.

monocytogenes isolated from an

ankle swab at a clinical laboratory.

Lyme Disease

Lyme disease is caused by Borrelia

burgdorferi, a spirochete transmitted

to humans by bites from Ixodes

scapularis, the blacklegged tick.

Recently, a new species, B. mayonii,

has also been identified as a cause

of human disease, and 11 cases have

been reported in Minnesota residents

since 2013, 1 in 2021. Data for these

cases is included in the summary data

below. In Minnesota, the same tick

vector also transmits the agents of

babesiosis, anaplasmosis, one form of

ehrlichiosis, and a strain of Powassan

virus.

In 2021, 1,033 confirmed Lyme

disease cases (18 cases per 100,000

population) were reported. In

addition, 869 probable cases

(physician-diagnosed cases that did

not meet clinical evidence criteria

for a confirmed case but that had

laboratory evidence of infection)

were reported. Overall, the number

of reported cases of Lyme disease

has been increasing for many years,

despite yearly fluctuations. The

median number of cases from 2010

through 2019 (median, 1,190; range,

896 to 1,431) was higher compared

to the median from 2000 to 2009

(median, 915; range, 463 to 1,239)

(Figure 1). Data for 2020 are not

available due to surveillance changes

made during the COVID-19 pandemic.

Of the confirmed Lyme disease cases

reported, 642 (62%) cases were male,

and the median case age was 45 years

(range, 2 to 94). Physician-diagnosed

erythema migrans (EM) was present

in 697 (67%) cases. Three hundred

seventy-one (36%) cases had one or

more late manifestations of Lyme

(5), and Togo (5), as well as several

other countries in sub-Saharan Africa.

The case reporting Asian travel had

visited Thailand.

Meningococcal Disease

No meningococcal cases were reported

in 2021.

Mumps

No mumps cases were reported in

2021.

Neonatal Sepsis

Statewide surveillance for neonatal

sepsis includes reporting of any

bacteria (other than coagulase-

negative Staphylococcus) isolated

from a sterile site in an infant <7 days

of age, and mandatory submission of

isolates. In 2021, 43 cases (0.68 cases

per 1,000 live births) were reported

compared to 45 cases in 2020. There

were 5 deaths. All were identified

via blood. Most cases (81%) were

culture-positive within the first 2

days of life. Group B Streptococcus

was most common (13) followed by,

Escherichia coli (12), Streptococcus

viridans (6), Enterococcus spp.

(4), Haemophilus influenzae (2), and 1

each of Actinomyces, Brevivacterium

spp., Gordonia spp., Streptococcus

pneumoniae, and Staphylococcus

aureus.

Pertussis

In 2021, 29 pertussis cases (1 per

100,000 population) were reported.

Laboratory confirmation was available

for 26 (90%) cases, none (0%) of

which were confirmed by culture and

8 (28%) of which were confirmed by

PCR. In addition, 7 (24%) cases met

the clinical case definition and were

epidemiologically linked to laboratory

confirmed cases, and 3 (10%) met the

clinical case definition only. Twenty

(69%) cases occurred in residents of

the metropolitan area.

Paroxysmal coughing was the

most common reported symptom,

which 24 (83%) cases experienced.

Approximately 36% (10) reported

disease, including 241 with a history

of objective joint swelling, 108 with

cranial neuritis including Bell’s Palsy,

6 with lymphocytic meningitis, 16

with acute onset of 2nd or 3rd degree

atrioventricular conduction defects,

and 1 with radiculoneuropathy, and

confirmation by Western immunoblot

(positive IgM ≤30 days post-onset

or positive IgG). Of the 934 cases

with known onset dates, onset

of symptoms peaked from June

through August, with 68% of EM

cases experiencing symptom onset in

June or July. This timing corresponds

with peak activity of nymphal I.

scapularis ticks in mid-May through

mid-July. Most cases either resided

in or traveled to endemic counties

in north-central, east-central, or

southeast Minnesota, or Wisconsin.

Malaria

Malaria is a febrile illness caused

by several protozoan species in the

genus Plasmodium. The parasite is

transmitted to humans by bites from

infected Anopheles genus mosquitoes.

The risk of malaria is highest in the

tropical and sub-tropical regions of

the world. Although local transmission

of malaria frequently occurred in

Minnesota over 100 years ago, all

cases reported in Minnesota residents

in recent years have been imported

infections acquired abroad.

In 2021, 64 cases (1.1 per 100,000

population) were reported. Fifty-

six (88%) cases were identified

with P. falciparum, 2 (3%) with P.

vivax, 2 (3%) with P. ovale, 1 (2%)

with P. malariae and 1 (2%) with

mixed Plasmodium species infection.

In 2 cases (3%), the testing performed

was unable to identify a species. The

median age of cases was 40 years

(range, 3 to 81). Of the 53 cases with

known race, 48 (91%) were Black, 3

(5%) were white, 1 (2%) was Asian, and

1 (2%) identified as other race. Sixty-

three cases were Minnesota residents

at the time of their illness, 48 (75%)

of whom resided in the seven-county

metropolitan area. Of the 36 cases with

known country of birth, 4 (6%) were

born in the United States. Exposure

and travel information was not

available for 3 cases, while 60 (94%)

cases likely acquired malaria in Africa,

and 1 patient reported travel to Asia.

Sixteen countries were considered

possible exposure locations in Africa

for malaria infections, including Liberia

(17), Nigeria (8), Cameroon (6), Kenya

DCN 48;1 2022

whooping. Although commonly

referred to as “whooping cough,”

very young children, older individuals,

and persons previously immunized

may not have the typical “whoop”.

Post-tussive vomiting was reported

in 14 (49%) cases. Infants and young

children are at the highest risk for

severe disease and complications. In

2021, no cases were diagnosed with

Pneumonia, none were hospitalized,

and no deaths occurred.

Pertussis is increasingly recognized

in older children and adults. During

2021, cases ranged in age from 9

months to 74 years. No cases were

diagnosed in children <6 months of

age, 5 (19%) in children 6 months

through 4 years, none in children

5-12 years, two (8%) cases occurred

in adolescents 13-17 years, and

19 (73%) in adults ≥18 years. The

median age of cases was 38 years.

Infection in older children and

adults may result in exposure of

unprotected infants. During 2021,

one case was in an infant <1 year

of age. A likely source of exposure

wasn’t identified for that case. ACIP

recommends vaccination of women

at ≥20 weeks gestation during each

pregnancy to protect young infants.

Ensuring up-to-date vaccination of

children, adolescents, and adults,

especially those in contact with

young children, is also important.

Children aged 7 and under receive

the DTaP vaccine, while older

children and adults receive the Tdap

vaccine. Vaccinating adolescents

and adults with Tdap will decrease

the incidence of pertussis in the

community and thereby minimize

infant exposures.

Although unvaccinated children

are at highest risk for pertussis,

fully immunized children may also

develop disease, particularly as the

number of years since vaccination

increases. Disease in those

previously immunized is usually

mild. Efficacy for currently licensed

DTaP vaccines is estimated to be

71-84% in preventing typical disease

within the first 3 years of completing

the series. Waning immunity

sharply increases at 7 years of age,

and most are susceptible by 11-12

years of age when the Tdap booster

is recommended. Recent studies

suggest that immunity wanes

sharply 2 years from receipt of Tdap.

Of the 8 (28%) cases who were 7

months to 6 years of age, 5 (63%)

were known to have received at

least a primary series of 3 doses of

DTP/ DTaP vaccine prior to onset

of illness; 3 (38%) received fewer

than 3 doses and were considered

preventable cases.

Reporting rules require clinical

isolates of Bordetella pertussis

be submitted to the PHL to track

changes in circulating strains.

Isolates were not subtyped using

pulsed-field gel electrophoresis

(PFGE). Nationally, isolates have

had low minimum inhibitory

concentrations (falling within the

reference range for susceptibility)

to erythromycin and azithromycin.

Only 11 erythromycin-resistant B.

pertussis cases have been identified

in the United States.

Laboratory tests should be

performed on all suspected cases.

B. pertussis is rarely identified

late in the illness, therefore, a

negative culture does not rule out

disease. A positive PCR result is

considered confirmatory in patients

with a 2-week history of cough

illness. PCR can detect non-viable

organisms. Consequently, a positive

PCR result does not necessarily

indicate current infectiousness.

Patients with a 3-week or longer

history of cough illness, regardless

of PCR result, may not benefit

from antibiotic therapy. Whenever

possible, culture should be done

in conjunction with PCR testing.

Serological tests may be useful for

those with coughs >2 weeks.

Pertussis remains endemic despite

an effective vaccine and high

coverage rates with the primary

series. Reported incidence of

pertussis has consistently increased

over the past 10 years, particularly

in middle school-aged children,

adolescents, and adults.

Q Fever

Q fever is an acute to chronic illness

caused by Coxiella burnetii. Cattle,

sheep, and goats are the primary

sources of infection. Transmission

can occur through contact with

infected animals or animal tissue,

inhalation of aerosolized bacteria,

ingestion of unpasteurized dairy

products, and tick bites.

In 2021, six confirmed cases of Q

fever were reported, including one

chronic case and five acute cases.

The confirmed chronic case was

a 71-year-old male whose illness

included splenomegaly, vasculitis, and

endocarditis. He was likely exposed

through drinking raw milk in the past.

The median age of the acute cases

was 36 years (range, 9 to 67 years); all

were male. Four (80%) identified as

white, one (20%) identified as Black,

and all identified as non-Hispanic.

All were likely exposed through

contact with animals, including goats,

camels, and sheep. One (20%) case

was likely acquired internationally.

Three (60%) cases were hospitalized

for a median of 3 days (range, 3 to

17 days). Three (60%) acute cases

developed hepatitis as a result of

their infection, one (20%) developed

hepatosplenomegaly, and one (20%)

developed myocarditis.

From 1997 to 2021, 32 confirmed

acute cases and 11 chronic cases of

Q fever were reported. The median

age of acute cases was 60 years

(range, 11 to 77 years); the median

age of chronic cases was also 60

years (range, 5 to 78 years). Twenty-

four (86%) of the 28 cases for which

both race and ethnicity were known

identified as White, non-Hispanic;

3 (11%) identified as Black, non-

Hispanic; and 1 (4%) identified as

mixed race, non-Hispanic. During

this time, 26 (79%) of the 33 cases

for whom exposure information

was available were likely exposed

through direct or indirect contact with

animals; 4 (12%) were likely exposed

through ingestion of unpasteurized

dairy products; and, 3 (9%) were

likely exposed through a tick bite. Ten

(36%) of the 28 cases with known

occupations were employed in an

agriculture-related occupation at the

time of their exposure.

Rabies

In Minnesota, the animal reservoirs

for rabies are skunks, which carry the

North-central U.S. skunk rabies virus

variant and multiple bat species, each

with their own host-adapted rabies

virus variant. Dogs, cats, and livestock

are generally exposed to rabies

through encounters with skunks.

Vaccinating these domestic animals

for rabies provides a buffer between

wildlife and people.

In 2021, 42 (2.2%) of 1,932 animals

tested were positive for rabies. This

is similar to those identified in 2020

(40, [1.9%] of 2,114 animals tested)

and similar to the number of positives

identified annually in the previous

DCN 48;1 2022

continued...

Murray

Pine

Aitkin

Cass

Hubbard

Wilkin

Itasca

St. Louis

Cook

Wash-

ing-

ton

Lake

Sueur

Rice

Goodhue

NoblesRock Jackson Martin Faribault Freeborn Mower Fillmore Houston

Winona

Olmsted

DodgeSteeleWasecaBlue EarthWatonwanCottonwood

Pipestone

Nicollet

Wabasha

Dakota

Scott

Isanti

Brown

Sibley

Carver

WrightMeeker

Kandiyohi

Renville

Redwood

Sherburne

LyonLincoln

Yellow Medicine

Lac Qui Parle

Swift

Big Stone

PopeStevens

Traverse

Chippewa

Stearns

Benton

Carlton

Kanabec

Mille

Lacs

Crow Wing

Morrison

Wadena

Todd

DouglasGrant

Otter Tail

Becker

Clay

Clear

Water

Mahnomen

Norman

Red Lake

Pennington

Polk

Beltrami

Marshall

Koochiching

Lake

of the

Woods

RoseauKittson

McLeod

Ramsey

Anoka

Hennepin

Chisago

* Placement of symbol in county does not represent exact geographical location of the case.

Species No.

Skunk 3

Cat

Bat

decade. In 2021, 90% (38/42) of rabid

animals were bats followed by skunks

(3/42 [7%]). There was one rabid

domestic animal, a cat (Figure 5).

Cases of human rabies in the

United States are rare, with 1 to 6

cases reported annually. In 2021,

Minnesota reported its first human

rabies case since 2007. This case

was bitten by a rabid bat, received

timely and appropriate rabies post-

exposure prophylaxis (PEP), yet

developed rabies 6 months after the

bite. This was the first documented

failure of rabies PEP in the western

hemisphere and the first to involve

bat variant rabies virus. An extensive

investigation was conducted and

determined that this case had a

previously unrecognized, impaired

immune system, which likely

prevented an appropriate immune

Figure 5. Rabid Animals by County, 2021*

response against the rabies virus.

Ensuring adequate immune response

to rabies vaccines is increasingly

important given the rising prevalence

of immunocompromised adults in the

United States. This investigation does

not challenge the high efficacy or

safety profile of rabies PEP biologics.

From 2003 to 2021, 983 (2.3%) of

43,621 animals tested in Minnesota

were positive for rabies. The median

number of rabies-positive animals

identified annually was 48 (range 28

to 94). From 2003 to 2021, 337/761

(44.3%) skunks, 57/966 (5.9%) cattle,

490/12,978 (3.8%) bats, 9/375

(2.4%) horses, 49/12,729 (0.4%) cats,

29/12,419 (0.2%) dogs, 1/1,323 (0.1%)

raccoons, and 12/2,137 (0.6%) other

animals (fox [6], goat [3], woodchuck,

bison, deer) tested were positive

for rabies. In contrast to the eastern

United States, where raccoons carry

a raccoon host-adapted variant of

the virus and are the most common

source of terrestrial rabies, rabies in

raccoons is rare in Minnesota.

Respiratory Syncytial Virus

(RSV)

Laboratory-confirmed respiratory

syncytial virus disease (RSV) became

reportable for all hospitalized residents

of the metropolitan area in September

2016. Any death occurring statewide

within 60 days of a positive RSV test

is also reportable. Typically, RSV

circulates during the colder months of

the year (October-April), however RSV

activity has differed in recent years

from the usual seasonality.

From October 1, 2021 – April 30, 2022,

623 cases were reported. From May

1, 2022 – September 30, 2022, 365

cases were reported. Combined, from

October 1, 2021 – September 30, 2022,

there were 988 cases reported (32

cases per 100,000 persons), compared

to 670 cases were reported (22 cases

per 100,000 persons) from October

2020 – September 2021. The overall

median age was 11 months (range: 0

days – 98 years). Sixty-eight percent

(674) were <2 years of age: 35% (347)

were <6 months, 17% (163) were 6

months – 11 months, and 17% (164)

were 1 year – <2 years. Fourteen

percent (137) were 2-4 years, 4% (36)

were 5 – 17 years, 3% (30) were 18 –

49 years, 3% (27) were 50 – 64 years,

and 9% (84) were >65 years of age.

Overall, 51% of RSV cases were male

and 50% were white.

Thirty-nine percent (393) of cases

had a co-morbid condition at the

time of their illness and presence

of a co-morbid condition increased

significantly as age increased. The most

common co-morbid conditions for

cases <2 years of age were prematurity

(58%), chronic lung disease (19%)

and cardiovascular disease (15%). For

cases 2 – 17 years of age, the most

common co-morbid conditions were

chronic lung disease (55%), neurologic

conditions (42%), cardiovascular

disease (24%), and feeding tube

dependent (18%). The most common

underlying conditions for adults

18-64 years of age and older adults

(≥65 years) were chronic metabolic

disease (38% and 52% respectively),

cardiovascular disease (48% and

66% respectively), chronic lung

disease (56% and 49% respectively),

DCN 48;1 2022

multi-state outbreak associated with

a specific producer of raw, frozen,

breaded, stuffed chicken products that

included 36 cases in 11 states. This

was the 10th outbreak associated with

this type of product in Minnesota, and

the 5th with products from the same

producer since 1998.

Three culture-confirmed cases of S.

Javiana infection were part of a multi-

state outbreak of 4 cases from 2 states

associated with pre-packaged Napa

salad. The Napa cabbage component

was the most plausible contaminated

ingredient. However, the source or

mechanism of contamination could

not be determined.

Two culture-confirmed cases of S.

Muenster infection were part of a

multi-state outbreak associated with

contact with bearded dragons. The

genetic relatedness of isolates from

this outbreak to S. Muenster isolates

from a previous 2020 outbreak

associated with bearded dragons

indicates a continuing source of

contamination in the pet bearded

dragon industry.

One culture-confirmed case of S.

Vitkin infection was part of a multi-

state outbreak of 12 cases from 10

states associated with contact with

bearded dragons.

Two culture-confirmed cases of S.

Uganda infection were part of a multi-

state outbreak of 56 cases from 26

states associated with contact with

bearded dragons.

Seven culture-confirmed cases and

one probable case of S. Enteritidis

infection were linked to a Mexican-

style restaurant where the potential

vehicle was chicken or guacamole

salad. Improper cold holding and lack

of adequate cleaning/sanitization may

have contributed to the outbreak.

One culture-confirmed case of S.

Typhimurium infection and one

culture-confirmed case of S. Infantis

infection were part of a multi-state

outbreak that included 40 cases (26

S. Typhimurium and 14 S. Infantis)

from 17 states. The outbreak vehicle

was antipasto trays containing various

Italian-style meats.

Twenty-four laboratory-confirmed (22

culture-confirmed and 2 CIDT-positive

only) cases and four probable cases of

S. Enteritidis infection were associated

with watermelon consumption at an

Asian-style buffet restaurant. The

and hypertension (46% and 81%

respectively).

Thirteen RSV-associated deaths were

reported during the regular the 2021-

2022 respiratory season. Eleven deaths

occurred during hospitalization and 3

within 60 days of hospital discharge.

From May 1, 2021 – September 30,

2021, 3 deaths were reported: 2 during

hospitalization and 1 within 60 days of

hospital discharge. The median age of

all deaths was 78 years (range 69 years

to 96 years), and all 17 deaths had

co-morbid conditions. Identification

of additional RSV-associated deaths is

ongoing.

Salmonellosis

During 2021, 1,024 Salmonella

cases were reported. Of those, 853

were culture-confirmed Salmonella

and 171 only tested positive by a

culture-independent diagnostic test

(CIDT) and not subsequently culture-

confirmed.The 853 culture-confirmed

cases of Salmonella infection (15.1

per 100,000 population) reported

in 2021 represents a 6% increase

from the median number of culture-

confirmed cases reported annually

from 2011 to 2020 (median, 808

cases; range, 660 to 1,009) (Figure 2).

Of the 91 serotypes identified

among culture-confirmed cases

in 2021, 6 serotypes, S. Enteritidis

(191), S. Typhimurium (108), S. I

4,[5],12:i:- (90), S. Infantis (63), S.

Newport (51), and S. Oranienburg

(40) accounted for 64% of cases.

Salmonella was isolated from stool

in 741 (87%), urine in 58 (7%),

and blood in 48 (6%) cases. Other

specimen sources included body fluid,

groin, left knee, perineal swab, skin/

subcutaneous tissue, and vaginal

swab.

The incidence of Salmonella infections

was 16.2 per 100,000 population

among cases who reported Black

race, 14.3 among cases who reported

Asian race, 12.5 among cases who

reported white race, and 11.2 among

cases who reported American Indian/

Alaska Native race. The incidence of

Salmonella infections was 20.8 per

100,000 population for cases who

reported Hispanic ethnicity.

One hundred eighty-four (22%)

culture-confirmed cases were

hospitalized; the median length of

hospital stay was 4 days (range, 1 to

70 days). Two culture-confirmed

cases died. An 80 year-old died of

bacteremia, Salmonella infection,

and respiratory distress 7 days after

S. Newport was isolated from blood.

A 76 year-old died of respiratory

failure, air embolism, septic

shock, and Salmonella infection

9 days after S. Paratyphi B var.

L(+) tartrate+ (formerly Java) was

isolated from stool.

Of the 730 culture-confirmed cases

with known travel history, 94 (13%)

had traveled internationally during

the week prior to their illness onset.

There were three S. Typhi cases;

one travelled to Sierra Leone, one

traveled to Mexico, and one had no

known international travel. There

was one S. Paratyphi A case with no

known international travel.

During 2021, 171 cases with

specimens that were positive

by a CIDT conducted at a

clinical laboratory, but were not

subsequently culture-confirmed,

were reported. CIDTs have

become widely adopted by clinical

laboratories for the detection of

Salmonella in stool. The median

age of the CIDT-positive only cases

was 52 years (range, 0 to 92 years).

Fifty (29%) cases were hospitalized;

the median hospital stay was 6 days

(range, 2 to 66 days). Two cases

died.

One hundred sixty-eight laboratory-

confirmed (166 culture-confirmed

and 2 CIDT-positive only) cases were

part of 20 Salmonella outbreaks in

2021. Sixteen of the 20 outbreaks

involved foodborne transmission,

and 4 were due to animal contact.

Twelve of the outbreaks involved

cases with exposure in multiple

states. The 20 outbreaks resulted

in a median of 3 culture-confirmed

cases per outbreak (range, 1 to 56).

In addition, there was one multi-

state investigation that included

two Minnesota cases, which CDC

classified as an outbreak with an

unknown source.

Five culture-confirmed cases and

two probable (clinically defined

illness) cases of S. I 4,5,12:i:-

infection were associated with

a funeral event that served food

prepared in private homes. The

source of contamination and vehicle

of transmission were not identified.

Four culture-confirmed cases of S.

Enteritidis infection were part of a

DCN 48;1 2022

continued...

Disease

2017 2018 2019 2020 2021

No. Rate No. Rate No. Rate No. Rate No. Rate

Chlamydia

23,528 444 23,564 444 24,535 463 21,942 413.7 22,578 425.7

Gonorrhea

6,519 123 7,542 142 8,063 152 10,217 192.6 9,671 182.3

Syphilis, Total

934 17.6 918 17.3 1127 21.2 1093 20.6 1457 27.5

Primary/

Secondary

292 5.5 292 5.5 385 7.3 461 7.8 564 10.6

Early NP/NS*

313 5.9 286 5.4 367 6.9 365 6.9 415 7.8

Unknown/Late

327 6.2 330 6.2 354 6.7 303 5.7 463 8.7

Congenital**

2 3 10 15.1 21 32.3 7 11.2 15 23.6

*NP=Non-primary; NS=Non-secondary

**Congenital syphilis rate per 100,000 live births.

Note: Data exclude cases diagnosed in federal or private correctional facilities.

most likely cause of the outbreak was

cross contamination from raw meat to

watermelon, partially due to the use

of a spray hose. This was the third S.

Enteritidis outbreak associated with

this restaurant since 2018.

Eight culture-confirmed cases and

nine probable cases of S. Typhimurium

infection were associated with a

graduation party. The vehicle of

transmission was not identified.

Two culture-confirmed cases of S.

Enteritidis infection were part of a

multi-state outbreak for which the

suspected vehicle was chicken. There

were 50 cases from 20 states.

Twenty-eight culture-confirmed

cases and 10 probable cases of S.

Oranienburg infection were part of a

multi-state outbreak associated with

whole, fresh onions imported from

Mexico that included 1,040 cases in

39 states. Following a 2020 multi-

state S. Newport outbreak, this was

the second consecutive year in which

there was a multi-state outbreak

of over 1,000 Salmonella infections

associated with onions.

Two culture-confirmed cases of S.

Thompson infection were part of a

multi-state outbreak associated with

seafood primarily from a distributor in

Colorado. There were 115 cases from

15 states, and one of the Minnesota

cases was part of a subcluster in

Colorado.

Table 3. Number of Cases and Incidence Rates (per 100,000 Persons)

of Chlamydia, Gonorrhea, and Syphilis

Three culture-confirmed cases of S.

I 4,5,12:i:- infection were part of a

multi-state outbreak associated with

Italian-style meat sticks that included

36 cases from 11 states. Timely and

detailed reinterviewing of cases

allowed MDH staff to rapidly identify

the outbreak vehicle with only three

cases.

Three culture-confirmed cases of S.

Typhimurium infection were linked

to a Minnesota restaurant where

the vehicle of transmission was not

identified. Poor hand-washing and

bare-hand contact practices at the

restaurant might have contributed to

the outbreak.

Ten culture-confirmed cases and one

probable case of S. Typhimurium

infection were linked to a Minnesota

Mexican-style restaurant. Lettuce was

a possible vehicle of transmission. An

infected food worker was the most

plausible source of contamination,

and therefore any ready-to-eat food

item could have been a vehicle of

transmission.

One culture-confirmed case and

four probable cases of S. Enteritidis

infection, plus a culture-confirmed

case in an out-of-state resident, were

linked to the same Asian-style buffet

restaurant that was the source of

another S. Enteritidis outbreak that

occurred earlier in 2021 (reported

above). No specific food vehicle was

identified, but extensive issues in

the restaurant created a high risk for

contamination of equipment, food

preparation surfaces, and ready-to-eat

food items.

Two culture-confirmed cases of

S. Newport infection were likely

associated with a college cafeteria;

however, a vehicle was not identified.

One culture-confirmed case of S.

Saintpaul infection was part of a

multi-state outbreak of 60 cases from

14 states that was likely associated

with tomatoes. One specific grower

in Florida was identified as a

common source of tomatoes for

three subcluster establishments by

traceback.

Fifty-six culture-confirmed cases

of Salmonella infection with

various serotypes (S. Infantis [37],

S. Enteritidis [9], S. Hadar [8], S.

Mbandaka [1], and S. Muenchen

[1]) were associated with a multi-

state outbreak linked to live poultry

contact. Nationally, there were 1,135

people infected with the outbreak

strains across 48 states, with illness

onset dates ranging from December

15, 2020 to October 10, 2021.

Sexually Transmitted Diseases

Gonorrhea and chlamydia are

monitored through a mostly passive

surveillance system involving review of

submitted case reports and laboratory

reports. Syphilis is monitored

DCN 48;1 2022

*Residence information missing for 247 cases of chlamydia and 75 cases of gonorrhea.

**Suburban is defined as the metropolitan area (Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, and

Washington Counties), excluding the cities of Minneapolis and St. Paul.

^Case counts include persons by race alone. Population counts used to calculate results include race alone or in

combination.

^^No comparable population data available to calculate rates.

^^^Persons of Hispanic ethnicity may be of any race.

Note: Data exclude cases diagnosed in federal or private correctional facilities.

through active surveillance, which

involves immediate follow-up

with the clinician upon receipt

of a positive laboratory report.

Although overall incidence rates

for sexually transmitted diseases

(STDs) in Minnesota are lower than

those in many other areas of the

United States, certain population

subgroups have very high STD rates.

Specifically, STDs disproportionately

affect adolescents, young adults, and

persons of color.

Chlamydia

Chlamydia trachomatis infection

is the most commonly reported

infectious disease in Minnesota.

In 2021, 22,578 chlamydia cases

(425 per 100,000 population) were

reported. This is a 3% increase

compared to 2020 (Table 3).

Adolescents and young adults are at

highest risk for acquiring a chlamydia

infection (Table 4). The chlamydia

rate is highest among 20 to 24-year-

olds (2,249 per 100,000), followed

by the 15 to 19-year-old age group

(1,494 per 100,000). The incidence

of chlamydia among adults 25 to 29

years of age (1,041 per 100,000) is

considerably lower but has increased

in recent years. The chlamydia rate

among females (541 per 100,000) is

nearly twice the rate among males

(308 per 100,000), most likely due

to more frequent screening among

females.

Chlamydia infection incidence is

highest in communities of color

(Table 4). The rate among black

non-Hispanics (2,024 per 100,000)

is 10.3 times higher than the rate

among white non-Hispanics (196

per 100,000). Although black,

non-Hispanic persons comprise

approximately 5% of Minnesota’s

population, they account for 25%

of reported chlamydia cases. Rates

among Asian/Pacific Islanders (382

per 100,000), Hispanic, any race (900

per 100,000), and American Indian/

Alaska Natives (970 per 100,000) are

4.6 to 4.9 times higher than the rate

among white, non-Hispanic persons.

Chlamydia infections occur

throughout the state, with the

highest reported rates in Minneapolis

(1,206 per 100,000) and St. Paul (894

per 100,000). All geographical areas

around our state saw an increase in

the rate of chlamydia between 2020

and 2021. Every county in Minnesota

had at least 2 cases in 2021.

Table 4. Number of Cases and Incidence Rates (per

100,000 Persons) of Chlamydia, Gonorrhea, and

Primary/Secondary Syphilis by Residence, Age,

Race/Ethnicity, and Gender, 2021

Disease

Chlamydia Gonorrhea

Primary/

Secondary

Syphilis

No. Rate No. Rate No. Rate

Total

22,578 426 9,606 181 564 10.6

Residence

Minneapolis

4,613 1206 2,923 764 190 49.7

St. Paul

2,548 894 1,466 514 81 28.4

Suburban**

7,585 348 2,755 126 147 6.7

Greater Minnesota

7,519 306 2,377 97 146 5.9

Age

<15 years

166 16 64 6 1 0.1

15-19 years

5,494 1494 1,328 361 18 4.9

20-24 years

7,997 2249 2,282 642 61 17.2

25-29 years

3,880 1041 1,982 532 105 28.2

30-34 years

2,293 669 1,595 465 113 33.0

35-39 years

1,267 386 1067 325 78 23.8

40-44 years

649 184 594 168 60 17.0

45-49 years

361 89 319 79 30 7.4

50-54 years

222 55 188 47 41 10.2

55+ years

249 19 252 19 57 4.3

Gender

Male

8109 308 5,306 202 420 16

Female

14452 541 4,351 163 143 5.4

Transgender/

unknown^^

17 14 1

Race^/Ethnicity

White, non-Hispanic

9,066 196 3,075 67 239 5.2

Black, non-Hispanic

5,687 2024 3,849 1370 144 51.3

American Indian/

Alaska Native

653 970 410 609 58 86.1

Asian/PI

844 382 216 98 15 6.8

Other^^

625 169 53

Unknown^^

3,450 1,328 15

Hispanic^^^

2,253 900 559 223 40 16.0

DCN 48;1 2022

continued...

Gonorrhea

Gonorrhea is the second most

commonly reported STD in

Minnesota. In 2021, 9,671 cases

(182 per 100,000 population) were

reported. This is a 5% decrease

compared to 2020 (Table 4).

Adolescents and young adults are

at greatest risk for gonorrhea (Table

4), with rates of 361 per 100,000

among 15 to 19- year-olds, 642

per 100,000 among 20 to 24-year

old, and 532 per 100,000 among

25 to 29-year-olds. Gonorrhea

rates for males (202 per 100,000)

were higher than females (163 per

100,000).

Communities of color are

disproportionately affected by

gonorrhea. The incidence of

gonorrhea among black, non-

Hispanics (1370 per 100,000) is

20.6 times higher than the rate

among white, non-Hispanics (67 per

100,000). Rates among Asian/Pacific

Islanders (98 per 100,000), Hispanic,

any race (249 per 100,000), and

American Indian/Alaska Natives

(609 per 100,000) are up to 9 times

higher than among white, non-

Hispanic persons.

Gonorrhea rates are highest in

the cities of Minneapolis and St.

Paul (Table 4). The incidence in

Minneapolis (764 per 100,000) is

over 1.5 times higher than the rate

in St. Paul (514 per 100,000), almost

6 times higher than the rate in the

suburban metropolitan area (126

per 100,000), and almost 8 times

higher than the rate in Greater

Minnesota (97 per 100,000).

Syphilis

Surveillance data for primary

and secondary syphilis are used

to monitor morbidity trends

because these represent recently

acquired infections. Data for early

syphilis (which includes primary,

secondary, and early non-primary/

non-secondary stages of disease)

are used in outbreak investigations

because these represent infections

acquired within the past 12 months

and signify opportunities for disease

prevention.

The incidence of primary/secondary

syphilis in Minnesota is lower than

that of chlamydia or gonorrhea

(Table 3), but has remained elevated

since an outbreak began in 2002

among men who have sex with men

(MSM). In 2021, there were 564

cases of primary/secondary syphilis

in Minnesota (10.6 cases per 100,000

persons), which is a 35% increase

compared to 2020.

In 2021, the number of early syphilis

cases increased by 25%, with 979

cases, compared to 783 cases in

2020. The incidence remains highly

concentrated among MSM. Of the

early syphilis cases in 2021, 723 (73%)

occurred among men; 444 (61%) of

these were MSM. Thirty-one percent of

the MSM diagnosed with early syphilis

were co-infected with HIV. The number

of women reported has continued to

increase over the past 10 years from 13

early syphilis cases in 2011 to the near

historic high of 253 cases reported in

2021.

14 congenital syphilis cases were

reported in 2021. Syphilis may be

passed from a pregnant person to the

unborn baby through the placenta. The

infection can cause miscarriages and

stillbirths. Infants born with congenital

syphilis can suffer a variety of serious

health problems, including deformities,

seizures, anemia, and jaundice. The

CDC reported this fall that the number

of infants born with syphilis has

increased more than 200% in the past

four years and last year reached a 20-

year high. In Minnesota, the number

and rate of congenital syphilis cases

among infants has increased from 2.9

in 2015 to 23.6 per 100,000 live births

in 2021.

Shigellosis

In 2021, 220 Shigella cases were

reported. Of those, 109 were

culture-confirmed (1.9 per 100,000

population). The remaining 111 were

only tested by a culture-independent

diagnostic test (CIDT) and not

subsequently confirmed. The 220

culture-confirmed Shigella cases

represents a 38% increase from the

79 cases reported in 2020, and is 22%

less than the median annual number

of cases reported from 2011 to 2020

(median, 140 per year; range, 79 to

556). S. flexneri accounted for 76

(70%) cases, S. sonnei for 28 (26%)

cases, S. boydii for 2 (2%) cases, and

S. dysenteriae for 1 (1%) case. The

species was not identified for 2 (2%)

cases. Culture-confirmed cases ranged

in age from 1 to 89 years (median, 32

years). Nine percent of cases were

≤5 years of age; 85% of cases were

18 years of age or older. Seventy-five

percent of cases were male. Twenty-

three (21%) cases were hospitalized.

No cases died.

In 2021, of the 220 reported cases, 217

patients were positive for Shigella by a

CIDT conducted in a clinical laboratory.

Of the 208 corresponding specimens

that were received at MDH, 104

(50%) were subsequently culture-

confirmed. The remaining 111 cases

only had specimens that were positive

by a CIDT conducted at a clinical

laboratory and were not subsequently

culture-confirmed. The median age

of the CIDT-positive only cases was 32

years (range, 1 to 89 years). Thirteen

(12%) CIDT-positive only cases were

hospitalized; the median hospital stay

was 2 days (range, 1 to 7 days). One

CIDT-positive only case died.

Thirty-eight percent of cases reported

either non-white race (30 of 100

cases) or Hispanic ethnicity (16 of

100 cases). Of the 93 cases for which

travel information was available, 21

(23%) travelled internationally (8 of 25

[32%] S. sonnei and 12 of 65 [18%] S.

flexneri). Eighty-four percent of cases

resided in the Twin Cities metropolitan

area, including 61% in Hennepin

County and 17% in Ramsey County.

There was one outbreak of shigellosis

associated with a restaurant.

In 2021, 35 of the 103 Shigella isolates

received at MDH were tested

for antimicrobial resistance. Of

the 35 isolates, 74% (26 isolates)

were resistant to ampicillin, 74%

(26 isolates) were resistant to

trimethoprim-sulfamethoxazole,

and 46% (16 isolates) had decreased

susceptibility to azithromycin (DSA). All

but one of the 16 of the DSA isolates

were collected from adult males; the

remaining isolate was collected from

an adult female with no history of

international travel. Among the 10

adult male cases with DSA infection

and available information, 7 (70%)

reported sexual contact with a male

during the week before illness onset.

Staphylococcus aureus

Invasive Staphylococcus aureus (SA)

infections are classified into one of

three categories: hospital-onset (HO-

SA); healthcare-associated, community-

onset (HACO-SA); and community-

associated (CA-SA). SA must be

isolated from a normally sterile body

site greater than three days after the

date of initial hospital admission for a

DCN 48;1 2022

case to be considered HO-SA. HACO-

SA cases have at least one healthcare-

associated (HA) risk factor identified

in the year prior to infection. Examples

of HA risk factors include residence

in a long-term care facility, recent

hospitalization(s), dialysis, presence of

an indwelling central venous catheter,

and surgery. CA-SA cases do not have

any identifiable HA risk factors present in

the year prior to infection.

In 2005, as part of the Emerging

Infections Program (EIP) Active Bacterial

Core surveillance (ABCs) population-

based surveillance of invasive methicillin-

resistant S. aureus (MRSA) was initiated

in Ramsey County. Surveillance was

expanded to include Hennepin County

in 2008. The incidence rate was 15.8

per 100,000 in 2021 compared to 14.8

per 100,000 population in 2020. In 2021,

MRSA was most frequently isolated from

blood (88%, 250/286), and 15% (43/286)

of the cases died in the hospital. HACO-

MRSA cases comprised the majority

(61%, 175/286) of invasive MRSA

infections in 2021, CA-MRSA cases

accounted for 27% (76/286) and 12%

(35/286) cases were HO-MRSA. The

median age for all cases was 50 years

(range, 3 to 98); the median age was 53

(range, 3 to 98), 52 (range, 9 to 89), and

43 (range, 3 to 93) for HO-, HACO-, and

CA-MRSA cases, respectively.

In August 2014, as part of the EIP Active

Bacterial Core surveillance (ABCs)

population-based surveillance of invasive

methicillin-sensitive S. aureus (MSSA)

was initiated in Hennepin and Ramsey

Counties. The incidence rate was 29.5

per 100,000 in 2021 compared to 30.6

per 100,000 population in 2020. In 2021,

MSSA was most frequently isolated from

blood (80%, 425/533), and 11% (60/533)

of the cases died in the hospital. HACO-

MSSA cases comprised the majority

(54%, 291/533) of invasive MSSA

infections in 2021, CA-MSSA cases

accounted for 35% (189/533) and 10%

(53/533) cases were HO-MSSA. The

median age for all cases was 58 years

(range, <1 to 97); the median age was 61

(range, 4 to 97), 54 (range, <1 to 78), and

53 (range, 2 to 97) for HO-, HACO-, and

CA- MSSA cases, respectively.

Vancomycin-intermediate S. aureus

(VISA) and vancomycin-resistant

S. aureus (VRSA) are reportable in

Minnesota, as detected and defined

according to Clinical and Laboratory

Standards Institute approved standards

and recommendations. These

recommendations stipulate a minimum

inhibitory concentration (MIC)=4-8 μg/

ml for VISA and MIC≥16 μg/ml for

VRSA. Patients at risk for VISA and

VRSA generally have underlying health

conditions, such as diabetes and end

stage renal disease requiring dialysis,

previous MRSA infections, recent

hospitalizations, and recent exposure

to vancomycin. There have been no

VRSA cases in Minnesota (MN). There

were no VISA cases reported in 2021.

Between 2008 and 2021, we had 19

VISA confirmed cases: 2008 (3), 2009

(3), 2010 (2), 2011 (5), 2013 (3), 2016

(2) and 2019 (1). Among all cases of

VISA in MN, 11 (58%) were male and the

median age was 64 years (range, 27 to

86). Of those cases with known history

(18), 89% reported recent exposure to

vancomycin.

Streptococcal Invasive Disease

– Group A

Invasive Group A Streptococcus disease

(GAS) is defined as GAS isolated from

a usually sterile site such as blood,

cerebrospinal fluid, or a wound

when accompanied with necrotizing

fasciitis or streptococcal toxic shock

syndrome (STSS). Two-hundred and

fourteen cases (3.8 cases per 100,000

population), including 19 deaths,

were reported in 2021, compared to

271 cases and 20 deaths in 2020. The

median age of cases was 55 years

(range, 6 months to 93 years). Fifty-

five percent of cases were residents

of the metropolitan area. Allowing for

multiple presentations per patient,

105 (49%) had cellulitis, 42 (20%)

bacteremia without another focus

of infection, 30 (14%) septic shock,

29 (13.5%) had septic arthritis and/

or osteomyelitis, 16 (7.5%) abscess

(not skin), 16 (7.5%) pneumonia, and

11 (5%) necrotizing fasciitis. Forty-

three (20%) cases were injection drug

users in 2021, including one death,

compared to 48 cases (18%) and 0

deaths in 2020. Twelve (5.6%) cases

were residents of long-term care

facilities. Ten facilities had a single

case, one facility had 2 cases.

Allowing for multiple infection types

per patient, the 19 deaths included 11

that were diagnosed with septic shock,

11 cellulitis, 2 bacteremia without

another focus of infection, 1 abscess

(not skin), 1 necrotizing fasciitis, 1

pneumonia, and 1 with STSS. Of the 19

deaths, the most frequently reported

underlying conditions were diabetes

(11), chronic kidney disease (7),

atherosclerotic cardiovascular disease

(6), current tobacco smoker (6),

heart failure (5), chronic obstructive

pulmonary disease (4), solid organ

malignancy (3), and obesity (3). Sixteen

fatal cases had two or more underlying

conditions, and 1 had none reported.

Streptococcal Invasive Disease

– Group B

Five-hundred-eighty-four cases of

invasive group B Streptococcus (GBS)

disease (10.3 per 100,000 population),

including 41 deaths, were reported in

2021. By age group, annual incidence

was highest among infants <1 year

of age (49.7 per 100,000 population)

and cases aged ≥70 years (30.1 per

100,000). Nineteen (46%) of the 41

deaths were among cases ≥65 years.

Fifty percent of cases were residents

of the metropolitan area. Bacteremia

without a focus of infection occurred

most frequently (27%), followed by

cellulitis (20%), septic arthritis (10%),

osteomyelitis (9%), septic shock

(9%), pneumonia (6%), abscess (5%),

and meningitis (1%). The majority

(85%) of cases had GBS isolated from

blood; other isolate sites included

joint fluid (9%), peritoneal fluid (3%),

cerebrospinal fluid (<1%), and bone

(<1%).

Thirty-four cases were infants and 4

were maternal cases, compared to

33 cases in 2020. Thirteen infants

developed early-onset disease

(occurred within 6 days of birth [0.2

cases per 1,000 live births]), and 17

infants developed late-onset disease

(occurred at 7 to 89 days [0.3 cases

per 1,000 live births]). One stillbirth/

spontaneous abortion was associated

with the 4 maternal GBS infections.

Since 2002, there has been a

recommendation for universal

prenatal screening of all pregnant

women at 35 to 37 weeks gestation.

In light of this, we reviewed the

maternal charts for all early-onset

cases reported in 2021. Overall, 7

of 13 women who delivered GBS-

positive infants underwent prenatal

screening for GBS. Of these, 2 were

positive and 5 were negative. One

of the 6 women who did not receive

prenatal screening was screened

upon admission to the hospital

prior to delivery and was positive.

Among the 13 women who delivered

GBS-positive infants, 7 received

intrapartum antimicrobial prophylaxis.

An update of GBS perinatal prevention

guidance was published by the

American College of Obstetricians and

DCN 48;1 2022

100

120

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

Cases per 100,000 Population

Year of Diagnosis

Unknown Serotype

Other Serotypes

Additional Serotypes in PCV-13

Serotypes in PCV-7

PCV-13 contains the 7 serotypes in PCV-7 (4,6B,9V,14,18C,19F, and 23F) plus 6 additional serotypes (1,3,5,6A,7F, and 19A).

Gynecologists, and by the American

Academy of Pediatrics in July 2019.

Streptococcus pneumoniae

Invasive Disease

In 2021, 309 (5.5 per 100,000) cases of

invasive pneumococcal disease (IPD)

were reported. By age group, annual

incidence rates per 100,000 were 7.2

cases among children aged ≤5 years,

1.3 cases among children and adults

aged 5-39 years, 7.9 cases among

adults 40-64 years, and 13.1 cases

among adults aged ≥65 years.

Pneumonia occurred most frequently

(48% of infections), followed by

bacteremia without another focus of

infection (16%), septic shock (11%),

and meningitis (6%). Forty-six (15%)

cases died. Health histories were

available for 45 deaths, of which 40

had an underlying health condition.

The conditions most frequently

reported were current tobacco

smoker (16), diabetes (14), solid organ

Figure 6. Invasive Pneumococcal Disease Incidence Among Children <5 Years of Age,

by Year and Serotype Group, Metropolitan Area

malignancy (10), emphysema/chronic

obstructive pulmonary disease (10),

current alcohol abuse (9), obesity

(9), atherosclerotic cardiovascular

disease/ coronary artery disease (7),

chronic kidney disease (6), and heart

failure (6).

In 1999, the year before the pediatric

pneumococcal conjugate vaccine

(Prevnar [PCV-7]) was licensed, the

rate of IPD among children <5 years

of age in the metropolitan area

was 111.7 cases/100,000. Over the

years 2000-2002 there was a major

downward trend in incidence in this

age group (Figure 6). Rates in each

of the subsequent 8 years were level

or somewhat higher. Based on the

distribution of serotypes among

isolates from these cases, this increase

was limited to disease caused by

non-vaccine serotypes (i.e., serotypes

other than the 7 included in PCV-7)

(Figure 6).

In March 2010, the U.S. Food and Drug

Administration approved a 13-valent

pediatric pneumococcal conjugate

vaccine (PCV-13 [Prevnar 13]) which

replaced PCV-7. This vaccine provides

protection against the same serotypes

in PCV-7, plus 6 additional serotypes

(serotypes 1, 3, 5, 6A, 7F, and 19A).

From 2007 to 2010, the majority of

IPD cases among children <5 years

of age was caused by the 6 new

serotypes included in PCV-13 (Figure

6). Since 2011, the majority of IPD

cases among children <5 years of age

has been caused by serotypes not

included in PCV-13. In 2021, 13% of

cases with isolates available for testing

were caused by 7 of the PCV-13-

included serotypes: 3 (13%), 19F (5%),

19A (2%), 4 (1%), 18C (<1%), and 6B

(<1%).

In August 2014, the Advisory

Committee on Immunization Practices

(ACIP) recommended that all adults

≥65 years receive 1 dose of PCV-

13 followed by 1 dose of 23-valent

pneumococcal polysaccharide vaccine

6 to 12 months later. Among adults

≥65 years, 11% of cases in 2021 had

PCV-13 serotypes.

DCN 48;1 2022

100

2017 2018 2019 2020 2021

Number of Cases

Sub- Saharan Africa

South/ Southeast Asia

East Asia/ Pacific

Latin America/ Caribbean

Other*

* “Other” includes: Eastern Europe, North Africa/Middle East, and Western Europe

Year of Diagnosis

Figure 7. Non U.S.-Born Tuberculosis Cases by Region of Birth and Year of Report

Toxoplasmosis

Toxoplasmosis is an illness caused by

the coccidian protozoan Toxoplasma

gondii. Cats are the primary reservoir

and definitive host for T. gondii. T.

gondii transmission in the United

States is primarily foodborne,

through handling or consumption

of undercooked pork, lamb, or

venison containing bradyzoites, the

microscopic tissue cyst form of the

parasite. People also can be infected

through direct contact with cat feces

or soil that contains Toxoplasma

oocysts, or though consumption

of food or water that has been

contaminated with oocysts.

In 2021, 7 cases were reported (6

confirmed and 1 probable). This was

similar to the annual median of 9

cases reported from 2013 to 2020

(range, 2 to 14 cases). Fourteen

confirmed cases were identified in

2019 but only 2 confirmed cases

were identified in 2020, likely

reflecting challenges in toxoplasmosis

surveillance resulting from the

COVID-19 response.

In 2021, two cases were diagnosed

with ocular toxoplasmosis, 3 cases

with generalized toxoplasmosis,

and 2 with cerebral toxoplasmosis.

All 7 cases were acquired; no

cases were congenital. There

were no pregnancies reported

among cases. Three cases had

immunocompromising conditions.

The median age of cases was 43

years (range, 36 to 62 years). Five

cases (71%) were male. Two cases

were Asian/Pacific Islander, 1 case

was Black/African American, 1 case

was white, and 3 were of unknown

race; four cases were non-Hispanic, 2

were Hispanic, and 1 was of unknown

ethnicity.

Tuberculosis

In 2021, 134 tuberculosis (TB) cases

(2.4 per 100,000 population) were

reported. This represents a 15%

increase in the number of cases

compared to 2020, when there were

117 newly reported cases. Despite

this rebound in the number of new

cases in 2021, it was still 9% below

the case count in 2019. This followed

a similar trend seen at the national

level, most likely reflecting

lingering effects of the COVID-19

pandemic. This could be due to a

combination of factors, including

delayed diagnosis or misdiagnosis

of TB from shifting resources in

public health and underutilization

of healthcare services, together

with a true decrease in TB

incidence from COVID-19

mitigation strategies during the

pandemic. The TB incidence rate

in Minnesota was the same as the

overall rate in the United States.

Fourteen cases (10%) from 2021

have died as of March 2023, 11

(8%) due to TB disease.

Twenty-six counties (30%)

reported at least one case in 2021.

The majority of TB cases (76%)

occurred in the metropolitan area,

primarily in Hennepin (24%) and

Ramsey Counties (30%). Thirty

cases (22%) were from the other

five metropolitan counties, and

the remaining 24% of cases were

reported from greater Minnesota.

Among metropolitan area counties,

the highest TB incidence rate in

2021 was reported in Ramsey

County (7.3 per 100,000), followed

DCN 48;1 2022

by Anoka County (3.6 per 100,000).

The combined TB incidence rate

for the 7-county metropolitan area

was 3.3 per 100,000, compared

to 1.3 per 100,000 for all greater

Minnesota counties.

The largest groups of new TB cases

were those 25-44 and 45-64 years

of age at time of diagnosis (28%

each), followed by cases 65 years of

age and older (20%). Eight patients

(6%) were <5 years of age when

they were diagnosed.

Most TB cases (79%) were

identified only after seeking

medical care for symptoms of

disease. Targeted public health

interventions identified a portion

of the remaining 21% of cases,

including contact investigations

surrounding potentially infectious

patients (9%) and screening of new

refugee arrivals (2%). An additional

6% were identified through

other targeted testing for TB,

including employment screening

and other medical examinations

for immigration purposes. The

remaining five cases (4%) were

diagnosed with active TB disease

incidentally while being evaluated

for another medical condition.

TB incidence is disproportionately

high among racial and ethnic

minorities in Minnesota, as well

as nationally. In 2021, 11 cases

occurred among non-Hispanic

whites, a case rate of 0.2 per

100,000. In comparison, among

non-Hispanic persons of other

races, 56 cases occurred among

blacks/African-born persons (12.8

cases per 100,000), 52 among

Asians or Pacific Islanders (16.5

cases per 100,000), and one case

among American Indian or Alaska

Native persons (1.5 cases per

100,000). Fourteen cases were

Hispanic/Latino persons of any

race (4.4 cases per 100,000). The

majority of Hispanic/Latino (79%),

Asian/Pacific Islander (79%), and

black/African-born cases (96%)

were non-U.S. born.

In 2021, the percentage of TB

cases in Minnesota occurring in

persons born outside the United

States was 81%, compared to 71%

of TB cases reported nationally.

The 108 non-U.S.–born TB cases

represented 33 different countries

of birth; the most common region

of birth among these cases was

Sub-Saharan Africa (50% of non-

U.S. born cases), followed by South/

Southeast Asia (31%), Latin America

(including the Caribbean) (10%),

East Asia/Pacific (8%), and Eastern

Europe (<1%). (Figure 7).

Compared to the percentage of

cases who have lived in areas of the

world where TB is more common,

individuals in other high-risk groups

comprised smaller proportions

of the cases. Note that patients

may fall under more than one risk

category. Fifty percent occurred

in persons with certain medical

conditions (not including HIV/

AIDS), which increase the risk for

progression from latent TB infection

to active TB disease (e.g., diabetes,

COVID-19 infection, active smoking,

prolonged corticosteroid or other

immunosuppressive therapy, end

stage renal disease). One percent

of cases were co-infected with HIV.

Substance use (including excess

alcohol use and/or injection and

non-injection drug use) during

the 12 months prior to their TB

diagnosis was reported by 3% of

cases, and one percent reported

experiencing homelessness during

the 12 months prior to diagnosis.

By site of disease, 65% of cases

had pulmonary disease exclusively.

Another 9% had both pulmonary

and extrapulmonary sites of disease,

and 26% had extrapulmonary

disease exclusively. Among the 47

patients with an extrapulmonary

site of disease, the most common

sites were lymphatic (45%),

followed by peritoneal (19%)

and musculoskeletal (19%).

Extrapulmonary disease is generally

more common among persons

born outside the United States, as

seen in cases reported nationally

as well as in Minnesota. Thirty-

eight percent of non-U.S.–born

cases in Minnesota had at least one

extrapulmonary site of disease,

compared to only 23% of U.S.-born

cases.

Of 94 culture-confirmed TB cases

with drug susceptibility results

available, 10 (11%) were resistant

to at least one first-line anti-TB

drug (i.e., isoniazid [INH], rifampin,

pyrazinamide, or ethambutol),

including 9 cases (10%) resistant

to at least INH. There were 4 new

cases of multidrug-resistant TB

(MDR-TB, or resistance to at least

INH and rifampin) reported in 2021,

making up 4% of culture-confirmed

cases.

Tularemia

Tularemia is an acute illness

caused by Francisella

tularensis subspecies tularensis (type

A) or holarctica (type B). Routes of

transmission include arthropod bites

(particularly ticks and deer flies),

contact with infected animals, and

exposure to contaminated water

or soil. There are six main clinical

forms of disease and all include

fever: ulceroglandular, glandular,

pneumonic, oropharyngeal,

oculoglandular, and typhoidal.

In 2021, one probable glandular

tularemia case was reported. The case

was a 13-year-old female who was

likely exposed through a tick bite.

From 2007 to 2021, 24 tularemia

cases were reported in Minnesota,

with a range of 0 to 6 cases annually.

Twelve cases had ulceroglandular,

7 had glandular, 2 had pneumonic,

and 3 had typhoidal tularemia. Ten

of 15 cases with a known tularemia

subtype had type B, and 5 had type

A. The median age of cases was 40

years (range, 2 to 87 years). Thirteen

cases were likely exposed through a

tick or biting fly bite, 2 through water

exposure, 3 through a cat scratch or

bite, and 2 by inhaling the bacteria;

likely exposures for 3 cases could not

be determined. Sixteen of 20 cases for

whom race was known were White,

1 was Black, 2 were American Indian/

Alaska Native, and 1 was Asian/Pacific

Islander.

Unexplained Critical Illnesses

and Deaths of Possible

Infectious Etiology and Medical

Examiner Deaths Surveillance

MDH conducts surveillance for

unexplained deaths and critical

illnesses in an effort to identify those

that may have an infectious etiology.

This surveillance is performed through

two complementary surveillance

systems, Unexplained Critical Illnesses

and Deaths of Possible Infectious

Etiology (known as UNEX), and Medical

Examiner (ME) Infectious Deaths

Surveillance (known as MED-X), which

is not limited to deaths with infectious

hallmarks. Focus is given to cases

<50 years of age with no significant

underlying conditions; however, any

case should be reported regardless of

the patient’s age or underlying medical

DCN 48;1 2022

conditions to determine if further

testing conducted or facilitated

by MDH may be indicated. Testing

of pre-mortem and post-mortem

specimens is conducted by the MDH

Public Health Lab (PHL) and the

CDC Infectious Diseases Pathology

Branch (IDPB).

In 2021, 206 cases met UNEX criteria

(191 deaths,15 critical illnesses),

compared to 131 cases in 2020. Of

the 206, 193 (94%) were reported

by providers and 13 deaths were

found by death certificate review.

One hundred twenty-five (60.5%)

cases presented with respiratory

symptoms; 55 (27%) with sudden

unexpected death; 14 (7%) with

neurologic symptoms; 4 (2%)

with shock/sepsis; 5 (2%) with

gastrointestinal symptoms; 2 (1%)

with cardiac symptoms; 1 (0.5%)

with multiple symptoms. The age

of cases ranged from 8 days to 89

years, with a median age of 47

years. Fifty-one percent resided in

the 7-county metropolitan area,

64% were male, and 16% were

non-MN residents who were either

hospitalized in MN or investigated

by a MN medical examiner.

There were 554 MED-X cases in

2021; 191 of these also met UNEX

criteria. The median age of the

cases was 48.5 years, and 62% were

male. There were 262 (47%) cases

found through death certificate

review and MEs reported 292 (53%)

cases. The most common syndrome

was pneumonia/upper respiratory

infection (n=319 [58%]).

There were 582 potential UNEX or

MED-X cases that had specimens

tested at the PHL and/or the IDPB.

Two hundred and sixty-one cases

were determined to be non-

infectious. One hundred forty-five

cases had pathogens identified as

confirmed, probable, or possible

cause of illness, including 139

UNEX deaths (Table 5). Among 49

unexplained deaths occurring in

those <50 years of age without any

immunocompromising conditions,

UNEX helped to identify the

pathogen(s) involved in 28 (57%)

cases. MED-X surveillance detected

an additional 129 cases with

pathogens identified by MEs as

the cause of death (Table 5). Cases

with pathogens of public health

importance detected included an

84-year-old male who developed

neurologic symptoms 5 months

after being bitten by a rabid bat

Table 5. UNEX/MED-X Pathogens Identified as

Confirmed, Probable, or Possible Cause of Illness, 2021*

Pathogen Identified

UNEX

(n=145)

MED-X

(n=129)**

Aspergillus spp.

0 1

Blastomyces dermatitidis

1 0

Candida albicans

0 1

Clostridioides difficile

0 1

Enterococcus spp.

0 1

Enterococcus faecalis

0 3

Escherichia coli

2 6

Fusobacterium spp.

1 1

Group A Streptococcus/Streptococcus pyogenes

2 2

Group B Streptococcus

1 3

Haemophilus spp.

1 0

Haemophilus haemolyticus

1 0

Haemophilus influenzae

2 1

Histoplasma capsulatum

0 1

Influenza A virus (no hemagglutinin typing information available)

1 1

Influenza A – H3

2 0

Klebsiella oxytoca

0 1

Klebsiella pneumoniae

2 0

Legionella pneumophila

4 0

Metapneumovirus

1 0

Mycobacterium spp.

0 1

Pneumocystis jirovecii

0 1

Powassan virus

1 0

Pseudomonas aeruginosa

0 1

Rabies virus

1 0

Respiratory Syncytial virus

0 2

Rhinovirus

1 0

Rhinovirus/Enterovirus

1 0

SARS-CoV-2 virus

105 86

Staphylococcus spp.

2 0

Staphylococcus aureus

2 6

Staphylococcus aureus - MRSA

4 4

Staphylococcus epidermiditis

0 1

Streptococcus spp.

7 0

Streptococcus anginosus

1 0

Streptococcus pneumoniae

10 8

Ureaplasma spp.

1 0

* Some cases had multiple pathogens identified as possible coinfections contributing to illness/death.

** MED-X includes pathogens identified by the Medical Examiner. If the cause was found through testing at

MDH/CDC it is included in the UNEX column.

DCN 48;1 2022

and received appropriate rabies

post exposure prophylaxis (PEP). An

autopsy revealed meningoencephalitis

consistent with rabies virus and

postmortem samples submitted to IDPB

and the CDC Rabies Branch confirmed

the presence of rabies virus. This case

represented the first documented

rabies PEP failure since the introduction

of modern cell-culture vaccines and

was contributed to the patient having

previously unrecognized impaired

immunocompromising condition.

The UNEX program also identified102

deaths due to SARS-CoV-2 virus

that occurred outside of traditional

healthcare facilities such as hospitals or

congregate care settings.

Due to the COVID-19 pandemic,

the UNEX/MED-X team expanded

surveillance testing to include swab

autopsies that were performed on

suspect infectious deaths that did not

have an autopsy performed. Nasal

pharyngeal swabs were collected

from decedents at funeral homes,

decedents’ homes and at long-term

care facilities. A total of 52 specimens

were submitted to MDH. 43 decedents

had known symptoms prior to death.

Of those, 25 (58%) had potential

pathogens detected, including SARS-

CoV-2 (n=24) and influenza A (n=1).

Varicella and Zoster

In 2021, 169 varicella cases were

reported (3.0 per 100,000 population).

Ninety-seven cases (57%) were from

the metropolitan area. Case ages

ranged from 95 days to 69 years.

Thirty-two cases (19%) were < 1 year,

73 (43%) were 1-6 years, 36 (21%) were

7-12 years, 10 (6%) were 13-17 years,

and 18 (11%) were ≥ 18 years of age.

Four cases were hospitalized; 1 was <

1 year, one was 1-6 years, and 2 were

>18 years. Two of the hospitalized

cases had not been vaccinated; one

had medical contraindications and

one was underage for vaccination. The

vaccination status of the other two

hospitalized cases was not available.

Varicella cases are often identified by

parents/guardians reporting to schools

and childcare facilities, rather than

directly reported by a clinician. In 2021,

108 cases (64%) had visited a health

care provider, 21 (12%) had consulted

a provider or clinic by telephone, 16

(10%) had been identified by a school

health professional, and 24 (14%) had

not consulted a health care provider.

Of the 168 cases for which information

regarding laboratory testing was

available, 64 (38%) had appropriate

testing performed.

One outbreak, defined as ≥5 cases

in the same setting, was reported in

2021. This occurred in an infant room

at a daycare center and included 5

cases, 4 of which were unvaccinated

due to being underage (first dose

recommended at age 12-15 months).

Zoster cases in children <18 years of

age are reportable in Minnesota; 34

cases were reported in 2021. Cases

may be reported by school health

personnel, childcare staff, or healthcare

providers. Ages ranged from 10 months

to 16 years (median 11 years). Varicella

vaccine became a requirement for

entry into kindergarten and 7th grade

in 2004, and the incidence of zoster

in children has declined from 15.7 per

100,000 population in 2006 to 2.6 per

100,000 population in 2021.

Zoster with dissemination or

complications (other than post-

herpetic neuralgia) in persons of

any age is also reportable; 56 such

cases were reported, and 44 (79%)

were hospitalized. Cases ranged

from 2 to 94 years of age, with a

median age of 60. Thirty-seven (66%)

had co-morbidities or were being

treated with immunosuppressive

drugs. Fourteen had disseminated

rash or disease, 17 had meningitis,

11 had cellulitis or other bacterial

superinfection, 8 had encephalitis, 3

had meningoencephalitis and 7 had

Ramsay-Hunt Syndrome. Cases with

disseminated rash or disease tended

to be older than cases with meningitis

without dissemination (median age of

63 vs. 43 years) and were more likely to

have immunocompromising conditions

or immunosuppressive drug treatment

(64% vs. 27%). Five deaths occurred;

two had encephalitis, two had

meningoenchephalitis, and one had

meningitis and Ramsay Hunt Syndrome.

All deaths were in cases > 65 years.

Only 19% of cases ≥50 years of age had

a record of receiving zoster vaccine.

Vibriosis

There were 91 Vibrio spp. (several

species) cases reported in 2021. Of

those, 24 were culture-confirmed and

67 were positive by culture-independent

diagnostic tests (CIDT) and not

subsequently culture-confirmed.

The 24 culture-confirmed cases of

Vibrio spp. infection reported in 2021

represent a 71% increase from the

14 cases reported in 2020, and a 20%

increase from the median annual

number of cases reported from 2010 to

2020 (median, 20 cases; range, 9 to 40).

V. parahaemolyticus accounted for 12

(50%) cases, V. alginolyticus, V. cholerae,

and V. fluvialis for 3 (13%) each, and V.

vulnificus for 1 (4%). Two isolates were

not received by the MDH Public Health

Laboratory for confirmation and species

identification. Serotyping was performed

on all three V. cholerae specimens, and

all were non-O1/non-O139.

Vibrio was isolated from stool in 16

(67%) cases, wounds in 3 (13%) cases,

blood in 2 (8%) cases, ear effusion in

2 (8%) cases, and urine in 1 (4%) case.

Three (13%) cases were hospitalized

for a median of 3 days (range, 1 to 4

days), and one case died.Travel history

was available for 21 cases. Fourteen

(67%) cases traveled out of Minnesota

in the week before their symptom

onset, including five (24%) who traveled

internationally. Two cases traveled

to Mexico, and one case each to the

Bahamas, Egypt, and Somalia. Of the

16 cases with Vibrio isolated from

stool who were able to be interviewed

about exposure to seafood in the week

before illness onset, 10 (63%) reported

consuming oysters. Of the remaining

six cases, three had other raw or

undercooked seafood.

In 2021, 74 patients were positive by

CIDTs conducted at a clinical laboratory.

Of these 67 (91%) were not culture-

confirmed and thus were classified as

probable cases. Eight (12%) specimens

were not received by the public health

laboratory for culture confirmation.

Fifty-nine (79%) were received at MDH

and tested negative by culture. Fifteen

(22%) probable cases were hospitalized

and two (3%) died.

Ten (19%) of the 53 probable cases

who were interviewed traveled

outside Minnesota, and five (9%)

traveled internationally (one each

to Cameroon, France, Mexico, New

Zealand, and Somalia). Among the 43

probable cases interviewed about food

exposures, three (7%) reported eating

raw oysters, and three (7%) reported

eating another type of raw seafood in

the week prior to illness onset. Thus,

probable cases differed markedly from

culture-confirmed cases regarding

exposures, suggesting a high proportion

of CIDT-positive tests represented false

positives.

There were no outbreaks of Vibrio spp.

infections identified in 2021.

Brooke Cunningham, Commissioner of Health

Division of Infectious Disease Epidemiology, Prevention and Control (IDEPC)

Beth Gyllstrom, PhD, MPH ............................................................................................................ Editor

Ruth Lyneld, M.D. ................................................................................................ State Epidemiologist

Elly Pretzel ........................................................................................................................... Producon

The Disease Control Newsletter is available on the MDH IDCN web site:

(http://www.health.state.mn.us/divs/idepc/newsletters/dcn/index.html)

Viral Hepatitis A

In 2021, 12 cases of hepatitis A

(0.2 per 100,000 population) were

reported. Ten cases were residents of

the metropolitan area. Six cases were

male. The median age was 33.5 years

(range 3 to 85). Race was known for all

cases; 9 (75%) were white, one (8.3%)

was Asian, and two (16.7%) were

reported as other race. Three (25%)

cases were known to be of Hispanic

ethnicity.

Ongoing outbreaks of hepatitis A

have been occurring in states across

the country since 2016, with at least

37 states reporting outbreaks. An

outbreak was declared in Minnesota in

August 2019 and 1 case was identified

as a part of the outbreak in 2021.

This case did not report risk factors,

but traveled to states with ongoing

outbreaks. The end of the Minnesota

outbreak was declared in September

2021. There were a total of 128 cases

identified over the course of the

outbreak. Of these cases, 89 (70%)

were hospitalized and there was one

death.

Of the 11 cases not associated with the

outbreak, 6 cases were associated with

international travel and two cases are

presumed to be a result of foodborne

exposure. No risk factor was identified

for the three remaining cases.

Viral Hepatitis B

In 2021, 10 cases of acute hepatitis

B virus (HBV) infection (0.2 per

100,000 population) were reported.

In 2012, the case definition for acute

hepatitis B was revised to include

laboratory confirmed asymptomatic

acute cases. Five of the 10 cases were

asymptomatic, laboratory-confirmed

infections.

The median age was 43 years (range

21 to 72). Six cases were residents of

the metropolitan area. Six cases were

male. Race was known for 9 cases:

four (44%) were White, one (11%)

was Asian, two (22%) were Black, one

(11%) was reported as multi-racial, and

one (11%) was reported as other race.

One (10%) case was known to be of

Hispanic ethnicity.

MDH received 190 reports of newly

identified chronic hepatitis B infections

in 2021. A total of 27,464 persons

are estimated to be alive and living in

Minnesota with chronic HBV infection.

The median age of chronic HBV cases

in Minnesota is 48 years.

In 2021, no perinatal hepatitis B

infections were identified in infants

born to hepatitis B-positive mothers.

Three hundred and six infants born

to hepatitis B-positive women during

2020 had post-serologic testing

demonstrating no infection.

Viral Hepatitis C

In 2021, 66 cases of acute hepatitis C

virus (HCV) infection (1.2 per 100,000)

were reported. In 2012, the case

definition for acute hepatitis C changed

to include documented asymptomatic

seroconversion. Of the 66 cases, 25

(38%) were asymptomatic, laboratory-

confirmed acute infection.

Fifty (76%) were residents of the

metropolitan area. The median age was

32 years (range, 18 to 66). Thirty-nine

(59%) cases were male. Race was known

for 61 cases: 29 (48%) were White, 18

(30%) were American Indian/Alaskan

Native, 7 (11%) were Black, one (2%)

was Asian, three (5%) were reported

as multi-racial, and three (5%) were

reported as other race. Six (10%) cases

were known to be of Hispanic ethnicity.

MDH received 1,049 reports of newly

identified chronic hepatitis C infections

in 2021. In 2016, the case definition for

chronic hepatitis C changed to exclude

those reported as having resolved their

infection. A total of 32,810 persons

are estimated to be alive and living in

Minnesota with chronic HCV infection.

The median age of these cases is 60

years.

In 2018, perinatal hepatitis C was added

as a nationally notifiable condition. In

2021, one case of perinatal hepatitis C

was reported. This case was known to

be White, non-Hispanic.