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Outbreaks in Wisconsin

Below is a list of selected outbreaks, recalls, and investigations with wide impact in Wisconsin.

In recent weeks, the number of cases of cyclosporiasis cases being reported has increased across Wisconsin. Each summer, the United States typically experiences an increase in cyclosporiasis associated with produce imported from other countries where the Cyclospora parasite is common. Outbreaks in recent years have been associated with fresh, raw produce such as leafy greens and salads, cilantro, basil, berries, and vegetable trays. People can also become infected when they travel to tropical or subtropical countries where the parasite is common and consume contaminated food or water.

At this time, it is unclear if the increase in cases among people who do not report recent international travel is being caused by one common widely distributed food item or multiple possible sources associated with seasonal increases. To date, no Wisconsin residents have been linked to past or active outbreaks in other states.

As of 7/28/2023, 46 confirmed cases of cyclosporiasis in Wisconsin residents have been reported since June 1, 2023. This total includes both people who traveled internationally and domestically acquired infections.

2023 Wisconsin Outbreak Investigations: None currently.

Recall Information: None currently.

Advice to consumers

The Department of Health Services (DHS) and CDC (Centers for Disease Control and Prevention) urge people to take the following steps:

  • Handle fruits and vegetables safely:
    • Wash your hands, utensils, and food preparation surfaces before and after handling and preparing raw produce.
    • Rinse all fruits and vegetables thoroughly under running water. use a clean produce brush to scrub firmer produce. Produce that is labeled "prewashed" does not need to be washed again. Cut away any damaged or bruised areas on produce before preparing and eating.
    • Refrigerate produce as soon as possible or within two hours.
    • Cook produce when appropriate.

See the Food and Drug Administration (FDA) and CDC webpages for more information and to stay up to date on other food-borne outbreaks and recalls:


FDA: Investigations of Foodborne Illness Outbreaks

Updated 8/3/2023

The Wisconsin Department of Health Services (DHS) is working with local, state, and federal partners to investigate multiple outbreaks of Salmonella infections linked to contact with backyard poultry.

  • As of July 20, 2023, the CDC (Centers for Disease Control and Prevention) reports that 690 people, in 47 states and Puerto Rico have been infected with one of the outbreak strains of Salmonella.
  • Illnesses linked to these outbreaks started on January 1, 2023.
  • To date, 141 hospitalizations have been reported nationally, and no deaths.
  • Children under 5 years of age account for 23% of the illnesses nationally.
  • In Wisconsin since March 2023, 30 people have been infected with one of the outbreak strains of Salmonella.
  • Among Wisconsinites with infections linked to the national outbreak:
    • Case patients reside in 25 counties across the state.
    • Four infections have resulted in hospitalization. No deaths have been reported.
    • Case patients range in age from under 1 year to 75 years, with an average age of 27 years.

Outbreaks in Salmonella linked to backyard poultry occur every year in the U.S., including in Wisconsin residents. Many of these infections are preventable.

  • Poultry, including healthy and clean backyard poultry, can have Salmonella germs in their poop and on their bodies (feathers, feet, and beaks). The germs can easily spread to their cages, coops, eggs, and equipment used to care for them. People can get sick from Salmonella if they touch the birds or anything in their environment and then touch their mouth or food before washing their hands.
  • Children younger than 5 years are more likely to get sick with Salmonella because their immune systems are still developing. They also are more likely to put their fingers or other items with germs into their mouths.

People who own or have contact with poultry can take these steps to reduce the risk of becoming ill with salmonellosis:

  • Always wash your hands after touching backyard poultry, their eggs, or anything within the areas in which they live or roam.

  • Don’t kiss or snuggle backyard poultry, and don’t eat or drink around them.
  • Supervise kids around flocks and don’t let children younger than 5 years touch chicks, ducklings, or other backyard poultry.
  • Handle eggs safely.
  • Call your healthcare provider right away if you have any of these severe symptoms:
    • Diarrhea and a fever higher than 102°F
    • Diarrhea for more than three days that is not improving
    • Bloody stools
    • Prolonged vomiting that prevents you from keeping liquids down
    • Signs of dehydration, such as:
      • Making very little urine
      • Dry mouth and throat
      • Dizziness when standing up

For more information about how to reduce your risk of getting sick:

See the CDC webpage for more information on this investigation, and to stay up to date on other food-borne outbreaks and recalls:

CDC: Salmonella Outbreaks Linked to Backyard Poultry

Since May 14, 2022, the CDC (Centers for Disease Control and Prevention) has been monitoring new clusters of mpox in non-endemic countries throughout Europe, North America, and Australia. On June 30, 2022, the Wisconsin Department of Health Services (DHS) identified the first case of confirmed orthopoxvirus, presumed to be mpox, associated with this outbreak in a Wisconsin resident. DHS is working with the CDC and other state and local partners to enact measures to prevent the spread of mpox.

For more information on this outbreak, visit our Mpox Data webpage.

The risk of widespread transmission of mpox to the public is relatively low. People most at risk for mpox include:

  • People who had close physical contact with a person who has mpox (such as household members or intimate partners).
  • People who had close physical contact with a person who had a rash that looks like mpox.
  • People who attended events or venues where mpox transmission has occurred.
  • Gay, bisexual, or other men who have sex with men who had multiple sexual partners in the past 14 days.

DHS and CDC urge all Wisconsinites to take the following steps:

  • Know the symptoms and risk factors of mpox.
  • Avoid skin-to-skin contact with individuals who are showing a rash or skin sores. Don’t touch the rash or scabs, and don’t kiss, hug, cuddle, have sex, or share items, such as eating utensils or bedding with someone with mpox.
  • In areas where mpox is spreading, participating in activities with close, personal, skin-to-skin contact may pose a higher risk of exposure.
  • If you were recently exposed to the virus, contact a doctor or nurse to talk about whether you need a vaccine to prevent disease. Monitor your health for fever, chills, swollen lymph nodes and new, unexplained rashes and contact a health care provider if one occurs. If you become ill, avoid contact with others until you receive health care.
  • If you are sick with mpox, isolate at home until the rash has fully resolved, the scabs have fallen off, and a fresh layer of skin has formed.


The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspective Service (APHIS) continues to detect highly pathogenic avian influenza (HPAI) A (H5N1) in U.S wild birds and commercial poultry farms (domestic birds). HPAI is a serious disease that is highly contagious and often fatal to domestic birds including chickens, ducks, and turkeys. It can be spread by contact with infected birds or the premise where the birds are housed, equipment used on the premise with infected birds, and clothing worn by people working with poultry. HPAI can spread from birds to people and cause serious illness and even death. People who have gotten sick with HPAI have been in direct contact with infected birds or their premise.

As of September 15, 2022, 43 states have confirmed cases of HPAI in wild birds and 39 states have detected HPAI in poultry farms as a result of this outbreak. The most recent case in Wisconsin was detected on August 31, 2022, in a backyard flock in Washington County. This is the first case of HPAI detected in Wisconsin in domestic poultry since May 2022. Federal, state, and local agencies are working together to help stop the spread of HPAI by quarantining affected premises.

As of September 20, 2022, only one case of human infection with the current H5N1 virus has been detected in the United States. The case occurred in Colorado in a person who had direct exposure to poultry and was involved in the depopulation of poultry with presumptive H5N1 avian influenza. According to the Centers for Disease Control and Prevention (CDC), the current HPAI outbreak continues to pose a low risk to general community members. HPAI viruses also do not pose a food safety risk. Properly cooking poultry and eggs to the recommended internal temperature of 165˚F kills HPAI viruses.

Wild birds can become infected with HPAI and may show no signs of infection. When the wild birds migrate, they have the potential to spread HPAI to other birds and animals. On May 13, 2022, The Wisconsin Department of Natural Resources (DNR) confirmed that wild red fox kits in Wisconsin tested positive for a strain of HPAI. Additional cases have also been confirmed in other wild mammals including bobcats, skunks, bears, and seals. To prevent the spread of HPAI and other diseases to people and domestic animals, Wisconsinites and their pets should avoid touching sick or injured wild birds or mammals. It is important to avoid any wild animal that is behaving abnormally. Abnormal behavior includes:

  • Pacing or walking in circles,
  • Unbalanced posture, or
  • Head and body tremors.

If you or your pet had direct or close contact with a sick or wild animal, contact your local public health department or health care provider (or your pet’s veterinarian). Even with the detection HPAI in Wisconsin mammals, DHS and the CDC still consider the human risk assessment for the public as low.

About HPAI in people

HPAI viruses are a form of avian influenza that primarily affects birds. In rare circumstances, HPAI viruses can infect humans when prolonged close contact with infected birds occurs. No widespread person-person transmission of HPAI viruses has occurred, The sporadic HPAI cases that have occurred have ranged in severity from no symptoms to mild illness to severe disease that resulted in death.

Recommendations for the public

Viruses that spread from animals to people have the potential to mutate or combine with human influenza viruses to become more infectious variants. This is why public health measures to prevent the spread of HPAI to people are so important.

  • Everyone 6 months and older should get the flu vaccine every year to protect themselves against seasonal flu.
  • As a general precaution, people should avoid close contact with wild and domestic birds (poultry). People who have had contact with infected or sick birds should monitor for flu-like symptoms, seek medical care if they feel sick, and tell their health care provider that they had contact with infected birds.
  • Anyone involved in poultry production, even those with small backyard flocks, should evaluate their biosecurity measures to assure the health of their flock.
  • Whenever possible, people should avoid direct contact with wild birds and observe them only from a distance. People should also avoid touching any wild birds showing signs of HPAI and not touch dead birds or wildlife with their bare hands. If touching a dead bird is necessary, wear gloves or use a plastic bag to put it in the garbage. People should wash their hands with soap and water and throw away any gloves after disposing of dead birds or wildlife. Contact the DNR to report any sick or dead wildlife.

Additional resources

The CDC (Centers for Disease Control and Prevention) is working with state and local health departments to identify children with hepatitis (inflammation of the liver) of unknown cause. From November 2021 to February 2022, health care providers at a large children’s hospital in Alabama identified nine children experiencing significant liver injury, including three with acute liver failure. All nine children tested positive for adenovirus and those subtyped identified Adenovirus 41. All nine children were previously healthy and had no risk factors for hepatitis. The children were from different parts of the state and had no known contact with each other or common exposures prior to infection.

Since being notified of the cluster of cases in Alabama by the CDC, the Wisconsin Department of Health Services (DHS) is now investigating several past cases of hepatitis of unknown cause in Wisconsin children. Cases of hepatitis in children without known cause have also been detected in other parts of the United States and throughout the United Kingdom and Europe. According to a CDC update on May 6, 2022, at least 109 children in 25 states have been identified in the Unites States as part of the cluster of cases. Overall, at least 228 probable cases in 20 countries have been identified, according to the World Health Organization

As of May 12, 2022, the cause of this cluster of hepatitis cases is still unknown. However, it is important to note the virus that causes COVID-19 and the COVID-19 vaccines have been ruled out as possible causes. The median age of children with hepatitis of unknown cause in the U.S. is two years and children under five years are not yet eligible for COVID-19 vaccination. It is also unclear whether the number of children being diagnosed with hepatitis is increasing or if these cases can be attributed to improvements in hepatitis surveillance.

About Hepatitis

Hepatitis is inflammation of the liver that can be caused by viral infections, alcohol use, toxins, medications, and certain other medical conditions. The most common causes of viral hepatitis in the United States, the hepatitis A, hepatitis B, and hepatitis C viruses, have all been ruled out as a likely cause. Signs and symptoms of hepatitis include:

  • Fever
  • Fatigue
  • Loss of appetite
  • Nausea
  • Vomiting
  • Abdominal pain
  • Dark Urine
  • Light-colored stools
  • Join pain
  • Jaundice

About Adenovirus 41

Adenovirus type 41 is a common cause of diarrhea, vomiting, and fever in children. In some cases, it can also cause respiratory symptoms. There have been reports of hepatitis in children with weakened immune systems who have been infected with adenovirus type 41. However, adenovirus type 41 is not known to cause hepatitis in healthy children. While adenovirus type 41 has been detected in some children with unknown hepatitis, it has not been determined to be the cause of this cluster of cases at this time.


Contact your child’s health care provider if you have questions about your child’s health. DHS recommends parents with children who are concerned about hepatitis to:

  • Be aware of symptoms of liver inflammation
  • Keep children up to date on all recommended vaccinations
  • Take everyday steps to keep your child healthy:
    • Encourage hand washing
    • Avoid sick people
    • Cover coughs and sneezes, and
    • Avoid touching the eyes, nose, or mouth.


The Wisconsin Department of Health Services (DHS) and the Monroe County Health Department are working with federal partners at Fort McCoy to investigate an outbreak of measles among people who recently traveled from Afghanistan during the United States government’s emergency evacuation efforts. To date, all cases have been identified among people currently based at Fort McCoy. At the time of this update, there is no evidence of community spread in Wisconsin beyond Fort McCoy.

  • As of October 14, 2021, a total of 22 cases of measles has been confirmed.
  • People diagnosed with measles at Fort McCoy have ranged in age from 4 months to 26 years old and 14 (64%) have required treatment at area hospitals.
  • This information will be updated every Thursday at 2 p.m.

Most Wisconsinites are vaccinated against measles as children, which provides lifetime immunity. The risk of measles transmission in the surrounding communities is considered to be low at this time. However, people who have never been vaccinated and are exposed to a person with measles can spread the virus to others in the community, leading to outbreaks. The best way to prevent measles is to get vaccinated with the Measles, Mumps, Rubella (MMR) vaccine. Two doses of MMR vaccine are about 97% effective at preventing measles; one dose is about 93% effective. Wisconsin residents can check their vaccination status in the Wisconsin Immunization Registry (WIR).

Local health departments can provide MMR vaccine to uninsured adults through the Vaccines for Adults program, based on vaccine ability and capacity. The Wisconsin Vaccines for Children Program covers the cost of vaccines for eligible children.

In order to prevent further spread to Fort McCoy and surrounding communities, federal agencies coordinating the response offered vaccination against measles and other communicable disease to all Afghan evacuees in mid-September. Staff or visitors who have been to Fort McCoy and had contact with evacuees or the living areas of evacuees may be at increased risk for measles. DHS and the Monroe County Health Department are working closely with federal partners on base to offer vaccination to these higher risk groups in order to prevent spread.

Measles is a highly contagious, serious disease caused by a virus. The virus can be spread through the air and through direct contact with persons who are infected. Unvaccinated young children and other non-immune adults are at highest risk of serious disease from measles. Symptoms of measles generally start 10-12 days after exposure to the virus and include:

  • Runny nose
  • High fever (may be greater than 104 F)
  • Tiredness
  • Cough
  • Red, watery eyes, or conjunctivitis (“pink eye”)
  • A red rash with raised bumps that starts at the hairline and moves to the arms and legs three to five days after symptoms begin

For a full description of measles, see the DHS measles fact sheet and the CDC measles webpage.

In general, people born before 1957 are considered immune. All other adults without laboratory evidence of immunity should have at least one dose of measles-containing vaccine, and children should have two doses. See the DHS measles webpage for more information about measles and recommended vaccination schedules.

Wisconsin Investigation Details
We plan to update our data daily by 2 p.m.

We are closely monitoring COVID-19 with officials at local, state, and federal levels.

COVID-19 continues to be very contagious. We should continue to limit our interactions with others as much as possible to protect ourselves, our communities, and the capacity of our health care system.

You are not alone. We are in this together. Do not hesitate to ask for help.

Latest news from Gov. Evers

Media briefings, scheduled as needed

Wisconsin Case Counts
As of January 11, 2021

More information about the e-cigarette or vaping associated lung injury can be found on the Vaping and Lung Injury Investigation webpage.

Media requests should go to the DHS media or 608-266-1683.

Case Status Number of Cases
Confirmed and Probable Cases* 119

*Reporting the number of confirmed and probable cases of EVALI in Wisconsin during July 2019-current date.

To view previous outbreaks and investigations, please visit our Past Outbreaks in Wisconsin page.

Related pages
Last revised August 4, 2023