Outbreaks in Wisconsin

Outbreaks and Investigations

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

COVID-19 (Coronavirus Disease 2019)

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 safer when you are at home.
  • You should continue to limit your trips to the essentials.
  • The best way to interact with your friends, family, and neighbors is virtually.
  • Practice physical distancing. Standing at least 6 feet apart is a good rule.
  • When physical distancing is difficult, we recommend wearing a cloth face covering if you feel safe doing so.
  • Wash your hands frequently, and avoid touching your face.
  • Enjoy the beautiful weather by getting outside, but make sure to do it safely. For more tips on summer safety, check out our Questions for Summer.
  • If you have symptoms or have been exposed to COVID-19, get tested.

You are not alone. We are in this together. Do not hesitate to ask for help if you're feeling overwhelmed.

Latest news from Gov. Evers:

Media briefings, scheduled as needed:

Multistate Outbreak of Salmonella Infections Linked to Contact with Backyard Poultry
Updated 6/26/2020

The Wisconsin Department of Health Services (DHS) and local health departments are working with the Centers for Disease Control and Prevention (CDC) to investigate multiple outbreaks of Salmonella infections linked to contact with backyard poultry.

  • As of June 23, 2020, 465 people infected with one of the outbreak strains of Salmonella have been reported from 42 states. More than one-third (86 people) have been hospitalized and one death in Oklahoma has been reported.
  • Children younger than 5 years of age account for about one-third of the illnesses.
  • In Wisconsin, three laboratory-confirmed cases of Salmonella have been linked to this outbreak.

Outbreaks of Salmonella infections linked to contact with backyard poultry happen every year in the U.S. However, almost twice as many Salmonella infections linked to backyard poultry contact have been reported this year when compared to this time last year.

More information about the 2020 outbreak and previous years’ live poultry-associated outbreaks can be found on the CDC website.

More information about backyard poultry can be found on the DHS Backyard Poultry webpage.

Multistate Outbreak of Salmonella Infections Linked to Red Onions
Updated 8/3/2020

The Wisconsin Department of Health Services (DHS) and local health departments are working with the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of Salmonella Newport infections linked to the consumption of red onions.

  • As of July 31, 2020, CDC reports that 396 people in 34 states have been infected with the outbreak strain of Salmonella Newport. There have been 59 people hospitalized and no deaths.
  • Wisconsin has 5 laboratory-confirmed cases linked to this outbreak. One has been hospitalized.

DHS, CDC, and FDA are advising people not to eat, sell, or serve any onions from Thomson International, Inc., or food made with these onions. Onion types include red, white, yellow, and sweet varieties.

  • Check your refrigerator and kitchen for any of these onions or fresh foods made with them.
  • Check the package or look for a sticker on an onion to see if it is from Thomson International, Inc. If it is, do not eat it and throw it away.
  • If you can’t tell where your onions are from, do not eat them and throw them away.
  • If you made any foods with onions and you don’t know where they are from, do not eat them. Throw them away, even if no one has gotten sick.
  • Wash and sanitize any surfaces that may have come in contact with onions or their packaging, such as countertops, refrigerator drawers, knives, and cutting boards.

Epidemiologic and trackback information shows that red onions are a likely source of this outbreak.

  • Thomson International, Inc., of Bakersfield, CA, has been identified as a likely source of potentially contaminated red onions.
  • Due to the risk of cross-contamination, Thomson International, Inc. announced it will be recalling all varieties of onions that could have come in contact with potentially contaminated red onions. Further recall information will be provided as soon as it is made available.

This investigation is ongoing and Wisconsin DHS will provide updates when they are available.

See our salmonellosis page for information about common symptoms and treatment of Salmonella infection. If you have any symptoms of salmonellosis, see your doctor.

Additional information can be found on the following websites:

Multistate Outbreak of Cyclospora Infections Linked to Bagged Salad Mix
Updated 7/9/2020

The Wisconsin Department of Health Services (DHS), the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), and local health departments continue to work with the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of cyclosporiasis infections linked to the consumption of bagged salad mix containing iceberg lettuce, carrots, and red cabbage produced by Fresh Express.

As of July 24, 2020, a total of 641 people with laboratory-confirmed Cyclospora infections associated with this outbreak have been reported from 11 states. 37 people have been hospitalized and no deaths have been reported.

Wisconsin has 36 confirmed cases linked to this outbreak. None have been hospitalized.

Epidemiologic and trackback evidence indicates that bagged salad mix containing iceberg lettuce, carrots, and red cabbage produced by Fresh Express is a likely source of this outbreak.

  • The Public Health Agency of Canada is investigating an outbreak of Cyclospora infections occurring in 3 Canadian provinces. Exposure to certain Fresh Express salad products containing iceberg, red cabbage, and carrots is the likely source of their outbreak.
  • On June 27, 2020, Fresh Express recalled products containing either iceberg lettuce, red cabbage, or carrots and displaying the product code Z178 or a lower number.
  • On June 25, 2020, Fresh Express recalled 12- and 24-ounce bagged Walmart Marketside Classic Iceberg Salad, sold in Walmart stores.
  • On June 22, 2020, ALDI recalled 12-ounce bagged Little Salad Bar Garden Salad produced by Fresh Express.
  • On June 20, 2020, Hy-Vee issued a recall for Hy-Vee brand 12-ounce bagged Garden Salad produced by Fresh Express.
  • Evidence shows that Jewel-Osco brand Signature Farms Brand Garden Salad may be another source of this outbreak, but this product was not distributed to stores in Wisconsin. Jewel-Osco, in cooperation with Fresh Express, has recalled this product due to the association with illnesses in other Midwestern states.

DHS, the CDC, and FDA are advising people not to eat, sell, or serve any products that have been recalled for potential Cyclospora contamination.

The recalled products have use-by dates through July 14, 2020 and may still be in people’s homes. A full list can be found here.

  • Check your home for any of these salad products. Throw any remaining salad away, even if some of it has been eaten and no one has gotten sick.
  • If you live in Wisconsin and don’t know whether the bagged garden salad blend you have in your home is one of these salad products, don’t eat it and throw it away.

This investigation is ongoing and additional retailers and products may be impacted by this outbreak. Wisconsin DHS will continue to provide updates as information becomes available.

See our cyclosporiasis fact sheet for more information on common symptoms and treatment of cyclosporiasis. If you have any symptoms of cyclosporiasis, please contact your doctor.

Additional information can be found on the following websites:

Severe Lung Disease Among People who Reported Vaping
Updated 3/5/2020

Wisconsin Case Counts
As of March 5, 2020
We plan to update case counts by 2 p.m. on Thursdays.

More Information about the lung disease and vaping investigation can be found on the Lung Disease and Vaping Investigation webpage.

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

Case Status Number of Cases
Confirmed and Probable Cases* 108
Additional Patients Under Investigation 2

*We report confirmed and probable patient cases as one number because the two definitions are very similar, and this is the most accurate way to understand the number of people affected.

Campus Outbreaks of Adenovirus
Updated 12/4/2019

  • The Wisconsin Department of Health Services (DHS) is working with local health departments, the Centers for Disease Control and Prevention (CDC), and college and university health services directors in our state to track multiple outbreaks of respiratory illness caused by adenoviruses and to provide prevention information to students and staff.
  • People usually get sick with adenoviruses when they spend time with large groups of people (for example, at universities, hospitals, or schools). There are over 50 different types of adenoviruses. Usually adenoviruses cause mild illness, but sometimes they can be serious. The types of symptoms you have depend on which type of adenovirus you have and the part of the body that the virus is affecting.
    • Adenoviruses most commonly cause respiratory illness, which can range from cold and flu-like symptoms to bronchitis and pneumonia.
    • Some adenoviruses can cause diarrhea or pink eye, and in rare cases, inflammation of the bladder or severe neurological disease.
    • Anyone can get sick from an adenovirus. People with a weakened immune system, or those who have lung or heart problems are more likely to become very sick from an adenovirus.
    • Antibiotics do not work against adenoviruses.
  • There are a number of ways you can get an adenovirus:
  1. Breathing in adenovirus from the air: someone with the virus coughs or sneezes and the virus gets into the air. It is then breathed in by someone around them.
  2. Having direct contact with someone who has an adenovirus: touching or shaking hands with someone who has the virus on their skin and then touching your hands to your mouth, nose, or eyes.
  3. Touching surfaces with adenovirus: touching a surface (for example, a door knob, counter top, or phone) with adenovirus on it and then touching your hands to mouth, nose, or eyes. NOTE: Adenoviruses are able to survive on surfaces for a long time. It is important to wash toys, towels, and other surfaces often to make sure it doesn't spread to others.
  4. Having contact with poop: Some adenoviruses can spread through poop, for example, during diaper changing.
  5. Having contact with water that has adenovirus: Adenoviruses can also spread through water, such as swimming pools, but this is less common.

NOTE: Sometimes the virus can be shed (released from the body) for a long time after you recover from an adenovirus, especially if you have a weakened immune system. Usually you do not have any symptoms during this time of “virus shedding,” even though you can still spread adenovirus to others.

Outbreak of E. coli Infections Linked to Romaine Lettuce
Updated 12/19/2019

  • The Wisconsin Department of Health Services (DHS) is working with local health departments, the Wisconsin Department of Agriculture, Trade, and consumer Protection (DATCP), the Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of E. coli O157:H7 infections linked to romaine lettuce.
    • As of December 19, 2019, the CDC reports that 138 people in 25 states are infected with the outbreak strain of STEC. There have been 72 people hospitalized and 13 cases of hemolytic uremic syndrome (HUS), a type of kidney failure. No deaths have been reported.
    • As of December 19, 2019, Wisconsin has 33 confirmed cases linked to this outbreak. Of these, 14 people have been hospitalized and 2 have developed HUS.
  • Epidemiologic, laboratory, and traceback evidence collected so far shows that romaine lettuce from the Salinas, California, growing region is a likely source of this outbreak.
    • On November 21, 2019, a list of salad products were recalled after laboratory testing found the same strain of E. coli that was making people sick in Maryland in romaine lettuce harvested from the Salinas, California growing region.
    • On December 6, 2019, Wisconsin health officials found E. coli O157 in an unopened bag of chopped Fresh Express® brand Leafy Green Romaine salad from Salinas, California that was collected from an ill person’s home. On December 13, 2019, specialized laboratory testing called whole genome sequencing showed that the E. coli O157 strain found in the romaine matches the outbreak strain of E. coli that has made people in Wisconsin and other states sick.
    • While E. coli O157 was found in a bag of chopped Fresh Express® brand romaine, not all ill people in Wisconsin included in this outbreak report eating Fresh Express® brand romaine. No single brand, product, or type of romaine lettuce has been reported by all ill individuals. The investigation is ongoing to determine the source of contamination and if additional products are linked to illness.
  • Wisconsin DHS, the CDC, and FDA are advising people not to eat, sell, or serve any romaine lettuce harvested from Salinas, California, until more information is available.
  • While certain romaine-containing products were recalled, many romaine lettuce and romaine-containing products are still available on store shelves.
  • Advice to Consumers, Retailers, and Restaurants:
    • Most romaine lettuce products are labeled with a harvest location showing where they were grown. This advice includes all types of romaine lettuce harvested from Salinas, California, such as whole heads of romaine, hearts of romaine, and packages of precut lettuce and salad mixes which contain romaine, including baby romaine, spring mix, and Caesar salad.
    • Restaurants and retailers should check the label on bags or boxes of romaine lettuce, or ask their suppliers about the source of their romaine lettuce.
    • Suppliers, distributors, and others in the supply chain should not ship or sell romaine harvested in Salinas, California.
  • If you have romaine lettuce at home:
    • If the packaging has “Salinas” on the label in any form (whether alone or with the name of another location), don’t eat it, and throw it away.
    • If it isn’t labeled with a growing region, don’t eat it, and throw it away.
    • If you don’t know if the lettuce is romaine or whether a salad mix contains romaine, don’t eat it, and throw it away.
    • Wash and sanitize drawers or shelves in refrigerators where romaine lettuce was stored. Follow these five steps to clean your refrigerator.
  • If you are buying romaine lettuce at a store:
    • If the packaging has “Salinas” on the label in any form (whether alone or with the name of another location), don’t buy it.
    • If it isn’t labeled with a growing region, don’t buy it.
    • If the packaging has “Salinas” on the label in any form (whether alone or with the name of another location), don’t sell or serve it.
    • If it isn’t labeled with a growing region, don’t sell or serve it.
  • About Shiga toxin-producing E. coli (STEC):
    • People with STEC usually get sick with bloody diarrhea and stomach cramps 3-4 days after eating food contaminated with the germ. Contact your doctor if you think you ate romaine lettuce from the Salinas region of California and are having any symptoms.
    • Remember to wash your fresh fruits and vegetables before eating them, even if they have been “pre-washed.”
  • Additional information can be found on the following websites:

Hepatitis A Infection in a Mondovi Hansen's IGA Food Worker
Updated 11/21/2019

  • The Wisconsin Department of Health Services (DHS) is working with the Buffalo County Health Department, the Department of Agriculture, Trade, and Consumer Protection (DATCP), and the Centers for Disease Control and Prevention (CDC) regarding a confirmed case of hepatitis A virus infection in a food handler.
    • A food handler with hepatitis A infection is concerning because of the potential for food contamination.
    • This individual worked at the Mondovi Hansen’s IGA store deli while they were able to spread Hepatitis A, from October 28 through November 17, 2019.
    • Health officials are advising people who shopped at the Mondovi Hansen’s IGA during October 28 and November 17, 2019 and ate produce or deli items to call their doctor. They should ask about their risk of exposure to hepatitis A virus and options for vaccination (if not already vaccinated).
    • There is no risk of exposure outside of these dates.
  • Symptoms of hepatitis A infection can include abdominal pain, nausea, vomiting, diarrhea, dark urine, clay-colored stool, fever, chills, and yellow skin and eyes (jaundice).
    • Hepatitis A symptoms occur between 15 and 50 days after exposure and can last for several weeks to months. Most people recover from hepatitis A on their own, but occasionally patients may need to be hospitalized. Hepatitis A is rarely fatal.
    • Antibiotics do not work against hepatitis A virus.
  • The best ways to prevent the spread of hepatitis A virus are:
    • Get the hepatitis A vaccine. A single shot of the hepatitis A vaccine can help prevent an infection if given within two weeks of being exposed to hepatitis A virus.
    • Always wash your hands with soap and water after using the bathroom or changing a diaper. Hand sanitizer is NOT effective against Hepatitis A virus.
    • Thoroughly wash your hands with soap and water before and during food preparation and before eating food.
  • Additional information can be found at the following websites:

Hepatitis A Cases Linked to Blackberries
Updated 12/11/2019

  • The Wisconsin Department of Health Services (DHS) is working with local health departments, Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of hepatitis A that may be linked to fresh, non-organic blackberries. These blackberries were sold at Fresh Thyme Farmers Market and Woodman's Market stores during September 9 through September 30, 2019.
  • A single, common supplier of these berries has not been identified and no recall has been issued at this time.
    • Ill patients reported eating fresh, non-organic blackberries from Fresh Thyme Farmers Market or Woodman's Market stores in Indiana, Michigan, Minnesota, Missouri, Nebraska, and Wisconsin.
    • As of December 11, 2019, the CDC reports that 18 people in six states are infected with the outbreak strains of hepatitis A.
    • Wisconsin has five confirmed cases linked to this outbreak. Three cases in Wisconsin have been hospitalized.
    • Ill patients reported their illnesses starting between October 15 and November 5, 2019.
  • If you purchased any blackberries from a Fresh Thyme or Woodman's location between September 9 and September 30, 2019, do not eat them and throw them away.
    • Check your freezer for these blackberries. If you froze them to eat later, do not eat them and throw them away.
    • If you ate any of these blackberries within the last two weeks and are not vaccinated against hepatitis A, contact your doctor or local health department to discuss vaccination options.
  • Symptoms of hepatitis A infection can include abdominal pain, nausea, vomiting, diarrhea, dark urine, clay-colored stool, fever, chills, and yellow skin and eyes (jaundice).
    • Hepatitis A symptoms occur between 15 and 50 days after exposure and can last for several weeks to months. Most people recover from hepatitis A on their own, but occasionally patients may need to be hospitalized. Hepatitis A is rarely fatal.
    • Antibiotics do not work against hepatitis A virus.
  • Additional information can be found on the following websites:

Bovine Tuberculosis (TB) Investigation
Updated 11/2/18

  • The Wisconsin Department of Health Services (DHS) is working with the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) to investigate bovine tuberculosis (TB) in a dairy herd located in Dane County. The Wisconsin TB Program is working with Public Health Madison and Dane County to complete a contact investigation on the farm and identify individuals who may need TB testing.
  • Precautions are being taken by DATCP and the farm to ensure the safety of both meat and milk. Consumers and the general public are not at risk of contracting TB infection from this herd. Food safety laws prevent meat from infected animals from entering the food chain and the pasteurization process destroys disease-causing organisms in milk.
  • People are not at risk if they have made only brief visits to the affected farm, have not consumed raw milk, or have not worked closely for extended periods of time with animals. Visiting the farm, living near the farm, or making deliveries to the farm does not pose a risk for becoming infected with bovine TB.
  • Additional information on bovine TB can be found on the following websites:

 

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

Last Revised: August 3, 2020

 RESPONSE RESOURCES FOR WISCONSINITES — www.dhs.wisconsin.gov/covid-19/help.htm