Past Outbreaks in Wisconsin

Archived Outbreaks and Investigations

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

For current outbreaks and investigations, please visit our Outbreaks in Wisconsin page.

Stack of folders full of paper documents

2019 Outbreaks

Outbreak of E. coli O157 Infections Linked to Fresh Express Sunflower Crisp Salad Kits
Final Update 1/15/2020

Fresh Express Sunflower Crisp chipped lettuce kit

Salmonellosis Associated with Consuming Beef Tartare at Restore Public House in La Crosse
Final Update 9/6/2019

Fresh, paper-thin sliced raw beef

  • The Wisconsin Department of Health Services (DHS), in collaboration with the La Crosse County Health Department, investigated an outbreak of salmonellosis associated with consuming beef tartare served at Restore Public House in La Crosse between July 10 and July 12, 2019.
  • 35 restaurant patrons were interviewed during the investigation. Seven confirmed and 10 probable (ill but not tested) cases were linked to this outbreak.
  • Restore Public House voluntarily removed the beef tartare dish from their menu once they were notified of the illnesses.
  • See the DHS salmonellosis fact sheet for more information on common symptoms of salmonellosis. If you have any symptoms of salmonellosis, please contact your doctor.
  • Consumption of raw or undercooked meat, poultry, or eggs can increase your risk of foodborne illness. See the DHS food safety webpage for more information on safe food practices.
  • Additional information can be found on the following websites:

Multistate Outbreak of Multidrug-Resistant Salmonella Infections Linked to Contact with Pig Ear Dog Treats
Final Update 10/30/2019

Dried pig ears.

  • The Wisconsin Department of Health Services (DHS) and local health departments worked with the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) to investigate a multistate outbreak of salmonellosis linked to contact with pig ear dog treats.
    • 154 people in 34 states were infected with the outbreak strains of Salmonella.
    • 35 people were hospitalized, with no deaths reported. Children younger than 5 years accounted for 19% of illnesses.
    • In Wisconsin, 4 laboratory-confirmed cases were linked to this outbreak.
  • CDC and FDA have dropped their warning to avoid buying or feeding any pig ear treats, except for treats that have been recalled. Consumers should not give recalled pig ears to their pets. Consumers should always wash their hands right after feeding any pig ear treats to their dogs.
    • Several companies recalled pig ear products because they might have been contaminated with Salmonella. No single supplier, distributor, or common brand of pig ear treats has been identified that could account for all the illnesses.
    • Details on pig ear products involved with the outbreak can be found on the FDA webpage.
  • See the DHS salmonellosis fact sheet for more information on common symptoms and treatment of salmonellosis. If you have any symptoms of salmonellosis, please contact your doctor.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Consuming Foods from Outpost Natural Foods
Final Update 1/16/2020

  • The Wisconsin Department of Health Services (DHS) and local health departments investigated an outbreak of salmonellosis linked to consuming food from Outpost Natural Food locations.
  • On August 23, 2019, the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) and the City of Milwaukee Health Department suspended meat and food processing at Outpost Natural Foods located in Milwaukee at 2826 S. Kinnickinnic Ave. due to insanitary conditions. DATCP suspended the cooperative's meat establishment license and the City of Milwaukee suspended the cooperative's retail food processing activities.
  • Insanitary conditions were discovered during a routine inspection and ready-to-eat products tested positive for Salmonella.
  • Four people infected with the outbreak strains of Salmonella found at Outpost Natural Foods; three were available for interview and each reported consuming food from one of the Outpost Natural Food locations.
  • Known patient onset dates ranged from March 20-May 6, 2019.
  • All licenses have been re-instated and Outpost Natural Food is operating under Voluntary Compliance Agreement’s on each license.

Multistate Outbreak of Salmonella Infections Linked to Contact with Backyard Poultry
Final Update 11/1/19

Chickens feeding on the grass in the backyard

Salmonellosis Linked to Vegetable Trays
Final Update 7/11/19

Store bought vegetable tray

  • The Department of Health Services (DHS), the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), Minnesota Department of Health and local health departments worked with the Centers for Disease Control and Prevention (CDC), and the U.S. Food and Drug Administration (FDA) to investigate a multi-state outbreak of salmonellosis linked to consumption of certain Del Monte vegetable trays.
  • All ill patients associated with this outbreak, four in Wisconsin and one in Minnesota, reported eating a Del Monte vegetable tray purchased from a Wisconsin or Minnesota Kwik Trip location before they became ill.
  • The Del Monte vegetable trays associated with the investigation contain broccoli, cauliflower, carrots, and dill dip. It is not likely that the trays that made people sick are still on the market or still in people’s homes.
  • See the DHS salmonellosis fact sheet, P-42088 for more information on common symptoms and treatment of salmonellosis.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Cut Melons
Final Update 6/19/19

Fresh melon cut up and ready to eat

  • The Wisconsin Department of Health Services (DHS) in collaboration with 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) alerted Wisconsin consumers to a multistate outbreak of Salmonella Carrau infections linked to eating pre-cut melons sold by Caito Foods LLC.
  • One case was reported in Wisconsin and 137 people infected with the Salmonella strain were reported in nine other states.
  • On April 12, 2019, Caito Foods LLC recalled pre-cut watermelon, honeydew melon, cantaloupe, and pre-cut fruit medley products containing one of these melons supplied at the Caito Foods LLC facility in Indianapolis, Indiana.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Ground Turkey
Final Update 6/19/19

Raw ground turkey.

  • The Wisconsin Department of Health Services (DHS) and local health departments investigated four cases of salmonellosis affecting Wisconsin residents with the same strain (DNA fingerprint) of Salmonella.
  • All four of the Wisconsin patients were linked to Butterball raw ground turkey. Testing of leftover raw ground turkey received by the patients was positive for the outbreak strain of Salmonella.
  • These items were shipped to institutional and retail locations nationwide. The affected ground turkey product may have been distributed through food pantries.
  • As a result of this outbreak, Butterball recalled 78,164 pounds of raw ground turkey products. A complete list of products included in the recall can be found in the U.S. Department of Agriculture Recall notice. The products subject to recall bear establishment number “EST. P-7345” inside the USDA mark of inspection.
  • Additional information can be found on the following websites:
2018 Outbreaks

Legionnaires' Disease Associated with the University of Wisconsin (UW) Hospital in Madison
Final Update 6/4/19

Closeup of the front of a running shower head

  • The Wisconsin Department of Health Services (DHS), in collaboration with the Centers for Disease Control and Prevention (CDC), and Public Health Madison and Dane County, worked closely with UW Health on the investigation of nosocomial Legionnaires’ disease associated with the University Hospital in Madison, Wisconsin.
  • On Nov. 28, 2018, DHS was notified by a UW Health Infection Preventionist of confirmed cases of Legionnaires’ disease among patients admitted to their hospital since Oct. 31, 2018.
  • 14 cases of Legionnaires' disease were identified at University Hospital. Three patients who had been hospitalized for other serious health conditions died.
  • An environmental investigation at the hospital was completed.
  • Legionellosis in an infection caused by Legionella bacteria. There are two different types of legionellosis: Pontiac fever and Legionnaires' disease. Pontiac fever is a mild respiratory illness and Legionnaires' disease is a type of pneumonia.
    • Legionnaires' disease is not normally spread from person to person.
    • This CDC infographic outlines how Legionella bacteria is spread from water sources to people.
  • Additional information can be found on the following websites:

Salmonellosis Linked to Kellogg's Honey Smacks Cereal
Final Update 6/19/19

Bowl of dry breakfast cereal

Cyclosporiasis Linked to Salads Sold at McDonald's
Final Update 6/19/19

Bowl of salad lettuces

Salmonellosis Linked to Cut Melons
Final Update 6/19/19

Fresh melon cut up and ready to eat

  • The Wisconsin Department of Health Services (DHS) and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) alerted Wisconsin consumers to a multistate outbreak of Salmonella Adelaide infections linked to the consumption of pre-cut melons. No cases were identified in Wisconsin residents, but the recalled products were sold at locations in the state.
  • The FDA identified Costco stores in the following Wisconsin cities as having distributed the recalled pre-cut melon: Bellevue (Green Bay), Grafton, Grand Chute, Menomonee Falls, Middleton, New Berlin, Pewaukee, Pleasant Prairie, and Sun Prairie.
  • The full list of stores where this product was distributed is available on the FDA’s website.
  • No cases were reported in Wisconsin. Nationally, 77 people infected with the Salmonella strain have been reported.
  • Additional information can be found on the following websites:

Synthetic Cannabinoids (K2, Spice)
Final Update 6/19/19

Image of Synthetic Cannabinoids fact sheet "K2, Spice, Black Mamba, Fake Weed, Green Giant"

  • Case counts in Wisconsin can be found on our synthetic cannabinoid webpage.
  • The CDC is investigated this outbreak across the nation.
  • Share our one-page fact sheet on synthetic cannabinoids (PDF) . Now available in English and Spanish.
  • If you have used any of these products, and start experiencing severe, unexplained bleeding or bruising, please have someone take you to the hospital immediately or call 911.

 

Acute Flaccid Myelitis (AFM) Investigation
Final Update 6/4/19

Digital illustration of a neuron

  • The Wisconsin Department of Health Services (DHS) and local health departments (LHDs) are actively working to identify potential cases of acute flaccid myelitis (AFM). DHS is working with health care providers and the Centers for Disease Control and Prevention (CDC) during this developing situation.
  • There were nine confirmed and three probable cases of AFM in Wisconsin.
    • AFM is also called “acute flaccid paralysis with anterior myelitis” or “polio-like syndrome.” It is rare and mainly found in children. It affects the body’s nervous system, specifically the spinal cord. AFM can be caused by some viruses, environmental toxins, and genetic disorders.
    • Viruses that can cause AFM include enteroviruses (polio and non-polio) and flaviviruses, such as West Nile Virus, Japanese Encephalitis virus, or St. Louis encephalitis virus. Other viruses that may cause AFM are herpesviruses (e.g., cytomegalovirus, Epstein-Barr virus) and adenoviruses.
  • See the DHS AFM webpage for more information on common symptoms and treatment of AFM. Seek medical care as soon as possible if you notice any symptoms of AFM in you or your child, for example if your child is not using their arm or leg normally.
  • Additional information can be found on the following websites:
    • AFM Fact Sheet, P-01298 (Multiple Languages): Educational fact sheet for the general public on AFM covering signs and symptoms, treatment, and prevention.
    • About AFM: CDC webpage including information on symptoms, diagnosis, possible causes of AFM, treatment, and prevention.

E. coli O157:H7 Linked to Romaine Lettuce - Fall 2018
Final Update 1/10/19

Romaine Lettuce on white background

  • The Wisconsin Department of Health Services (DHS), Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and numerous other states investigated a multistate outbreak of E. coli O157:H7 infections.
  • This outbreak was not related to the multistate outbreak of E. coli O157:H7 infections linked to romaine lettuce that occurred earlier in 2018 (see below for Wisconsin-specific information).
  • Nationwide, 62 people from 16 states were infected with the outbreak strain of E. coli O157:H7. Illnesses started on dates ranging from Oct. 7 to Dec. 4, 2018.
  • There were 25 people hospitalized, with no deaths reported. One Wisconsin E. coli O157:H7 infection was linked to the outbreak.
  • This outbreak appears to be over as of January 9, 2019.
    • Contaminated lettuce that made people sick in this outbreak should no longer be available.
    • Epidemiologic, laboratory, and traceback evidence from the United States and Canada indicated that romaine lettuce harvested from the Central Coastal growing regions of northern and central California was the likely source of the outbreak.
  • Additional information on the following websites:

Cyclosporiasis Linked to Vegetable Trays
Final Update 9/7/18

Store bought vegetable tray

  • The Department of Health Services (DHS), the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), 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 an outbreak of cyclosporiasis linked to the consumption of Del Monte vegetable trays sold at Kwik Trip.
    • 177 cases report consuming a Del Monte vegetable tray purchased at a Kwik Trip location in Wisconsin. Most ill persons reported purchasing the tray on or after May 16, 2018. Kwik Trip voluntarily removed the trays from sale in their stores on June 8, 2018.
    • Consumers should not eat 6 oz. or 12 oz. Del Monte vegetable trays (containing broccoli, cauliflower, carrots, and dill dip) purchased at a Kwik Trip location.
    • Del Monte issued a recall of 6 oz, 12 oz, and 24 oz vegetable trays with dip. See the FDA website for full details.
  • As of Sept. 5, 2018, CDC was notified of 250 laboratory-confirmed cases of Cyclospora infection in people from 4 states who reported consuming pre-packaged Del Monte Fresh Produce vegetable trays containing broccoli, cauliflower, carrots, and dill dip.
  • Based on epidemiological data or traceback evidence, it was not possible to determine if an individual component of the vegetable trays was the likely vehicle of infection. Read the related statement from the FDA for additional information.
  • See the DHS 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:

Multistate Outbreak of Salmonella Infections Linked to Contact with Backyard Poultry
Final Update 6/14/19

Chickens feeding on the grass

  • During 2018, the Wisconsin Department of Health Services (DHS) and local health departments worked with the Centers for Disease Control and Prevention (CDC) to investigate multistate outbreaks of Salmonella infections linked to contact with backyard poultry.
    • The CDC reported that 334 people from 47 states became ill with a strain of Salmonella linked to backyard poultry during 2018. 
    • In Wisconsin, 33 laboratory-confirmed cases of Salmonella were linked to the 2018 national backyard poultry outbreak. 
    • Nationally, illness onset dates ranged from Feb. 15, 2018 to Aug. 10, 2018. Children younger than 5 years accounted for 21% of illnesses.
  • Outbreaks of Salmonella infections linked to contact with backyard poultry happen every year in the U.S. Many of these infections are preventable.  
  • More information about outbreaks associated with live poultry can be found at CDC's webpage U.S. Outbreaks of Zoonotic Diseases Spread between Animals and People.
  • More information about backyard poultry and safe handling can be found at the DHS backyard poultry webpage.

E. coli O157:H7 Linked to Romaine Lettuce - Spring 2018
Final Update 6/28/18

  • The Wisconsin Department of Health Services (DHS), the Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), and numerous other states investigated a multistate outbreak of E. coli O157:H7 infections.
  • Epidemiologic, laboratory, and traceback evidence indicated that romaine lettuce from the Yuma growing region was the likely source of this outbreak.
  • Nationwide, 210 people from 36 states were infected with the outbreak strain of E. coli O157:H7. Illnesses started on dates ranging from March 13, 2018, to May 12, 2018.
  • As of 6/28/2018, 96 people were hospitalized, with five deaths reported. Three Wisconsin E. coli O157:H7 infections have been linked to the outbreak.
2017 Outbreaks

Legionnaires’ Disease Associated with Christmas Mountain Village Resort in Wisconsin Dells
Final Update 1/16/20

Closeup of the front of a running shower head

  • The Wisconsin Department of Health Services (DHS), in collaboration with the Sauk County Health Department, and the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP), worked with Christmas Mountain Village on the investigation of three cases of Legionnaires’ disease associated with Christmas Mountain Village Resort in Wisconsin Dells, Wisconsin.
  • Legionnaires’ disease is a type of pneumonia caused by the bacteria Legionella, which can grow inside building water systems (pipes, hot water heaters, etc.).
    • Symptoms of Legionnaires’ disease can include cough, fever, chills, muscle aches, headache, and shortness of breath.
    • Legionnaires’ disease is more common in people aged 50 years and older, those who smoke, and among individuals who are at higher risk of infection, such as those with a chronic illness, respiratory disease, or a weakened immune system.
    • Legionnaires' disease is not normally spread from person to person.
    • People can get Legionnaires’ disease after breathing in small water droplets with Legionella. This CDC infographic outlines how Legionella bacteria is spread from water sources to people.
  • Christmas Mountain Village Resort is working with a water management company on testing the resort’s water for Legionella and remediation (removal of Legionella from the water system).
    • The resort is continuing to notify guests at the time of reservation and check-in.
    • Point-of-use filters have been installed on showerheads and faucets in all units of the resort. These point-of-use filters are a recommended risk-reduction measure and will stay in place until testing and completing remediation (removal of Legionella) of all units at the resort is complete.
  • People who are planning to visit Christmas Mountain Village should evaluate their risk of infection or talk to their doctor before their visit and may wish to consider postponing their visit until after remediation is complete.
  • DHS and the Sauk County Health Department continue to monitor for new cases potentially associated with the resort. People who become ill with symptoms of Legionnaires’ disease within 14 days of their stay should seek medical attention and mention the information above to their doctor.
  • Additional information can be found on the following websites:

Seoul Hantavirus
Final Update 05/26/2017

Three rats

  • During 2017, the Wisconsin Department of Health Services (DHS), Wisconsin local health departments, the Centers for Disease Control and Prevention (CDC), and other state health departments investigated an outbreak of illnesses caused by the Seoul virus, a rare type of hantavirus carried by Norway and black rats.
  • The outbreak was detected in January 2017 when two Wisconsin residents were diagnosed with Seoul hantavirus (SHV), which can cause hemorrhagic fever with renal syndrome. Norway and black rats are the only known reservoir. The investigation determined the affected individuals were in routine contact with pet rats, either owning rats as pets or operating a rattery where they regularly sold and exchanged rats with individuals and other ratteries.
  • The response efforts included tracking movement of rats between locations (ratteries, pet homes) with infected rats, coordination of hantavirus testing for rats linked to the outbreak, and follow-up with people exposed to infected rats or ratteries.
  • Nationwide, 17 laboratory-confirmed recent human cases of SHV infection were reported as part of this outbreak, including three cases in Wisconsin. Two additional Wisconsin residents were identified with evidence of past infection.
    • The outbreak investigation led to the identification of 31 infected ratteries in 11 states and Canada. This indicated that Seoul virus should be considered endemic in the U.S., and that pet rats in the U.S., including Wisconsin, can be carrying Seoul virus at any time.
    • Rat owners and breeders may wish to determine if a rat is infected prior to introducing it into their home or rattery. Commercial testing for Seoul virus is available through several laboratories. Contact your veterinarian for testing information.
  • See the DHS hantavirus fact sheet, P-42053 for more information on common symptoms and prevention of SHV. If you have any symptoms of SHV and a history of rat contact, please contact your doctor.
  • Additional information can be found on the following websites:
2016 Outbreaks

Multidrug-resistant Campylobacter Outbreak
Final Update 01/18/2018

Sleepy puppy rests in his owner's arm

  • The Wisconsin Department of Health Services (DHS), the Centers for Disease Control and Prevention (CDC), several other states, and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) investigated a multistate outbreak of multidrug-resistant (MDR) Campylobacter infections.
  • Nationwide, 113 people from 17 states were infected with the outbreak strain of MDR Campylobacter, including eight people in Wisconsin. Illnesses started on dates ranging from Jan. 12, 2016, to Jan. 7, 2018.
    • Of the 103 ill people with information available, 23 (22%) were hospitalized.
    • This outbreak was linked to contact with pet store puppies. Of those who became ill, 90% had a link to puppies at, or from, a Petland store, or had contact with with a person who became sick after contact with a puppy from a Petland store.
  • In Wisconsin, eight people became sick and two were hospitalized.
  • All puppies and dogs can carry Campylobacter bacteria. Because of this, it is especially important to wash your hands thoroughly with running water and soap for at least 20 seconds every time you touch dogs, their poop, or their food. Adults should supervise handwashing for young children. Please see our Handwashing After Animal Contact flyer, P-01699 for more information about how to prevent these infections.
  • See the DHS campylobacteriosis fact sheet, P-42045 for more information on common symptoms and treatment of campylobacteriosis. If you have any symptoms of campylobacteriosis, please contact your doctor.
  • Additional information can be found on the following websites:

Elizabethkingia anophelis
Final Update 05/03/2016

Elizabethkingia Anophelis - culture plate

  • The Wisconsin Department of Health Services (DHS) and the Centers for Disease Control and Prevention (CDC) investigated an outbreak of bacterial infections caused by Elizabethkingia anophelis.
  • There were 67 total cases reported to DHS during this outbreak. Of those cases, 63 were confirmed, and four tested positive for Elizabethkingia but will never be confirmed as the same strain of Elizabethkingia anophelis because the specimens were not available for testing.
  • The majority of patients who acquired these infections were over 65 and all patients had a history of at least one underlying serious illness.
  • Counties with confirmed cases include Columbia, Dane, Dodge, Fond du Lac, Jefferson, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, Waukesha, and Winnebago.
  • There were 18 deaths among individuals with confirmed Elizabethkingia anophelis infections and an additional one death among possible cases for a total of 19 deaths. It was not determined if these deaths were caused by the infection or other serious, pre-existing health problems. Counties where deaths occurred are: Columbia, Dodge, Fond du Lac, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, and Waukesha.
  • DHS quickly identified effective antibiotic treatment for Elizabethkingia, and alerted health care providers, infection preventionists, and laboratories statewide. Initial guidance was sent on January 15, 2016, and there was a rapid identification of cases and health care providers were able to treat and improve outcomes for patients.
  • Additional information can be found on the following websites:
2015 Outbreaks

Salmonella Heidelberg
Final Update 02/12/2018

Calf laying on hay

Last Revised: January 21, 2020