Outbreaks in Wisconsin

Outbreaks and Investigations

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

Legionnaires' Disease Associated with the University of Wisconsin (UW) Hospital in Madison
Updated 1/11/19

  • Closeup of the front of a running shower headThe Wisconsin Department of Health Services (DHS), in collaboration with the Centers for Disease Control and Prevention (CDC), and Public Health Madison and Dane County, is working 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.
  • As of Jan. 11, 2019, 14 cases of Legionnaires' disease have been identified at University Hospital. Three patients who had been hospitalized for other serious health conditions have died. 
  • An environmental investigation at the hospital is ongoing.
  • 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:

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

  • Cow milking facilityThe 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:

Acute Flaccid Myelitis (AFM) Investigation
Updated 12/6/18

Digital illustration of a neuron

  • The 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.
  • As of Dec. 6, 2018, there have been nine confirmed 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.

Salmonellosis Linked to Kellogg's Honey Smacks Cereal
Updated 9/5/18

Bowl of dry breakfast cereal

Cyclosporiasis Linked to Salads Sold at McDonald's
Updated 8/3/18

Multistate Outbreak of Salmonella Infections Linked to Contact with Backyard Poultry
Updated 7/27/18

  • Chickens feeding on the grassThe Department of Health Services (DHS) and local health departments are working with the Centers for Disease Control and Prevention (CDC) to investigate a multistate outbreak of Salmonella infections linked to contact with backyard poultry.
  • As of July 13, 2018, the CDC reports 212 people infected with an outbreak strain of Salmonella. Children younger than 5 years account for 26% of illnesses.
  • In Wisconsin, 18 laboratory-confirmed cases of Salmonella have been linked to the national live poultry outbreak.
  • Outbreaks of Salmonella infections linked to contact with backyard poultry happen every year in the U.S. Many of these infections are preventable. Please see our Backyard Poultry flyer for more information about how to prevent these infections.

Salmonellosis Linked to Cut Melons
Updated 6/19/18

Fresh melon cut up and ready to eat

  • DHS and the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP are alerting Wisconsin consumers to a multistate outbreak of Salmonella Adelaide infections linked to the consumption of pre-cut melons. At this time, no cases have been identified in Wisconsin residents, but the recalled products were sold at locations in the state.
  • The FDA has 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 distributing this product is available on the FDA’s website and may expand to include other stores as the investigation continues. Consumers who have purchased recalled pre-cut melon from these stores, including fruit salad mixes with pre-cut melon, should not eat it and throw it away.
  • To date, no cases have been reported in Wisconsin, but public health officials continue to monitor for cases. Nationally, 60 people infected with the Salmonella strain have been reported in other Midwest states. States that have reported illnesses include Illinois (six cases), Indiana (11 cases), Michigan (32 cases), Missouri (10 cases), and Ohio (one case).
  • Additional information can be found on the following websites:

Synthetic Cannabinoids (K2, Spice)
Updated 6/26/18

  • Updated case counts in Wisconsin can be found on our synthetic cannabinoid webpage.
  • The CDC is investigating this outbreak across the nation.
  • Share our one-page fact sheet on synthetic cannabinoids (PDF) . Now available in English and Spanish.
  • If you have purchased any of these products in the past month, do not use it. 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. Image of Synthetic Cannabinoids fact sheet "K2, Spice, Black Mamba, Fake Weed, Green Giant"


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

Last Revised: January 18, 2019