WALWORTH COUNTY — The Wisconsin Department of Health Services, City of Milwaukee Health Department and Walworth County Department of Health and Human Services are jointly investigating a case of measles confirmed in a person who traveled through Milwaukee Mitchell International Airport to Walworth County.
There are no known public exposure locations in Walworth County at this time, but officials didn’t reveal which community.
The case is linked to a confirmed case in another state, and comes as DHS’ Wisconsin Wastewater Monitoring Program also detected measles in untreated wastewater collected in Walworth County. This is the first detection of measles in wastewater in Wisconsin.
The case was exposed to measles out of state and is not linked to current confirmed cases in Waukesha County and Dane County. Due to privacy concerns, no additional personal identifying or health information will be released by DHS.
Health officials are jointly working to identify and notify people who may have been exposed to the measles virus. Health officials will reach out directly to individuals identified as close contacts to the individual.
The investigation has identified a public location and time where people may have been exposed:
People who traveled on Flight WN 266 from Phoenix to Milwaukee Mitchell International Airport (5300 S Howell Ave, Milwaukee, WI, 53207) or were present at Milwaukee Mitchell International Airport on January 29, 2026 during the time period of 10:31 p.m. to 12:31 a.m. may have been exposed to measles.
If additional public exposure locations are identified, they will be updated on the DHS Outbreaks and Investigations webpage.
Measles is a highly contagious disease that can be spread from person to person through the air and can stay in the air for two hours after a sick person coughs or sneezes. It is so contagious that if one person gets it, up to 90% of the people around them may also become infected if they are not vaccinated.
Symptoms of measles typically appear approximately 10 to 21 days after exposure, 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.
Measles can cause serious health complications, including pneumonia, brain damage, and deafness, and can sometimes be deadly. One in four people who get measles in the United States will be hospitalized.
Anyone developing symptoms of measles should stay home (do not go to work, school, shopping, or use public transportation) and call their doctor’s office or clinic before visiting so they can take precautions to ensure other patients are not exposed to the virus.
Measles can be prevented with the measles, mumps, rubella vaccine (MMR). Two doses of the measles vaccine are 97% effective at preventing the disease. DHS encourages all Wisconsinites to check their vaccination status to make sure they and their family are protected from measles. In general, people born before 1957 are considered immune and do not need a vaccine. All other adults without laboratory evidence of immunity should have at least one dose of measles-containing vaccine, and children should have two doses. Find more information about who should get a measles vaccine on the DHS measles webpage.
People can check the Wisconsin Immunization
Anyone who is not vaccinated against measles can get vaccinated at their regular health care provider, local clinic, or pharmacy. Local health departments can help determine what vaccines are needed. Get free, confidential assistance finding a doctor or clinic by dialing 211. Anyone who is pregnant, has children under the age of 12 months, or is otherwise not able to receive the MMR vaccine can contact their doctor or community clinic for guidance.
Find more information on the DHS measles webpage.
This is an ongoing investigation. Any updates to public exposure locations will be shared broadly and be posted to the DHS Outbreaks and Investigations page.