West Nile virus arrives in Portage County

PORTAGE COUNTY—The first case of West Nile virus in a human patient in 2025 has been confirmed in Portage County. Local health officials are advising residents to continue to protect themselves against mosquito bites. West Nile virus has been detected in other areas of Wisconsin, with mosquitoes, humans and animals infected with the virus.
West Nile virus is spread to humans through the bite of an infected mosquito, and cannot be spread from person to person. Mosquitoes become infected by feeding on infected birds.
In Wisconsin, West Nile virus is most common in Aug. and Sept., but is present in mosquitoes anytime they are active.
Portage County Health and Human Services advises that 80% of people who are infected with West Nile virus do not get sick, and those that do experience mild symptoms such as fever, headache, muscle ache, rash, and fatigue. Less than 1% of those infected develop serious symptoms that include high fever, muscle weakness, stiff neck, disorientation, mental confusion, tremors, confusion, paralysis, and coma. Those most at risk of experiencing severe symptoms include older adults those with compromised immune systems.
To avoid illness, it is recommended to reduce exposure to mosquitoes and eliminate mosquito breeding sites. Mosquitoes will no longer be active once there is a hard frost that occurs once the temperature reaches 28 degrees for at least four consecutive hours.