The first case of West Nile virus in humans in Wisconsin was reported in 2002. In 2018, Wisconsin had 33 probable and confirmed cases of West Nile virus. Since 2002, on average, 19 cases of West Nile virus are reported each year. West Nile virus is preventable.
You can see the statewide data for West Nile virus in the table below. For information on national data, visit the Centers for Disease Control and Prevention (CDC) Statistics and Epidemiology page for West Nile virus.
Case numbers are updated weekly during mosquito season.
2019 Wisconsin Summary Data
|Counties reporting WNV activity||5|
* Probable cases have presumptive positive laboratory results without confirmatory testing at CDC.
** The deaths are included among the confirmed and probable cases.
West Nile Virus Data
West Nile Virus Cases in Wisconsin (2002-2018)
Cases Reported by Month and Age
Month of Illness Onset
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