Wisconsin state health officials have reported the first human West Nile virus (WNV) of the year in a Dane County resident.

Wisconsin map/National Atlas of the United States
Wisconsin map/National Atlas of the United States

The majority of WNV human cases in the state occur during the months of August and September. However, the risk of contracting WNV and other mosquito-borne illnesses is present anytime mosquitoes are active, so it is important for people to be vigilant about preventing mosquito bites throughout the summer and early fall.

WNV is spread to people through the bite of an infected mosquito and is not transmitted person to person.

The chances of a person contracting WNV are very low and most people infected with West Nile virus will not have any symptoms. Those who do become ill may develop a fever, headache, and rash that lasts a few days. Symptoms typically begin between three to 15 days after being bitten by an infected mosquito. In rare cases, WNV can cause severe disease with symptoms such as disorientation, tremors, convulsions, paralysis, inflammation of the brain, and coma. Older adults and people with weakened immune systems are at an increased risk of severe disease from the virus.

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There is no specific treatment for West Nile virus other than to treat symptoms. If you think you have West Nile virus infection, contact your healthcare provider.

In 2017, 51 human cases of WNV were reported in Wisconsin, the highest number since 2012. Eight of these cases occurred in Dane County, which was the highest number ever reported in the county.