State and local health officials are reminding residents to protect themselves against mosquito bites. They’re reporting the state’s first confirmed human case of West Nile virus this year, diagnosed in a Washington County resident during routine screening of blood donations. Screening of blood donated by the patient yielded a positive result for the genetic material of West Nile virus, and the Blood Center of Wisconsin destroyed all of the blood and blood products from this donation to prevent the donated blood from entering the blood supply. The patient later reported ill with mild West Nile-like virus symptoms.
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 may begin between 3 to 15 days after being bitten by an infected mosquito. In rare cases, WNV can cause severe disease with symptoms such as muscle weakness, stiff neck, disorientation, tremors, convulsions, paralysis and coma. Older adults and people with compromised immune systems are at an increased risk of severe disease from the virus.
Blood banks have been screening blood donations for West Nile virus since 2003 to keep the blood supply safe.