It's the county's first case in 2023. The Rock Island County Health Department says no cases in humans have been reported.
People get the virus from mosquitos that fed on an infected bird.
Summer weather increases the risk of exposure. People can lessen the risk by minimizing time spent around mosquitos and using repellant.
The county tests mosquitos and dead birds for West Nile virus. It encourages the public to call the health department if they find a sick or dying bird that has not been hit by a car or attacked by an animal.
Symptoms in humans include fever, nausea, headache and muscle aches that can last for days or weeks.
Most people won't show any symptoms. But it can be dangerous for people older than 50 or who are immunocompromised.