OREGON, Ill. (AP) _ Health officials say a dead bird found in Ogle County has tested positive for West Nile virus.

The Ogle County Health Department announced the news late last week.

Mosquitoes become infected with West Nile when they feed on an infected bird, then can spread the virus to humans and animals when they bite. While most people with West Nile virus have no clinical symptoms of illness, some may become ill in as little as 3 days. In the most extreme cases, symptoms include encephalitis or meningitis and can be fatal.

Last year, four people in Illinois died from West Nile virus.

In Chicago, health officials say its annual prevention program includes putting larvicide in catch basins to limit the number of mosquitoes carrying the virus.