Routine testing has identified the first batch of mosquitoes for West Nile virus in Jackson County this year.
The Jackson County Health Department reports mosquitoes were collected on Friday near Murphysboro.
Health officials say one out of five people who are bitten by an infected mosquito will become sick, with symptoms such as fever, nausea, headache and body aches within two weeks of the bite.
In rare cases, people may develop encephalitis or meningitis. Death is possible in extreme cases.
