DOUGLAS COUNTY — The Illinois Department of Public Health (IDPH) is reporting the first bird to test positive for West Nile virus in Illinois for 2016.

Douglas County Health Department employees collected the blue jay on May 20, 2015, in Arcola Township.

West Nile virus is transmitted through the bite of what is commonly called a house mosquito that has picked up the virus by feeding on an infected bird.

Common symptoms include fever, nausea, headache and muscle aches. Symptoms may last from a few days to a few weeks.

However, four out of five people infected with West Nile virus will not show any symptoms.

In rare cases, severe illness including meningitis or encephalitis, or even death, can occur. People older than 50 and immunocompromised individuals are at higher risk for severe illness from West Nile virus.

The first West Nile virus positive result in 2015 was a mosquito batch in St. Clair County collected on May 26, 2015. Last year, 64 counties in Illinois reported a West Nile virus positive mosquito batch, bird and/or human case.

For the 2015 season, IDPH reported 77 human cases (although human cases are underreported), including nine deaths. No human cases of West Nile virus have been reported so far this year.

While Zika virus is also primarily transmitted through the bite of a mosquito, the main type of mosquito that carries Zika virus is different and is rarely found in Illinois.