CHICAGO — The Illinois Department of Public Health (IDPH) is reporting the first confirmed human case of West Nile virus in Illinois for 2018.

A Chicago resident in her 60s became ill in mid-May. IDPH Director Nirav D. Shah says because the case occurred earlier in the season than is typically seen in human cases of West Nile virus in Illinois, IDPH has requested additional testing by the Centers for Disease Control and Prevention and confirmation was received Tuesday.

Shah says West Nile virus can cause serious illness in some people so it’s important to take precautions like wearing insect repellent and getting rid of stagnant water around your home.

The first human case of West Nile virus in 2017 was reported on July 20, 2017.

Last year, 63 counties in Illinois reported a West Nile virus positive mosquito batch, bird and/or human case. For the 2017 season, IDPH reported 90 human cases (although human cases are under reported), including eight deaths.

West Nile virus is transmitted through the bite of a Culex pipiens mosquito, commonly called a house mosquito, which 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 60 and individuals with weakened immune systems are at higher risk for severe illness from West Nile virus.