According to the Illinois Department of Public Health the first batch of mosquitoes to test positive for West Nile virus in 2022 have been found in Roselle, in DuPage County.
The positive batch was collected on May 24. No human cases of West Nile virus have been reported so far this year.
“This is the time of year when West Nile virus make its annual appearance,” said IDPH Acting Director Amaal Tokars. “We remind everyone -- and especially older people and those with weakened immune systems -- to take precautions to protect themselves from mosquitoes and the viruses they carry by wearing insect repellent and eliminating standing water around their home where mosquitos breed.”
People older than 60 and individuals with weakened immune systems are at higher risk for severe illness from West Nile virus.
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According to the state health department, West Nile virus is transmitted through the bite of a Culex pipiens mosquito, commonly called a house mosquito, that has picked up the virus by feeding on an infected bird.
"Symptoms of West Nile in humans include fever, nausea, headache and muscle aches, with symptoms lasting from a few days to a few weeks," a release from the Illinois Department of Public Health says. "However, four out of five people infected with West Nile virus will not show any symptoms. In rare cases, severe illness including meningitis, encephalitis, or even death, can occur."
The state health department says that monitoring West Nile virus in Illinois includes laboratory tests for mosquito batches, dead crows, blue jays, robins and other perching birds, as well as testing sick horses and humans with West Nile virus-like symptoms.
People who see a sick or dying crow, blue jay, robin or other perching bird should contact their local health department.