With the arrival of summer the Illinois Department of Public Health (IDPH) is reminding the public about the ongoing mosquito season and the potential threat of West Nile virus.
Thus far, 11 virus-positive mosquito pools and 10 positive birds have been reported in 13 counties, including Cook, Douglas, Fulton, Kane, Champaign, LaSalle, Morgan, Hancock, Whiteside, Williamson, Washington, Woodford and Winnebago counties.
The first mosquito batches of the year were discovered in mid-May, which is two weeks earlier than a typical year.
If a mosquito, bird, horse or human tests positive for the virus, counties are classified as West Nile positive.
West Nile virus testing involves the collection of mosquitoes and sick and dead birds by local health departments. Horses and humans exhibiting virus-like symptoms are also subjected to testing.
If residents come across sick perching birds such as the blue jay, cardinal, robin or crow, they should get in touch with their local county or city health agency to assess if the bird should be collected for testing.
Illinois hasn’t recorded any human cases this year, which is good news considering the significant increase in cases reported in 2023 and 2022. Six human fatalities were attributed to West Nile virus in 2023, compared to seven in 2022.
In Illinois, 97 local health departments receive $2.8 million from IDPH for vector surveillance and mosquito control efforts. The IDPH uses its funding to purchase and apply larvicide, while also investigating areas where mosquitoes breed and addressing complaints about nuisance mosquitoes. Municipal governments and news media also partner with the organization for West Nile prevention and education.
“West Nile Virus can lead to serious illness, especially for our Illinois seniors and people with weakened immune systems,” IDPH Director Dr. Sameer Vohra said in a press release. “With the virus appearing earlier this year following a milder winter and spring, I urge everyone to fight the bite in their communities. Please reduce exposures, wear insect repellent while outdoors, and report any standing water around your community where mosquitoes can breed.”
The virus is passed through the bite of a Culex mosquito that becomes infected after feeding on a bird with the virus. Symptoms might consist of fever, headache and muscle aches accompanied by nausea. The symptoms can persist for several days to several weeks. The majority of West Nile virus infections are asymptomatic.
In some uncommon instances, humans may develop severe conditions such as encephalitis, meningitis, sometimes dying. The risk is increased for individuals over 60 or with weakened immune systems.
The IDPH tells the public to practice the three “R’s”: reduce, repel and report. Having well-fitted screens on doors and windows is essential. It is also important to keep doors and windows shut. In addition residents should get rid of, or refresh, any standing water where mosquitoes reproduce.
When outside it is recommended for people to wear long pants, a light-colored, long-sleeved shirt, shoes, socks and an EPA-registered insect repellent that contains DEET, oil of lemon eucalyptus, para-menthane-diol (PMD), 2-undecanone or picaridin.
Residents should be sure to report any instances of stagnant water that has been sitting for longer than a week, including flooded yards, fields and roadside ditches. Larvicide can be added to water sources by local health departments and city governments to eradicate mosquito larvae.
Find updates on reported cases on the IDPH West Nile surveillance website. Additional information about the West Nile virus can be found on the IDPH website.
