Prairie State Wire

The Illinois Department of Public Health (IDPH) has announced the first human case of West Nile virus (WNV) in Illinois for 2024. The individual, who is in their 60s and resides in suburban Cook County, began showing symptoms in mid-June. Although commercial testing and clinical symptoms indicate a case of WNV, confirmatory testing by the Centers for Disease Control and Prevention (CDC) is pending.

IDPH is monitoring positive batches of birds and mosquitoes through its West Nile virus dashboard, reporting that 33 counties in Illinois have shown positive results this year. This serves as an early warning of WNV presence in these areas.

"Summer in Illinois means mosquitos, and these mosquitos increase our risk of contracting vector-borne illnesses like West Nile Virus," said IDPH Director Dr. Sameer Vohra. "We encourage all Illinois residents to ‘Fight the Bite' and protect themselves and their loved ones from insect bites that can cause potentially serious illnesses."

In 2023, there were 119 human cases of WNV reported in Illinois, an increase from 34 cases in 2022. There were six deaths attributed to WNV last year compared to seven in 2022. The first human case of WNV in Illinois for 2023 occurred in late June.

IDPH supports mosquito control efforts statewide by providing $2.8 million to local health departments for vector surveillance and control activities. These efforts include purchasing and applying larvicide, collaborating with local governments and media on prevention education, investigating mosquito production sites, and addressing nuisance mosquito complaints. Local health departments also collect mosquitoes and sick or dead birds for WNV testing.

West Nile virus is transmitted through the bite of a mosquito that has fed on an infected bird. Common symptoms include fever, nausea, headache, and muscle aches lasting from a few days to weeks. Most people infected will not show symptoms; however, severe illness can occur in rare cases, including brain infections such as meningitis or encephalitis, paralysis, or death. Individuals over 50 years old and those who are immunocompromised are at higher risk for severe illness.

There is no specific treatment or vaccine for WNV currently available; thus it is crucial to minimize exposure risks.

IDPH advises the public to follow the three "R's" - reduce, repel, and report:

- **REDUCE**: Ensure doors and windows have tight-fitting screens; repair any tears or openings; eliminate standing water sources where mosquitoes can breed.

- **REPEL**: Wear protective clothing outdoors; use EPA-registered insect repellents containing DEET or other recommended ingredients.

- **REPORT**: Report stagnant water locations to local health departments or city governments which may apply larvicide to kill mosquito larvae.

Surveillance for West Nile virus includes reporting symptomatic individuals and conducting laboratory tests on environmental samples such as mosquito batches and dead birds. People observing sick or dying birds should contact their local health department for potential testing.

Additional information on West Nile virus in Illinois can be found at the IDPH website.