The Illinois Department of Public Health (IDPH) has confirmed the first human case of West Nile virus in the state this year, as reported by the U.S. Centers for Disease Control and Prevention. The infected individual, a resident of southern Illinois, was hospitalized. This marks the earliest in the year that a human case has been identified in Illinois since 2016, indicating a potentially active season ahead.
Although this is the first confirmed human case, the virus has already been detected in mosquito populations across 19 Illinois counties, with the first positive sample found in Rockford on May 9. The IDPH regularly tests mosquito batches for West Nile and other mosquito-borne illnesses. In 2023, West Nile was identified in 72 out of Illinois’s 102 counties, showing its widespread presence in the state.
IDPH Director Dr. Sameer Vohra emphasized the importance of early precautions, especially for seniors and people with weakened immune systems, who face higher risk. While most people infected with West Nile show no symptoms, about 20% may develop serious illnesses, and in 2023, the state saw 69 human cases and 13 related deaths. The department advises residents to protect themselves with mosquito repellents and ensure windows and doors are properly screened.
To further reduce risk, residents should eliminate standing water around their homes, as mosquitoes need stagnant water to breed. The IDPH also suggests reporting unmanageable standing water to 311. West Nile virus is transmitted primarily by the Culex house mosquito and is not usually spread between humans. Although bites are most common in the evening, they can happen at any time, making constant vigilance important during mosquito season.
This post is based on reporting from the Chicago Tribune.