Hamilton County Public Health (HCPH) has confirmed the county’s first human case of West Nile virus of 2025 in Sycamore Township. Officials say a mosquito carrying the virus likely bit the individual.
What happened?
Hamilton County Public Health (HCPH) was notified of the suspected case on Aug. 28. At that time, HCPH began consulting with relevant medical providers and health agencies, including the Ohio Department of Health (ODH) and the Centers for Disease Control and Prevention (CDC). HCPH reviewed the patient’s recent activities and medical records, and the CDC performed confirmatory testing on a sample from the patient. The CDC confirmed the locally acquired case of West Nile virus on Sept. 22.
Earlier this summer, HCPH had shared information with the public and media about mosquito samples that were confirmed as positive for carrying West Nile virus: July 7 in Wyoming, July 22 in Anderson Township and July 31 in Green Township. There were no human cases of West Nile in Hamilton County at the time those mosquito samples were confirmed.
What is West Nile virus?
West Nile virus is a mosquito-borne illness that affects the central nervous system. Infected mosquitoes spread the virus to humans through their bites; it is not contagious. In Southwest Ohio, mosquito season typically runs from spring through October, with peak activity occurring in August and September.
People with mild cases of West Nile virus typically experience flu-like symptoms such as fever, headaches, body aches, joint pain, vomiting, diarrhea or rash. Most people with mild illness recover completely, but fatigue and weakness can last for weeks or months.
Most people who are bitten by an infected mosquito will not become sick, but people with weakened immune systems, with certain chronic medical conditions or who are over age 50 are at risk for severe illness or even death. People who experience severe symptoms should see a doctor as soon as possible.
How to protect against mosquito-borne illnesses
Mosquitoes remain active until temperatures drop below 50°F or after the first frost. Until then, you can take simple steps to protect yourself and your family.
Drain, dunk, protect:
- Drain: Eliminate standing water that collects in pools, birdbaths, toys and playsets, open containers, wheelbarrows, old tires, gutters and other vessels – all places where mosquitoes tend to breed.
- Dunk: Buy larvicide or “dunks” to kill mosquito larvae in standing water that cannot be drained.
- Protect: Avoid being outdoors during peak mosquito times (dusk and dawn), especially in humid or wooded spaces. Wear light-colored, loose-fitting clothing, and apply mosquito repellents to your skin according to product instructions.
Read HCPH’s fact sheets: Complete mosquito-prevention tips can be downloaded from the fact sheets Mosquito Bite Prevention & Control Around the Home and Mosquito Borne Diseases & Travel Recommendations.
Review international travel warnings: Planning a trip to a high-risk country? The CDC’s Travelers’ Health webpage features important health notices and provides geographically relevant information on mosquito-borne diseases and other health concerns.
Speak with your healthcare provider: Ask about recommended or required vaccines for international travel.
