Health officials in Onondaga County, in central New York, report the first human case of West Nile virus (WNV) infection in 2026.
The patient is an elderly adult residing in Liverpool, suburb of Syracuse. The individual was hospitalized, has since been discharged, and has recovered.
West Nile virus is transmitted through the bite of an infected mosquito and is considered endemic in Central New York,” said Onondaga County Health Commissioner Dr. Kathryn Anderson. “Historical trends indicate that West Nile, Eastern Equine Encephalitis, and other mosquito‑borne viruses may be present in the region each year. It remains important for the public to take routine precautions to prevent mosquito bites throughout the summer and fall, until the first frost.”
West Nile virus (WNV) is a mosquito-borne flavivirus that causes mild to severe illness. It was first identified in Uganda in 1937. WNV was first introduced to the United States in 1999 in New York.
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The virus is now considered endemic in the U.S., with annual epidemics in some parts of the country, peaking in the late summer months.
West Nile virus is most commonly spread to people through the bite of an infected mosquito.
Most people infected with West Nile virus do not develop any symptoms. Symptoms usually start 2–6 days after being bitten by an infected mosquito.
Some people develop mild illness with flu-like symptoms, such as fever with headache or 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.
Some people develop severe illness, which can affect the central nervous system or illness that results in hospitalization or death. Symptoms can include high fever, headache, neck stiffness, stupor, disorientation, muscle weakness, and more. Recovery from severe illness can take several weeks or months. Some effects may be permanent.
The best way to protect yourself and your loved ones from West Nile virus is to prevent mosquito bites. No licensed vaccines or medicines are available to prevent West Nile.
Use an insect repellent registered with the Environmental Protection Agency.
Wear long, loose-fitting shirts and pants so it is harder for mosquitoes to bite your skin.
Avoid being outside between dusk and dawn when the mosquitoes that spread West Nile virus are most active.
Use screens on windows and doors or air conditioning, if available, to keep mosquitoes outside.