West Nile Virus
Mosquito season underway. First WNV-positive mosquito pools detected in Nassau and Suffolk counties. Human case season peaks August-September.
What is it?
West Nile Virus (WNV) is a mosquito-borne virus present in New York State every summer. The vast majority of infected people experience no symptoms or mild flu-like illness. A small fraction develop serious neurological disease.
How it spreads
Transmitted by the bite of infected Culex mosquitoes, which are most active from dusk to dawn. Not spread person-to-person. Rarely transmitted through blood transfusion, organ transplant, or from mother to baby.
Symptoms
Most people (80%) have no symptoms. About 20% develop West Nile Fever: headache, body aches, fever, fatigue, and sometimes rash. Less than 1% develop serious neurological illness (meningitis or encephalitis).
Who is at risk?
Everyone is at risk of infection during mosquito season. Adults over 50 and immunocompromised individuals are at higher risk for severe neurological disease.
What you can do
Surveillance data updated from government sources daily or weekly. Threat level reflects current wastewater signal or clinical reports.
This information is for general public health awareness and is not a substitute for professional medical advice, diagnosis, or treatment.