NYC Health Department Detects First Person With West Nile Virus in 2026

NYC Health Department Detects First Person With West Nile Virus in 2026

West Nile Virus Has Been Detected in Mosquitoes in All Five Boroughs Since June; Mosquitoes Carrying West Nile Virus Are Present in New York City Every Year From June Through October

West Nile Virus Is Spread to People Through the Bite of an Infected Mosquito and Cannot Spread From Person to Person

New Yorkers Should Take Precautions to Prevent Mosquito Bites

August 19, 2026 - The New York City Health Department is reporting that a person who lives in New York City has contracted West Nile virus after spending time outdoors in areas in New York City and several locations outside the city. This is the first reported case in New York City this year. Nationally, there have been 222 human cases of West Nile virus so far this year, according to the Centers for Disease Control (CDC), primarily in Arizona, Texas, and California.

West Nile virus is spread to people through the bite of an infected mosquito and cannot spread from person to person. Mosquitoes carrying West Nile virus are present in New York City every year from June through October, with peak activity typically during August and September. The Health Department intensified mosquito surveillance and expanded control efforts after the virus was detected in nearly twice as many mosquito pools as last year and across all five boroughs since June. The Health Department is encouraging New Yorkers to take precautions to reduce the risk of mosquito bites.

Most people infected with the virus have no symptoms, though some may develop fever along with headache, muscle aches, rash, and fatigue. About 1 in 150 people can develop a serious and potentially fatal illness of the brain and spinal cord called West Nile neuroinvasive disease, leading to changes in mental status and muscle weakness requiring hospitalization. Those most at risk are people 60 years and older or who have a weakened immune system. Anyone with symptoms of West Nile virus should contact their healthcare provider. While most patients go on to fully recover, some continue to have health problems months after infection or permanent disability.

"West Nile virus is spread by mosquito bites and cannot spread from person to person. The good news is it's preventable. With mosquito season in full swing, we're encouraging New Yorkers to take extra precautions to minimize the risk of mosquito bites," said NYC Health Commissioner Dr. Alister F. Martin. "The steps to protect yourself are simple: wear insect repellent, cover up during dawn and dusk, and get rid of standing water around your home. All New Yorkers should take these precautions seriously, especially older New Yorkers and those with a weakened immune system."

The Health Department operates one of the nation's most comprehensive mosquito surveillance and control programs, monitoring mosquito populations throughout all five boroughs from spring through fall. Each week, trained staff collect mosquitoes from hundreds of locations across the city. The mosquitoes are grouped into samples, or "pools," that are tested together for the presence of West Nile virus. The Health Department conducts targeted control efforts when data indicate an increased risk of disease transmission.

Since July, the Health Department has conducted eight targeted mosquito control operations in neighborhoods where West Nile virus-positive mosquito pools were detected. These operations typically reduce adult mosquito populations by 70% and decrease West Nile virus-positive mosquito pools by more than 85%, helping to reduce the risk of human infection. Information about completed and upcoming mosquito control operations is available at nyc.gov/mosquito.

The Health Department has identified over 1,000 West Nile virus-positive mosquito pools citywide this year. The first positive mosquito pools this year were detected on June 16. The Health Department conducted its first aerial larviciding operation of the year from June 8 to June 10. The CDC is reporting higher than usual West Nile virus activity in other parts of the country as well, primarily in Arizona. However, it is difficult to compare New York City's findings with other parts of the country given the City's robust mosquito surveillance.

West Nile virus was first detected in New York more than 25 years ago. From 2012 to 2021, an average of 16 people per year were diagnosed with West Nile neuroinvasive disease. From 2022 to 2025, the average increased to 31 people per year. Most New Yorkers diagnosed with West Nile virus report that they did not use repellent or take other precautions to prevent mosquito bites.

New Yorkers can significantly reduce their risk by taking a few simple precautions:

• Know your risk for severe illness from West Nile virus
• • The risk of severe illness increases with age. For example, people 65 years and older are three times as likely to develop neurologic illness as people younger than 65 years.
  • People with certain chronic medical conditions such as cancer, diabetes, high blood pressure (hypertension), or kidney disease are at higher risk of severe illness.
  • People with a weakened immune system, including those who take medications that weaken the immune system, are at higher risk of severe illness. For example, rituximab, ocrelizumab, or similar medications, used to treat cancers, autoimmune diseases, and inflammatory conditions or prevent rejection of transplanted organs, weaken the immune system.
• Reduce your risk of bites
• • Limit outdoor activities during dawn and dusk, when the mosquitoes that transmit West Nile virus are generally most active.
  • Use an EPA-registered insect repellent containing DEET, picaridin, IR3535, or oil of lemon eucalyptus, and offer it to older neighbors and relatives. Follow the product label. Oil of lemon eucalyptus should not be used on children younger than age 3.
  • Wear long-sleeved shirts, long pants, socks, and shoes when spending time outdoors in areas with mosquito activity.
• Keep mosquitoes out
• • Install and repair window and door screens.
• Prevent mosquito breeding
• • Empty standing water at least once each week from buckets, flowerpots, birdbaths, children's toys, tarps, plant saucers, clogged gutters, and other containers.
  • Maintain swimming pools, hot tubs, and ornamental ponds by keeping them clean, chlorinated, covered, or properly drained when not in use.

You can report chronic standing water in private or public locations online or by calling 311. You can report water in the street caused by a street defect or a clogged catch basin online or by calling 311.

For more information about West Nile virus, mosquito prevention, and the Health Department's mosquito control program, visit nyc.gov/health/wnv or call 311.

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