Health Department Studies First Human Circumstances of West Nile Virus for 2025 Season

West Nile Virus Has Been Detected in Mosquitoes in All Five Boroughs; Two People with West Nile Virus Disease Have Been Reported

New Yorkers – Especially People 55 and Older and Those with Weakened Immune Systems – Should Take Precautions to Prevent Mosquito Bites

August 22, 2025 — The Health Department at the moment introduced that West Nile virus illness has been reported in two New Yorkers, each residents of Queens. The virus has been detected in mosquito swimming pools throughout all 5 boroughs since July. Mosquitoes contaminated with West Nile virus are sometimes current in New York City from May by October, with peak exercise throughout August and September. Infected mosquitoes can unfold West Nile virus to folks by a chew. One particular person was identified with West Nile fever, was briefly hospitalized, and has since been discharged. The second particular person was identified with West Nile neuroinvasive illness and is at present hospitalized with encephalitis, an an infection within the mind. In addition, the virus was detected in blood donations from two people, one a resident of Brooklyn the opposite of Staten Island. Recent stories of two extra people (each from Brooklyn) with doable West Nile virus illness are underneath investigation.

“West Nile virus can cause serious illness, especially among people over 55 and with weakened immune systems,” mentioned Acting Health Commissioner Dr. Michelle Morse. “The Health Department’s vector surveillance and control program helps identify and reduce our risk, but there are simple things you can do to protect yourself and your loved ones . Use an EPA-registered repellent and wear long sleeve shirts and pants — especially at dawn and dusk when mosquitoes that transmit the virus are active. Eliminate standing water so mosquitoes can’t breed, and make sure you have intact screens on your doors and windows. The virus has been detected in mosquitoes across the city — visit the online map.”

The Health Department routinely traps and checks mosquitoes from throughout New York City. Once trapped, as much as 50 mosquitoes are batched collectively and examined as a single pattern or “pool.” As of August 22, there have been 988 constructive mosquito swimming pools throughout the 5 boroughs this season, lower than what was reported right now final 12 months. The Health Department is treating components of the City with mosquito exercise. Ten adulticiding spray operations, 3 aerial larvicidings, 2 rounds of catch basin larviciding, and 1,104 ground-based larvicidings have been accomplished thus far.

Most folks contaminated with West Nile virus haven’t any signs although some might develop fever together with headache, muscle aches, rash, and excessive fatigue. While most sufferers contaminated with West Nile virus illness go on to totally get well, some proceed to have well being issues months after an infection. In addition, about 1 in 150 folks, particularly these 55 years and older or with a weakened immune system, can develop a severe and doubtlessly deadly sickness of the mind and spinal twine known as West Nile neuroinvasive illness, resulting in modifications in psychological standing and muscle weak spot requiring hospitalization.

New Yorkers, particularly these at elevated danger for West Nile neuroinvasive illness, ought to use an EPA-approved mosquito repellent when outdoor to stop mosquito bites. People with sure medical circumstances or remedies that trigger extreme immunosuppression, reminiscent of chemotherapy and organ transplantation, are at higher danger of West Nile neuroinvasive illness and may contemplate avoiding going outdoor throughout nightfall and daybreak when mosquitoes that carry West Nile virus are energetic and chew. People with signs of West Nile virus ought to contact their well being care supplier.

West Nile virus was first detected in New York greater than 25 years in the past. From 2012 to 2021, a median of 16 folks per 12 months had been identified with West Nile neuroinvasive illness; from 2022 to 2024, the typical elevated to 31 folks per 12 months. Most New Yorkers identified with West Nile virus report that they didn’t use repellent or take different precautions to stop mosquito bites. New Yorkers ought to use repellent and provide it to their older neighbors and kinfolk.

New York City has greater than 40 species of mosquitoes, however West Nile virus is transmitted primarily by a number of Culex species, together with Culex pipiens, restuans, and salinarius.

Reducing Exposure to Mosquitoes

• Use an EPA-approved insect repellent containing picaridin, DEET, oil of lemon eucalyptus (not for kids underneath three), or merchandise that include the energetic ingredient IR3535. Visit the EPA site to go looking by product and length of effectiveness.
• Wear longs pants, lengthy sleeve shirts, and socks, along with utilizing repellent, particularly throughout daybreak and nightfall.
• People with severely compromised immune techniques ought to keep away from going outdoor throughout nightfall and daybreak when mosquitoes that carry West Nile virus are energetic and chew.
• Make certain home windows have screens. Repair or substitute screens which have tears or holes.
• Eliminate any standing water out of your property and eliminate containers that may accumulate water. Standing water is a violation of the New York City Health Code.
• Make certain roof gutters are clear and drained correctly.
• Clean and chlorinate swimming swimming pools and out of doors saunas and sizzling tubs. Keep them empty or lined if not in use. Drain water that collects in pool covers.

For extra details about West Nile virus or to report standing water, go to NYC Health: West Nile Virus or name 311.

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MEDIA CONTACT: Press Office PressOffice@well being.nyc.gov