West Nile Virus Detected in NYC's Boroughs

The mosquito-transmitted West Nile virus was first detected in New York's five boroughs more than 25 years ago, with about 31 people infected in recent years. 

According to the New York Health Department press release on August 22, 2025, West Nile virus disease has been reported in two New Yorkers, both residents of Queens.

One individual was diagnosed with West Nile fever, was briefly hospitalized, and has since been discharged.

The second individual was diagnosed with West Nile neuroinvasive disease and is currently hospitalized with encephalitis, an infection in the brain.

In addition, the virus was detected in blood donations from two individuals, one a resident of Brooklyn, the other of Staten Island.

Recent reports of two more individuals (both from Brooklyn) with possible West Nile virus disease are under investigation.

While most patients infected with West Nile virus disease go on to fully recover, some continue to have health problems months after infection. In addition, about 1 in 150 people, especially those 55 years and older or with a weakened immune system, 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, according to the Health Department.

"West Nile virus can cause serious illness, especially among people over 55 and with weakened immune systems," said Acting Health Commissioner Dr. Michelle Morse in the press release.

"The Health Department says ... 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."

And, "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 stated ten adulticiding spray operations, three aerial larvicidings, two rounds of catch basin larviciding, and 1,104 ground-based larvicidings have been completed to date.

Across the United States, the U.S. CDC reports that 33 states have confirmed over 320 WNV cases in 2025.

And in Europe, as of August 20, 2025, nine countries have reported human cases of WNV: Albania, Bulgaria, France, Greece, Hungary, Italy, Romania, Serbia, and Spain.

From a prevention perspective, there are no West Nile virus vaccines available in 2025.