The New York City Health Department has confirmed the city's first human case of West Nile virus this year in a resident who spent time outdoors. The health department announced on Wednesday that the resident contracted the infection after spending time in areas both around and outside the city.
City health officials released no further details regarding the individual's identity or how they became ill. Mosquitoes carrying West Nile virus are present across New York City every year from June through October, with peak transmission occurring between August and September.
The city has intensified its mosquito surveillance and expanded vector control efforts after detecting the virus in mosquito samples across all five boroughs since June. Health authorities noted that the virus has been detected in twice as many mosquito samples as were found during the same period last summer.
Alister Martin, the New York City health commissioner, urged residents to take protective measures during the height of the season. "The good news is it's preventable," Dr. Martin said in a statement. "With mosquito season in full swing, we’re encouraging New Yorkers to take extra precautions to minimize the risk of mosquito bites." He added that the best steps "to protect yourself are simple: wear insect repellent, cover up during dawn and dusk, and get rid of standing water around your home."
Nationwide spread and state transmission rates
The New York case comes amidst a broader rise in infections across the United States. Data from the Centers for Disease Control and Prevention as of August 18 shows 222 human cases of West Nile virus reported so far this year across 32 states, though CDC data typically lags behind local health department reporting. Arizona has recorded the highest number of cases with 76, followed by Texas with 31 and California with 29.
West Nile virus is a mosquito-borne flavivirus primarily transmitted to humans through the bite of infected Culex mosquitoes. The infection is most common in Great Plains states such as North Dakota, South Dakota, Nebraska and Colorado. Major urban centers including Los Angeles, Chicago and Dallas-Fort Worth also record high infection levels due to large human populations.
Mosquito season in the United States typically runs from late spring through early fall. However, many states have seen extended mosquito seasons in recent years due to increases in mosquito prevalence later in the calendar year.
Symptoms, severe illness and long-term risk
Most people infected with West Nile virus experience few or no symptoms. According to health officials, about one in five infected individuals develops symptoms such as fever, headaches, nausea, diarrhea, joint pain and pain behind the eyes.
About one in 150 cases develops severe neuroinvasive disease, in which the virus penetrates the blood-brain barrier and infects the meninges, leading to meningitis and potential paralysis. Neuroinvasive illness proves fatal in about one out of 10 people who develop nervous system infections, representing approximately one in 1,500 total West Nile cases.
Older adults, individuals with weakened immune systems and those living with chronic medical conditions face the highest risk of developing severe illness. Survivors of neuroinvasive West Nile disease may suffer long-lasting complications, including memory problems, chronic fatigue, muscle tremors and permanent neurological damage.
Historical trends and CDC prevention advice
So far in 2026, no deaths from West Nile virus have been recorded nationwide, with 156 of the 222 reported human cases classified as neuroinvasive. Last year, the United States recorded 2,100 total human cases, up from 1,800 cases the previous year, resulting in 172 deaths and 1,342 hospitalizations for neuroinvasive disease. New York City reported 18 human cases of West Nile virus last year, while New York State recorded a total of 59 cases.
Health authorities emphasize that West Nile virus is primarily prevented by avoiding mosquito bites. CDC officials recommend using insect repellents containing DEET, wearing long-sleeved shirts and long pants when outdoors, and remaining indoors between dusk and dawn during the summer months.
