West Nile virus symptoms explained as NYC reports new case
New York City health officials have reported the city’s first human case of West Nile virus (WNV) of 2026, renewing warnings for residents to protect themselves from mosquito bites during the peak summer season.
According to the New York City Department of Health, the individual contracted the virus after spending time outdoors in New York City and several locations outside the city.
Mosquitoes carrying West Nile virus have been detected in all five boroughs since June, and the virus has been found in more than 1,000 mosquito pools citywide this year.
What Is West Nile Virus?
West Nile virus is a mosquito-borne disease that spreads to humans through the bite of an infected mosquito. It can’t be spread from person to person. The virus is the leading cause of mosquito-borne disease in the continental United States and typically circulates during the warmer months, when mosquito populations are most active.
In New York City, mosquitoes carrying West Nile virus are present every year from June through to October, with activity generally peaking in August and September.
Which States Have Reported West Nile Cases?
According to the Centers for Disease Control and Prevention (CDC), there have been 222 human cases of West Nile virus reported nationwide in 2026 across 32 states—now 33 with the recent case in New York—with the majority in Arizona, Texas, and California.
Symptoms of The West Nile Virus
Most people infected with West Nile virus experience no symptoms at all. However, some people develop a mild illness that can include:
- Fever
- Headache
- Muscle aches
- Fatigue
- Skin rash
These symptoms can last for days or weeks and may resemble those of other viral infections.
From 2012 through to 2021, an average of 16 New Yorkers were diagnosed each year with West Nile neuroinvasive disease. Between 2022 and 2025, that average rose to 31 cases annually.
Health officials warn that a small percentage of people develop a much more serious form of the disease known as West Nile neuroinvasive disease, a severe condition that affects the brain and spinal cord.
The CDC reports that 156 neuroinvasive cases have been reported in the United States so far in 2026, and, according to the NYC Health Department, about one in 150 people infected with West Nile virus develops this potentially life-threatening illness, which can cause changes in mental status and muscle weakness requiring hospitalization.
In some cases, the disease can be fatal. While many patients make a full recovery, some experience long-term health complications or permanent disability.
Who Is Most at Risk?
Older adults and people with weakened immune systems face the highest risk of severe illness.
The Health Department said people aged 65 and older are three times more likely to develop neurologic disease from West Nile virus than younger people. Individuals with chronic medical conditions such as cancer, diabetes, hypertension and kidney disease are also at increased risk.
What Should You Do If You Have Symptoms?
The NYC Health Department advises anyone experiencing symptoms consistent with West Nile virus to contact a healthcare provider.
People who develop serious symptoms, particularly confusion, severe weakness, or other neurological issues, should seek medical attention immediately. Early evaluation can help doctors rule out other illnesses and provide supportive treatment if needed.
How Can You Protect Yourself?
Because there is no specific treatment or vaccine for West Nile virus in the general public, prevention remains the best defense.
- Using EPA-registered insect repellents containing DEET, picaridin, IR3535 or oil of lemon eucalyptus.
- Wearing long-sleeved shirts, long pants, socks and shoes when outdoors.
- Limiting outdoor activity around dawn and dusk, when mosquitoes that spread the virus are most active.
- Installing and repairing window and door screens.
- Eliminating standing water from buckets, flowerpots, birdbaths, gutters and other containers where mosquitoes can breed.
- Maintaining swimming pools, hot tubs and ornamental ponds to prevent mosquito reproduction.
“West Nile virus is spread by mosquito bites and cannot spread from person to person. The good news is it’s preventable,” NYC Health Commissioner Dr. Alister F. Martin said in a statement urging residents to take precautions during mosquito season.
The city’s latest case serves as a reminder that while most infections are mild or symptom-free, the virus can cause severe illness in vulnerable individuals, making mosquito-bite prevention especially important as summer draws to a close.
Newsweek has reached out to the New York Department of Health via email for comment.
Contact Newsweek editor on this story: Edward Pearcey.
