West Nile virus, which is spread to humans through the bite of an infected mosquito, arrived unexpectedly in the United States in 1999. The virus is most transmittable in hot, humid, subtropical climates. Still, West Nile virus has continued to spread in the United States in the last 20 years and is now considered endemic.
Only 1 in 5 cases of West Nile virus result in a symptomatic illness and only 1 in 150 cases result in severe illness. Still, spread of the virus is of concern since there are currently no vaccines or medications to treat West Nile virus. West Nile virus is the leading cause of mosquito-borne disease in the continental United States.
In New York City, the New York City Department of Health and Mental Hygiene surveys local mosquito populations to determine where West Nile virus is present and in what quantity. In 2022, the department identified 1,137 mosquitoes that were positive for West Nile virus. This is a marked increase over the previous year, when 779 West Nile virus-positive mosquitoes were identified.
2 cases of West Nile virus infection have been reported in New York City this year. The Centers for Disease Control and Prevention reports that 54 cases have been reported nationwide and that 34% of these cases resulted in meningitis or encephalitis. Since the majority of West Nile virus cases are asymptomatic, there are likely more cases than have been reported.
Since mosquitoes breed in pools of standing water, New York City residents are being urged to curb the spread of mosquito-borne illness by eliminating areas of standing water. Health Commissioner Dr. Ashwin Vasan says that “we are in the height of West Nile virus season, but there are things you can do to decrease your risk of being bitten.”
Public health officials also recommend using insect repellent and wearing long sleeves and long pants during dusk and dawn when mosquitoes are most active.