First Locally Acquired Case of Chikungunya in New York State

The New York State Department of Health last week confirmed a case of locally acquired chikungunya in Nassau County on Long Island. This marks the first locally acquired case of chikungunya reported in New York State. No locally acquired cases have been reported in the U.S. states and territories since 2019.

An investigation suggests that the individual likely contracted the virus following a bite from an infected mosquito. While the case is classified as locally acquired based on current information, the precise source of exposure is not known.

The Aedes albopictus mosquito, known to transmit chikungunya, is present in parts of downstate New York. Local transmission can occur when a mosquito bites an infected traveler, becomes infected and bites another person. The disease cannot be spread directly from one person to another.

“Given the much colder nighttime temperatures, the current risk in New York is very low,” said State Health Commissioner Dr. James McDonald. “We urge everyone to take simple precautions to protect themselves and their families from mosquito bites.”

Chikungunya is a mosquito-borne disease most common in tropical and subtropical regions. Symptoms include fever and joint pain, headache, muscle pain, joint swelling, or rash. The illness is rarely fatal, and most patients recover within a week, though some may experience persistent joint pain. People at higher risk for severe disease include newborns infected around the time of birth, adults aged 65 and older, and individuals with chronic conditions such as high blood pressure, diabetes or heart disease.

In 2025, there have been three additional chikungunya cases outside New York City that were all linked to international travel to regions with active chikungunya infections. Routine mosquito testing conducted in New York has not detected chikungunya virus in any mosquito samples to date.