Unusual mosquito-borne chikungunya virus case reported in US

A mosquito lands on a person's leg on Tuesday, Aug 6, 2024, in East Lansing, Michigan. Mosquitoes carry a host of illnesses, including chikungunya, found in a Long Island, New York, resident on October 2025.

A resident of New York has contracted the state's first known case of the mosquito-borne chikungunya disease acquired locally, officials said.

The person infected in Long Island likely got the virus after being bitten by an infected mosquito, the New York State Department of Health said in a statement. The case was confirmed through testing at the department's Wadsworth Center.

More details about the infected person's illness and symptoms were not shared by the department, but common symptoms can include fever and joint pain. It's rare for chikungunya to kill somebody, but its symptoms can be severe and debilitating, according to the health department.

The case in Nassau County marks the first time someone is believed to have contracted the virus locally; cases are typically diagnosed in people who have travelled to Africa, Asia, the Caribbean or Latin America. Local transmission can happen when a mosquito bites an infected recent traveler, becomes infected, and then bites a healthy person and passes the virus onto them. Humans can't spread it to each other, except in extreme cases such as blood transfusions or handling infected blood.

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

What are symptoms of chikungunya?

Symptoms include fever, joint pain, headache, muscle pain, joint swelling and rash, according to the Centers for Disease Control and Prevention.

Symptoms usually appear between three to seven days after being bitten by an infected mosquito. The most at-risk for severe illness are babies, people over 65 and people with certain medical conditions. Most people recover in about a week, but joint pain can be severe, persistent and disabling in some cases, according to the CDC.

There is no specific treatment for chikungunya, though there is a vaccine available to travelers to help prevent the disease.

First case of locally transmitted virus in New York

The infected person in New York is the first to acquire chikungunya locally in the state. The United States hasn't seen a locally acquired infection since 2019, according to authorities. There have been 88 travel-associated cases of chikungunya in the United States so far this year.

Cases have widely fluctuated in the country over the past decade, with low levels seen in 2020 and 2021 as travel declined at the start of the COVID-19 pandemic. In 2024, there were 199 total cases, all associated with travel. In 2023, there were 152.

In the summer, the World Health Organization issued an urgent call for action to prevent a chikungunya epidemic like one that went worldwide from 2004 to 2005. In 2025, summer saw a new surge in cases with major outbreaks in the Indian Ocean islands hit hard in the last epidemic.

There is a current travel health notice for chikungunya in Bangladesh; Cuba; Guangdong Province, China; Kenya; Madagascar; Somalia; and Sri Lanka, according to the CDC. Countries with an elevated risk to American travelers include Brazil, Colombia, India, Mexico, Nigeria, Pakistan, the Philippines and Thailand.

How to avoid chikungunya, other mosquito-borne illnesses

Here's how the New York State Department of Health recommends you protect yourself from catching chikungunya, which can also help prevent other mosquito-borne viruses: