What is Chikungunya?

What you need to know about the mosquito-borne illness following reports of a locally acquired U.S. case

Rachel Nania,

Updated October 21, 2025

AARP

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En español

Published May 14, 2025

/ Updated October 21, 2025

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A person in Long Island, New York, has tested positive for chikungunya, a mosquito-borne illness that is usually associated with international travel. Officials say the infection occurred within the state, marking the first locally acquired case in New York and the first in the U.S. since 2019.

According to the New York State Department of Health, the individual likely contracted the virus — which can cause fever and severe joint pain — from a bite of an infected mosquito. Mosquitoes become infected after feeding on someone who already has the virus, the U.S. Centers for Disease Control and Prevention (CDC) explains. The virus is not spread from person to person.

State health officials say the species known to transmit chikungunya, the Aedes albopictus mosquito, is present in parts of New York. However, “given the much colder nighttime temperatures, the current risk in New York is very low,” State Health Commissioner Dr. James McDonald said.

Still, the new case has prompted questions about the virus and its presence in the U.S. Here’s what you need to know about chikungunya and how to best protect yourself from the mosquito-borne illness.

What is chikungunya?

Chikungunya is a disease caused by the chikungunya virus, which is spread by infected mosquitoes, according to the World Health Organization (WHO). The virus can be found in many parts of the world but tends to circulate in tropical and subtropical regions.

WHO officials say chikungunya outbreaks have become more frequent and widespread in recent years. About 200 cases of chikungunya were reported in the U.S. in 2024; all of them were travel-associated.

What are the symptoms of chikungunya?

The most common symptoms of chikungunya are fever and joint pain, which can be severe and long-lasting. In fact, the name chikungunya means “that which bends up,” to describe “the contorted posture of infected people with severe joint pain,” the WHO explains.

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Other symptoms of the disease can include headache, muscle pain, joint swelling and rash, and these warning signs typically develop three to seven days after an infected mosquito bites you.

Older adults are at higher risk for more severe disease from an infection, the CDC says; so are newborns and people with certain medical conditions such as high blood pressure, heart disease and diabetes.

A blood test can diagnose the infection. However, according to the CDC, there are currently no medicines to treat chikungunya. Rest, fluids and over-the-counter pain relievers are often recommended to help with symptoms.

How can you prevent chikungunya?

Because chikungunya is a mosquito-borne virus, “using insect repellent and wearing long sleeves and long trousers really helps prevent infection,” says Dr. William Schaffner, an infectious disease expert and professor of preventive medicine at Vanderbilt University School of Medicine.

There’s also a vaccine that is recommended for some international travelers.

Who should get the chikungunya vaccine?

According to the CDC, the chikungunya vaccine is recommended for some adults traveling to a country or territory where there is a current chikungunya outbreak. People staying for several months in a country where chikungunya has spread should also consider the vaccine.

Only one vaccine option is currently available in the U.S., following the recent suspension of a live-attenuated vaccine called Ixchiq. Use of the vaccine was previously on pause after several countries reported serious adverse events in older individuals who had received it.

The underlying cause of the adverse events isn’t fully understood, Schaffner told AARP when the vaccine was first paused. “But it is known that chikungunya itself disproportionately causes serious illness in older persons, and this vaccine, Ixchiq, is a live attenuated vaccine,” meaning it contains a weakened version of the virus.

Officials at the Food and Drug Administration (FDA) say the vaccine may cause symptoms that are similar to symptoms experienced by people with chikungunya disease. “The going thought is that somehow this tamed virus is not tamed enough for use in older persons,” Schaffner explained.

There is another chikungunya vaccine available in the U.S., called Vimkunya, that does not use a live or weakened form of the chikungunya virus.

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