First locally acquired chikungunya virus case confirmed in US since 2019

Health officials in New York confirmed a person tested positive for the mosquito-borne chikungunya virus in what is the first locally acquired case in the United States since 2019. 

The transmission detected in a Nassau County resident comes after the Centers for Disease Control and Prevention (CDC) warned Americans to be on high alert for the virus following outbreaks in Cuba and China this year. 

“A communicable disease investigation conducted by Nassau County Department of Health (NCDOH) found that the individual began experiencing symptoms in August. The investigation revealed that the individual had history of travel outside of Nassau County during the period of inoculation, but did not report traveling abroad,” the Nassau County Department of Health said Tuesday. 

“No Chikungunya Virus has been detected in local mosquito pools to date, and the risk to the general public continues to remain low,” it added. 

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The CDC said most people infected with the chikungunya virus develop some symptoms, which usually begin around three to seven days after a bite by an infected mosquito. 

“The most common symptoms are fever and joint pain. Other symptoms may include headache, muscle pain, joint swelling, or rash. Most people get better within a week; however, some can have severe joint pain for months to years following acute illness,” according to the CDC. 

“People at risk for more severe disease include newborns infected around the time of birth, older adults (65 years or older), and people with medical conditions such as diabetes or heart disease. Death from chikungunya is rare,” the CDC added. “There is no specific treatment for chikungunya.” 

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The CDC said on its website that, “Locally acquired chikungunya cases have not been reported from U.S. states or territories since 2019.” 

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

“Mosquito bites are more than just a nuisance, they can sometimes spread illnesses that affect both people and animals,” said Nassau County Commissioner of Health Irina Gelman. “While the 2025 mosquito season is essentially over with cooler weather in Nassau County, this case serves as a reminder to take precautions against mosquito bites during the season and when traveling to areas where mosquito-borne illnesses are present.” 

“Our Wadsworth Center has confirmed this test result, which is the first known case of locally acquired Chikungunya in New York State. Given the much colder nighttime temperatures, the current risk in New York is very low,” added State Health Commissioner James McDonald.