Mosquito-Borne Illness Rarely Seen in U.S. Is Suspected on Long Island

Health officials said they were investigating whether the debilitating mosquito-borne virus chikungunya was circulating in New York after a woman tested positive on Long Island in a preliminary screening.

Although the virus has exacted a steep toll across parts of South America, Africa and Asia during the past 20 years, the United States has seen scant local transmission. The last time the disease was known to have been transmitted locally in the United States was about a decade ago, when fewer than 15 cases were detected in Florida and Texas.

But a 60-year-old woman in the Town of Hempstead, a hamlet in central Nassau County that is about 20 miles east of Manhattan, said she had tested positive for the virus in a preliminary screening test this month. Her blood samples have been sent to the state Health Department’s public health laboratory in Albany to confirm a diagnosis, a Nassau County official said.

“The New York State Department of Health is investigating a possible locally acquired case of chikungunya virus,” a department spokeswoman, Danielle De Souza, said in a statement. “No locally acquired cases have ever been reported in New York State, and the risk to the public remains very low.”

In an interview, the woman, who spoke on the condition of anonymity to describe a sensitive health matter, said she had not traveled anywhere recently and had been shocked when she saw the test results. She said she wanted to share her experience out of concern that the virus was circulating undetected and that others might be falling ill, too. She worried that doctors were not even considering chikungunya as a possible diagnosis.

She said that she fell ill a month ago, on Aug. 21, and was stricken with severe joint pain, the classic symptom of chikungunya. Pain racked her feet, ankles, knees, wrists, hands and shoulders, especially her right shoulder. It felt like it was on fire, almost as though it were being pulled apart, she said.

Chikungunya is known for causing debilitating joint pain, which can clear up quickly or linger for months or even years, contributing to a surge in new disabilities in countries that see outbreaks.

If the woman is confirmed to have chikungunya, it would signify the arrival of a new public health threat from arthropods in the New York region. Ticks already present a serious health peril on Long Island, where their bites sicken thousands of people each year. Suffolk County, which includes the eastern two-thirds of the island, has more Lyme disease cases some years than any other county in the United States.

Long Island has also been a hot spot for alpha-gal syndrome, a meat allergy linked to tick bites, including those from the lone star tick. That type of tick arrived on Long Island about 50 years ago and is the dominant tick in parts of Suffolk County. More than 3,700 cases of alpha-gal syndrome were detected in the county between 2017 and 2022, according to the U.S. Centers for Disease Control and Prevention.

Chikungunya has surged globally as climate change expands the range of the mosquitoes that carry it. China has faced a major outbreak this year, and the disease has been circulating in France and Italy, too. It is now endemic across much of the Caribbean and South and Central America.

The disease was first identified in Tanzania in the early 1950s. Its name comes from the Kimakonde language spoken there and means “that which bends up.” The virus would periodically cause waves of illness. India experienced a massive outbreak between 2005 and 2007.

The disease established itself in the Western Hemisphere starting in late 2013, when it was detected on St. Martin. It tore though the Caribbean, sickening hundreds of thousands of people in that first year alone. New Yorkers returning from trips sometimes brought the virus back home with them, but there were few signs of any local transmission.

New York was once viewed as relatively insulated from chikungunya, partly because the mosquito that seemed to be the main vector, the Aedes aegypti, or yellow fever mosquito, is not naturally found there. Increasingly, another mosquito, Aedes albopictus, commonly known as the Asian tiger mosquito, is driving chikungunya outbreaks. That mosquito is a relative newcomer to the United States, but its range now extends to parts of New York.

The Nassau County woman said that her recent illness caused joint pain in her shoulder so severe that she struggled to sleep or do much of anything at all. Though the fiery pain has abated somewhat, she still has difficulty walking because of pain in the ball of her foot.

Dr. Bruce Farber, an infectious disease expert at Northwell Health, the state’s largest hospital system, said that if chikungunya had arrived in New York, an infected mosquito might have hitched a ride on a plane.

“Mosquitoes are sometimes carried back in luggage or in airplanes,” he said.

“That’s the most likely way,” he said, noting that malaria sometimes spreads in a limited fashion through the same means, a phenomenon called “airport malaria.”