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Mosquito-Borne Chikungunya Virus Hits U.S.
The first locally acquired case of chikungunya, a mosquito-borne disease, has been reported in Florida, according to a health alert from the Centers for Disease Control and Prevention (CDC).
Although the agency does not expect widespread cases of chikungunya in the U.S. this summer, American travelers infected overseas may continue to return and bring the virus with them.
Chikungunya virus is transmitted to people by two species of mosquitoes, Aedes aegypti and Aedes albopictus. Both species are found in the southeastern U.S. and in limited parts of the Southwest; Aedes albopictus is also found further north — up the East Coast and through the Mid-Atlantic States — and in the lower Midwest.
People infected with the chikungunya virus typically develop fever and joint pain. Other symptoms can include muscle aches, headaches, joint swelling, or rash. The virus is not spread person to person. There is no vaccine and no specific treatment for infection.
The best way for individuals to protect themselves from chikungunya is to prevent being bitten by mosquitoes by using insect repellent, by wearing long sleeves and pants, by using air conditioning or window/door screens to keep mosquitoes outside, and by reducing mosquito breeding grounds, such as standing water.
The CDC is currently working with the Florida Department of Health to assess whether there are additional locally acquired cases and is providing consultation on ways to prevent further spread of the virus by controlling mosquitoes and by educating people about personal and household protection measures to avoid mosquito bites.
Chikungunya is not a nationally notifiable disease in the U.S. However, chikungunya cases can be reported to ArboNET, the national surveillance system for arthropod-borne diseases.
From 2006 to 2013, studies identified an average of 28 people per year in the U.S. with positive tests for recent chikungunya virus infection (range: five to 65 per year). All were travelers visiting or returning to the U.S. from affected areas, mostly in Asia. Only a quarter of the cases were reported to ArboNET.
Beginning in 2014, cases have been identified in travelers returning from the Caribbean. As of July 15, a total of 357 chikungunya cases were reported to ArboNET from U.S. states and territories. A total of 123 locally transmitted cases have been reported from Puerto Rico and the U.S. Virgin Islands. All other cases occurred in travelers returning from affected areas in the Caribbean, South America, the Pacific Islands, or Asia.
The newly reported case in Florida represents the first time that mosquitoes in the continental U.S. are thought to have spread the virus to a non-traveler.