1. Carter, David


Concerns expressed that the disease may become endemic to the mainland.


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It is now clear that the chikungunya virus is infecting travelers from the U.S. mainland to the Caribbean. A mosquito-borne disease, chikungunya infection resembles infection with the dengue virus. The most common symptoms are fever and joint pain; patients may also experience headache, muscle pain, joint swelling, and rash. Symptoms usually begin three to seven days after a bite by an infected mosquito and can be severe and disabling, sometimes lasting for months. Newborns infected near the time of birth, the elderly, and people with certain medical conditions (such as hypertension, diabetes, or heart disease) are at risk for more severe disease.

Figure. Colored tran... - Click to enlarge in new windowFigure. Colored transmission electron micrograph of chikungunya virus particles (yellow). Photo by O. Schwartz, M. Sourisseau, Mc. Prevost / Institute Pasteur / Science Photo Library.

On June 13 the Rhode Island Department of Health reported two cases of infection with the virus involving travelers who had returned from the Dominican Republic. Six days later the Tennessee Department of Health confirmed that two residents of that state were infected with the virus after travel to the Caribbean. As of July 15, the Centers for Disease Control and Prevention (CDC) had documented 234 cases of chikungunya in the United States and its territories, although no transmission has been identified in the continental United States itself. However, in Puerto Rico and the U.S. Virgin Islands, 199 and two cases, respectively, appear to have been the result of local transmission. (See for the most current statistics.)


The CDC first reported the presence of the virus, which originated in Africa, in the Western Hemisphere in December 2013. Health officials are worried that the virus will eventually become endemic to the U.S. mainland, as the West Nile virus has done.


The CDC recommends that travelers to the Caribbean protect themselves from mosquito bites and that travelers in high-risk groups discuss their travel plans with their health care providers. In addition to the patients at high risk for severe disease listed above, those at elevated risk for contracting chikungunya include people with arthritis; women in late pregnancy; long-term travelers; and people who might have difficulty avoiding mosquito bites, such as those planning to spend a lot of time outdoors or staying in rooms without window screens or air conditioning.


CDC travel advisories related to chikungunya are available at Although health care professionals aren't required to report chikungunya disease, reporting cases to local or state departments of health can assist in tracking the disease's spread.-David Carter