A U.S. travel health notice advises those traveling to St. Martin in the Caribbean to take steps to protect themselves from mosquito bites, officials say. Officials at the Centers for Disease Control and Prevention said they are closely following new reports of the mosquito-borne chikungunya virus among residents of the French side of St. Martin. While outbreaks of chikungunya have been reported in some parts of Africa, Europe, Asia and the Pacific, this marks the first time the disease has been reported among non-travelers in the Western Hemisphere. The World Health Organization reported 10 confirmed cases on the island. Testing to confirm other suspected cases is ongoing. Chikungunya virus is transmitted by the same mosquitoes that spread dengue virus. These mosquitoes are widely found in the Caribbean and the tropics. The affected St. Martin residents had not traveled recently, suggesting that chikungunya virus is now present in island populations of mosquitoes and is being spread locally. Further spread on St. Martin, to other Caribbean islands, and to the surrounding mainland areas is possible in the coming months and years, the CDC says. The mosquitoes that spread it are also found in some areas of the United States, officials said. "Microbes know no boundaries, and the appearance of chikungunya virus in the Western hemisphere represents another threat to health security," Dr. Tom Frieden, director of the CDC, said in a statement. "CDC experts have predicted and prepared for its arrival for several years and there are surveillance systems in place to help us track it." Travelers should take steps to protect against mosquito bites including: using insect repellent, wearing long sleeves and pants and using air conditioning and screens on windows and doors to keep mosquitoes out. Travelers returning from the Caribbean who experience fever and joint pains as well as other symptoms of chikungunya such as headache, muscle pains, or rash should seek medical care, and healthcare providers should be on the alert for possible cases, the CDC said.