Photograph USDA Via Associated Press

Read Caption

Aedes aegypti mosquitoes, like the one above, are a common carrier of chikungunya.

Photograph USDA Via Associated Press

First U.S. Chikungunya Virus Infections Take Hold

The mosquito-borne disease has established a U.S. foothold in Florida.

Two people in South Florida are the first to contract a debilitating mosquito-borne disease called chikungunya within the continental United States.

The disease, which causes severe joint pain but is rarely lethal, has spread rapidly throughout the Caribbean in recent months. Of the previous 234 cases reported in the continental U.S., all were in people who got mosquito bites while traveling. (Related: "Mosquitoes Carry Painful Chikungunya Disease to Americas.")

The two people, a 41-year-old woman in Miami and a 50-year-old man in Palm Beach County, had not traveled before getting sick, according to the Florida Department of Health.

African Import

Chikungunya (pronounced chick-un-GOON-ya) has infected more than 350,000 people across the Caribbean since it first arrived there from Asia in December, and killed 21 people in the region. It is also endemic in Africa and islands in the Indian Ocean and western Pacific.

Chikungunya typically sweeps across a population through mosquito bites and then dies back after most people have been infected. It cannot be passed person to person, and researchers believe that people can be infected only once.

The disease causes fever and searing joint pain that usually resolves in about a week. Some people, though, continue to have pain for months or years. Muscle aches, headaches, joint swelling, or rash can also accompany the disease. There is no vaccine and no treatment other than addressing symptoms with agents to reduce fever and pain.

Emerging Infection

Chikungunya, first identified in the early 1950s in Tanzania, is carried by the same mosquitoes that carry the dengue virus. Another species believed to be able to carry the disease lives in large numbers in the United States, as far north as Chicago.

The best way to prevent infection, health officials say, is to avoid getting bitten by mosquitoes and to block the insects from breeding by eliminating nearby sources of standing water.

Follow Karen Weintraub on Twitter.