Health officials in Puerto Rico on Thursday declared an epidemic of the mosquito-borne virus known as chikungunya.
Health Secretary Ana Rius said more than 200 cases have been confirmed on the island as of June 25, and that the majority of them have been reported in the capital of San Juan and nearby areas.
The first case of chikungunya in the U.S. territory was reported in late May.
Also on Thursday, officials in Jamaica reported the island's first confirmed case. Chief medical officer Dr. Kevin Harvey said the virus was found in a person who had recently traveled to a country where there have been locally transmitted cases.
Across the Caribbean, the Pan American Health Organization has recorded more than 354,000 suspected and confirmed cases as of July 11. The Western Hemisphere's first locally transmitted case was confirmed in December in the French Caribbean territory of St. Martin.
Chikungunya was first identified in Africa in 1953. It causes a high fever and severe pain in the joints, but is rarely fatal. There is no vaccine, and it mainly is treated with pain medication.
Explore further: US Virgin Islands confirms first chikungunya case (Update)