WEST PALM BEACH, Fla. — Health officials are reporting the first domestically-acquired infections in the United States of a mosquito-borne virus that has spread rapidly through the Caribbean.

Florida health officials said there have been two domestically-acquired chikungunya infections. In both, they said, a person infected with the virus after visiting the Caribbean was then bitten again by an uninfected mosquito in Florida, which then transmitted the illness further.

Health officials urged residents to prevent mosquito bites, but said there was no cause for alarm.

“There is no broad risk to the health of the general public,” said Dr. Celeste Philip, a public health official with the Department of Health.

Federal officials noted it’s an unfortunate milestone in the spread of a painful infectious disease that has raced across the Caribbean this year and is apparently now taking root in the United States.

“The arrival of chikungunya virus, first in the tropical Americas and now in the United States, underscores the risks posed by this and other exotic pathogens,” said Roger Nasci of the Centers for Disease Control and Prevention, in a prepared statement.

Chikungunya virus is rarely fatal. Infected people typically suffer fever, severe joint pain and swelling, muscle aches, headaches or rash. Patients usually recover in about a week, although some people suffer long-term joint pain. There is no vaccine.

This virus is not spread person to person, but rather by the bite of certain mosquitoes. That’s why health officials believe the virus is spreading here – the two cases had not recently left the country.

The infected Floridians were described as a 41-year-old woman in Miami-Dade County who began experiencing symptoms on June 10, and a 50-year-old man in Palm Beach County, who noticed symptoms July 1.

Philip said both are doing well.