Mosquitoes spreading chikungunya virus brought home by US travellers
Florida witnesses first cases of locally acquired chikungunya infection
Health officials are saying that for the first time, US mosquitoes are spreading a virus that has been tearing through the Caribbean.
Two people in Florida have domestically acquired chikungunya infections, officials said on Thursday.
In both cases, 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.
Federal officials said it was 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 US.
"The arrival of chikungunya virus, first in the tropical Americas and now in the US, underscores the risks posed by this and other exotic pathogens," said Roger Nasci, of the Centres for Disease Control and Prevention (CDC), in a statement.
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, an official with the Department of Health.
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 and no specific treatment.
This virus is not spread person to person, but rather by the bite of certain mosquitoes. That is why health officials believe the virus is spreading in the US - the two cases had not recently left the country.
The infected Floridians were described as a 41-year-old woman who began experiencing symptoms on June 10, and a 50-year-old man who first noticed symptoms July 1. Philip said both were doing well.
More than 230 chikungunya cases had been reported in Americans this year, but all the others were travellers believed to have been infected elsewhere.
Now that chikungunya is in the US, CDC officials think it will behave like dengue virus, with imported cases causing occasional local transmissions but not widespread outbreaks.
Chikungunya was first identified in 1952 in Tanzania. It first appeared in the Americas late last year on a Caribbean island. By July 11, more than 355,000 suspected and confirmed cases were being reported in the Americas.
Officials have been expecting it to land in the United States, noting that two types of mosquitoes that can carry the virus live there.
Earlier this week, the
New England Journal of Medicine published an editorial on the looming chikungunya threat by two National institutes of Health infectious diseases experts - Dr David Morens and Dr Anthony Fauci.
They said several chikungunya vaccines were being developed. But even if they proved effective, they would be years away from becoming available.
Mosquito control and avoidance were the best current options, they said.