Cases of chikungunya, a viral disease spread by mosquitoes in tropical climates, have been reported in Boston and surrounding communities among people returning from the Caribbean, state public health officials said Thursday.
The Boston Public Health Commission sent an alert to physicians Tuesday warning them to look out for symptoms of the illness, which causes severe fever and joint pain. Four cases have been reported just this week in Boston residents, and several cases have been confirmed elsewhere in New England during the past month.
The alert said patients who recently traveled to the Caribbean, including Haiti and the Dominican Republic, could be infected.
State health officials did not name the other communities that have seen cases, citing patient confidentiality.
Chikungunya is endemic to parts of Africa, Asia, southern Europe, and the Indian and Pacific Oceans, but began appearing in the Caribbean in December. The federal Centers for Disease Control began identifying cases in US travelers earlier this year, with 129 cases reported by July 1 across 27 states, Puerto Rico, and the Virgin Islands.
“We really wanted the health care providers to be aware that they should be advising some precautions for people,” said Dr. Anita Barry, director of the commission’s Infectious Disease Bureau. “We encourage people to avoid being bitten by mosquitoes, to use repellents, and if weather conditions are OK, to wear long sleeves and long pants.”
A public health alert was not issued because the type of mosquitoes that transmit chikungunya do not live here, and the virus cannot be transmitted person to person, said Dr. Catherine Brown, the state public health veterinarian.
These mosquitoes do live in many Southern states that have seen cases — such as Florida, which has 34 reported cases, the most of any state — elevating the risk that it will spread to local residents. So far, none of the reported cases in the United States has been locally transmitted.
“There’s nothing we need to do to prevent further spread in Massachusetts,” Brown said. “This is something that’s been on everybody’s radar screen since the end of last year. The fact that we are now beginning to identify people with infections of chikungunya who picked it up while they were traveling is not a surprise.”
Treatments for the disease do not exist. Instead, doctors can alleviate the fever, joint swelling, headaches, muscle pain, and rash that are often symptomatic of the virus. Deaths are rare, and it is usually cleared by the immune system in seven to 10 days.
“All you can do is make the patient comfortable with pain medications and bring the fever down,” said Dr. Jeffrey Gelfand, an infectious disease physician at Massachusetts General Hospital and professor at Harvard Medical School.
He added that many area doctors are unfamiliar with the disease. “Five years ago, if you had mentioned this virus, most infectious disease doctors would have never heard of it,” Gelfand said.
While chikungunya is not spread by mosquitoes in New England, West Nile virus and Eastern equine encephalitis are, and summer is when the risk is highest.
Public health officials are advising people to get rid of places mosquitoes can breed, such as buckets of water that have been sitting outside and kiddie pools.
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