Editor's note: This was updated July 17, 2014.
June 17, 2014 -- A crippling mosquito-borne virus with a tongue-twisting name -- chikungunya -- has spread to the Caribbean, and U.S. travelers have brought it home to more than half the states in the U.S.
Here's what you should know about this virus and how to lower your risk of infection, especially if you're traveling to the Caribbean. While the virus remains rare in the U.S., no vaccine is available.
What is chikungunya virus?
The virus is mainly “spread from person to person through mosquitoes," says Kristy Murray, DVM, PhD, an infectious disease specialist in Houston.
It's pronounced "chik-en-gun-ye."
''It's an African word, and it translates to 'that which bends up,'" Murray says, because people bend up with joint pain, one of the most common symptoms.
Where did it come from, and how does it spread?
Scientists believe the virus originated in 1952 in southern Tanzania. Chimpanzees or other animals were probably first infected, says Amesh Adalja, MD, an infectious disease specialist in Pittsburgh.
Mosquitoes that bit these animals became infected, then bit and infected people.
The virus can stay in a person's system for about a week, according to the World Health Organization.
When a mosquito feeds on an infected person, the mosquito can become infected and can bite and infect others.
The Aedes aegypti and Aedes albopictus mosquitoes transmit chikungunya. They also transmit dengue fever, another disease caused by a virus.
Where has chikungunya been found?
In the past decades, outbreaks have occurred in Africa, Asia, Europe, and the Indian and Pacific Oceans.
The virus was found for the first time in the Americas on Caribbean islands in late 2013. More than 20 Caribbean and South American countries and territories have reported outbreaks, according to the CDC.
As of July 17, 243 travel-associated cases, in people returning from the Caribbean or Asia, have been reported in 31 states and the U.S. Virgin Islands, according to the CDC.
On July 17, the CDC reported the first locally transmitted case of chikungunya in Florida, in a male who hadn't traveled outside the U.S.
“CDC officials believe chikungunya will behave like dengue virus in the United States, where imported cases have resulted in sporadic local transmission but have not caused widespread outbreaks,” the agency said in a statement.
Puerto Rico has 121 locally transmitted cases, and the U.S. Virgin Islands have two.
What are the symptoms?
"Usually fever, rash, muscle aches, and joint pain," Adalja says.
"When a person first becomes sick, they will think they have a flu-like illness," Murray says.
Symptoms first appear about 4 to 7 days after the bite, according to the World Health Organization.
A high percentage of those infected become sick, Murray says. She estimates that 90% of those bitten will develop symptoms.
What is the treatment?
How severe is it?
The disease is rarely fatal, according to the World Health Organization, although in older people, the disease can contribute to the cause of death.
As of July 11, 5,037 cases have been confirmed in the Caribbean with 21 deaths, according to the Pan American Health Organization.
"Most people will get better in about a week," Adalja says, although some will need to be hospitalized. A small number of people will have joint pain that lasts for months, he says.
How do you minimize risk?
Travelers to areas where the virus is circulating can take precautions against mosquito bites. The mosquitoes carrying the virus can bite day or night, indoors or out. The CDC advises:
- Cover up exposed skin by wearing long-sleeve shirts, long pants, and hats.
- Use insect repellent that contains as an active ingredient DEET, picaridin, oil of lemon eucalyptus, PMD, or IR3535.
- Consider treating clothing and gear such as boots and tents with the repellent permethrin.
- Stay and sleep in rooms with screens or air conditioning.
- Use bed nets if you are sleeping outdoors.