A mosquito-borne virus that can cause debilitating joint pain lasting for years has spread to the continental U.S. after infecting hundreds of thousands of people in the Caribbean and Central America.
The virus is called Chikungunya, an African name meaning “to become contorted.” While the illness, first identified in Tanzania in 1952, has long bedeviled Africa and Asia, the only recorded cases in the U.S. before July involved patients who contracted the virus abroad.
Now, 11 cases have been confirmed as originating in Florida, spurring concern this may be the beginning of the type of explosive growth seen elsewhere from a disease that has no vaccine or cure. Medical and environmental experts are debating how best to quell the outbreak before it takes off.
“In a way it’s surprising it hasn’t been here yet,” said Scott Weaver, a professor at the University of Texas Medical Branch at Galveston.
Patients who contract Chikungunya have joint swelling and pain, fever, headache and rash for about a week, though some symptoms last months or years in some patients, according to the U.S. Centers for Disease Control and Prevention.
While the disease generally isn’t fatal, more than 100 people have died in the Western Hemisphere since December, according to the Pan American Health Organization. Treatment includes hydration, rest and medicine that reduces fever or pain such ibuprofen or acetaminophen.
Now that Chikungunya is in Florida, it could infect 10,000 people in that state alone, according to Walter Tabachnick, the director of the Florida Medical Entymology Laboratory, who said his estimate is based on the exponential growth of other outbreaks. More than 700,000 people, for instance, are suspected of being infected with the virus in South America, Central America and the Caribbean since it appeared there, according to the Pan American Health Organization.
An outbreak of several thousand people in Florida could swamp existing medical facilities, putting at risk the state’s large elderly population, according to Tabachnick.
“Ten thousand cases would be a disaster in the terms of, these are people that are sick enough that they’re reporting to their doctors in the hospital,” he said by telephone. “So even our medical facilities could be overwhelmed.”
Other medical experts suggest that when mosquitoes disappear during the Florida winter, any outbreak will lessen. Still, it could remain a problem in areas of the state that have already been susceptible to other mosquito diseases, Weaver said in a telephone interview.
“I don’t think we’ll see outbreaks that large,” Weaver said, referring to the outbreaks in the Caribbean and Central America. “But we’ll see small focal outbreaks where an infected traveler comes home to their community.”
In part, the disease spread through the Caribbean and Central America because many countries in that region lack the financial resources or sophisticated mosquito killing systems needed to prevent major outbreaks, according to Durland Fish, a professor of epidemiology at Yale University who studied Chikungunya’s spread on the Caribbean island of Dominica.
Even with money and insect-killing expertise, Chikungunya may be hard to contain, according to Fish. The two types of mosquitoes that carry the virus tend live to among humans, inside people’s houses, he said. That’s unlike West Nile virus, which is spread by a mosquito that lives outside.
“So you have to get inside the houses and spray them with insecticide,” Fish said. In Dominica “we tried to isolate people that were sick with a bed-net so mosquitoes couldn’t feed on them and get infected.”
Fish said officials didn’t have the proper kind of insecticide or enough bed-nets to contain the spread of Chikungunya. The disease peaked on the island toward the middle of the year, waning after enough people who contracted the illness built up immunity, he said.
In Florida similar efforts to stop Chikungunya early on have faltered. Mosquito control efforts have been “particularly unsuccessful,” Tabachnick said. His laboratory has worked to convince people to remove standing water containers from their yards, such as buckets or clogged gutters, where Chikungunya-carrying mosquitoes lay eggs.
People in Florida “don’t see it as an imminent threat,” he said. “By the time it becomes an imminent threat it’s too late.”
The Florida Department of Health and the CDC have issued warnings on the illness and urged people to avoid mosquito bites if they become infected with Chikungunya, since that can infect the mosquitoes, and in turn spread the disease to more people. Tabachnick and Fish also expressed concerns about these efforts.
“I think that the health department and the vector control people -- the mosquito control people -- have to work very closely together, which is I think something that they don’t do very well here,” Fish said. “That’s probably something we haven’t had a lot of experience at.”
In response to questions about its collaborative efforts to control Chikungunya, health department spokeswoman Sheri Hutchinson said the department has a long history of working with the mosquito control agencies.
“As a member of Florida’s Mosquito Control Council, the department collaborates with Florida mosquito control district leaders to monitor and address arbovirus concerns,” she said in an e-mail.