PARIS--A French island in the Indian Ocean is reeling from an explosive outbreak of a little-known viral disease. Today, the French National Institute for Public Health Surveillance said that an estimated 110,000 residents of Reunion, population 700,000, had been infected with the Chikungunya virus--almost 22,000 of them in the week from 6 to 12 February. Chikungunya is rarely fatal--of 52 patients who died, all but one were suffering from other diseases as well--but it can cause high fevers, rashes, and excruciating joint and muscle pains.
"It's a massive outbreak, it's absolutely alarming," says Stephen Higgs of the University of Texas Medical Branch in Galveston, one of a few dozen researchers around the world who studies Chikungunya virus, in the lab. Other Indian Ocean islands--including Mauritius, the Seychelles, and the Comoros--have also have seen cases, although far fewer.
"Chikungunya"--often shortened to "chik" by scientists--is a Swahili word meaning "that which bends up," a reference to some victims' inability to walk upright. The disease occurs primarily in Southeast Asia, the Indian subcontinent, and East Africa. Preliminary sequencing of virus isolates from Reunion at the Pasteur Institute in Lyon, France, suggests that the virus was imported from East Africa, says Pasteur virologist Nathalie Pardigon.
It's unclear why the outbreak is so ferocious. One factor, says virologist Charles Calisher of Colorado State University in Fort Collins, may be that the virus is hitting Reunion for the first time, so almost no one has resistance.
The epidemic has triggered a wave of activity in French laboratories. Earlier this week, the French government announced a broad research effort that will search for new treatments and vaccines, as well as investigate basic virology and mosquito ecology and control.
Although doctors can treat the symptoms of Chikungunya with painkillers and anti-inflammatories, there are no specific drugs against Chikungunya; not is there a vaccine. The most promising candidate thus far has been an attenuated virus, developed in the 1980s by researchers at the U.S. Army Medical Research Institute for Infectious Diseases in Fort Detrick, Maryland, whose development fell flat in the '90s. The Reunion outbreak is "an opportunity to reactivate the research effort and to bring the vaccine to licensure," says Colonel David Vaughn, who heads the infectious disease research program at the U.S. Army Medical Research and Materiel Command.
A spokesperson for French health minister Xavier Bertrand confirms that the French government is in conversations with the U.S. health and defense departments. But much more work is needed on the vaccine, he cautions--for instance, to investigate side effects.