Another Risk of Chikungunya

Chikungunya may cause severe brain infection in infants, elderly


A virus that is gaining ground in many parts of the world may lead to a severe brain infection in some patients.

The virus is chikungunya. And it might lead to encephalitis, a potentially deadly brain infection, in infants and those older than 65, a new study found.

The study, published Nov. 25 in the journal Neurology, found that the rate of brain infection from the mosquito-borne virus may be higher than previously thought. And when you're talking about a virus that has rapidly broken out in the Caribbean, Africa, Central America and Asia, a risk of brain infection may be pretty serious.

"Since there is no vaccine to prevent chikungunya and no medicine to treat it, people who are traveling to these areas should be aware of this infection and take steps to avoid mosquito bites, such as wearing repellent and long-sleeves and pants if possible," said study author Patrick Gérardin, MD, PhD, of Central University Hospital in Saint Pierre, Reunion Island, in a press release.

Chikungunya is spread primarily through mosquitoes. Common symptoms include joint paint, fever, swelling, rash and headache. The disease often resolves in less than a week, but symptoms like joint pain can persist much longer in some cases. In the last year, Mexico reported roughly 7,000 cases. The United States reported one locally transmitted case last July.

For this study, Dr. Gérardin and team looked at an outbreak on Reunion Island that occurred in 2005. The virus sickened roughly 300,000 people on the island. Twenty-four of them developed encephalitis — 8.6 patients for every 100,000.

So the overall rate of brain infection tied to chikungunya was fairly low. But when Dr. Gérardin and colleagues looked at brain infection in infants and patients over 65, the incidence began to rise. Among infants, 187 for every 100,000 who contracted chikungunya developed encephalitis. For the older patients, that rate was 37 per 100,000.

Not everyone who has encephalitis dies — 17 percent of the encephalitis patients in this study died — but the disease often leaves lasting behavioral and cognitive changes or defects.

"The consequences of this encephalitis seem to be particularly harmful in newborns," Dr. Gérardin said.

The best way to prevent chikungunya is to prevent mosquito bites, according to these researchers.

The Institut Pasteur, Inserm, LabEx and others funded this research. The authors disclosed no conflicts of interest.