The chikungunya virus can cause fatal brain infection particularly for infants and people over the age of 65, according to a new study.
The disease is transmitted through mosquito bites, and its symptoms include fever and joint pain, which usually lasts for a week. These symptoms are sometimes accompanied by headache, rash, swelling of the joints and muscle pain, according to the U.S. Centers for Disease Control and Prevention.
Brain infection, or encephalitis, is one of the consequences of the infection. To determine the incidence rate of encephalitis among infected patients, the researchers reviewed data from a chikungunya outbreak that occurred on Reunion Island from 2006 to 2007, which affected a total of 300,000 people. They also investigated if patients who displayed neurological symptoms because of the infection were still affected after three years.
The researchers found that 24 people had encephalitis during the outbreak. This translates to a cumulative incidence rate of 8.6 cases per 100,000 people. Encephalitis was observed more in infants than in older adults over 65 years old. In infants, the incidence rate was 187 cases per 100,000 people, while in older adults, the incidence rate was 37 cases per 100,000 people.
"These numbers are both much higher than the rates of encephalitis in the United States in these age categories, even when you add together all the causes of encephalitis," lead researcher Dr. Patrick Gérardin from the Central University Hospital in Saint Pierre, Reunion Island said in a press release.
About 30 to 45 percent of patients with encephalitis from chikungunya infection had symptoms that persisted for years, such as dementia in older adults and memory skill and thinking problems in infants. Meanwhile, the death rate for those who developed encephalitis was 17 percent.
"The consequences of this encephalitis seem to be particularly harmful in newborns," Gérardin noted.
Gérardin said that people traveling to areas where chikungunya infections have been reported should take measures to protect themselves against mosquito bites, particularly because there is no vaccine against the disease at this time.
Outbreaks of the disease have occurred in Asia, Africa and Europe, but it was first detected in the Americas in 2013, specifically in the Caribbean. In the U.S., most cases of chikungunya infection were acquired by people during their travels. However, in 2014, the first locally transmitted case of the virus was reported in Florida, according to the CDC.
The study was published online Nov. 25 in the journal Neurology.
