The mosquito-borne chikungunya virus is known to cause fever and severe pain in affected people but findings of a new study revealed that infection may also result in potentially fatal brain inflammation, with infants and older adults being the most vulnerable to this risk.
In a new study published in the journal Neurology on Nov. 25, researchers looked at the 2005-2006 chikungunya outbreak that sickened over 300,000 people. The epidemic occurred on Reunion Island, east of Madagascar in the Indian Ocean.
They found that chikungunya led to 24 people developing encephalitis, an inflammation of the brain. Four of the affected people died from the infection. The researchers revealed that brain inflammation from the chikungunya virus tend to be common among infants below age one and people who are 65 years old and older.
Before the Reunion Island outbreak, chikungunya was believed to be a nonfatal virus that rarely causes encephalitis. The outbreak, however, saw 57 patients falling ill to diseases of the nervous system including the 24 who developed the encephalitis.
Of those who contracted encephalitis, 17 percent died and up to 45 percent of the children ended up with long-term disabilities such as behavioral changes and difficulty in thinking and remembering as a result of brain inflammation.
"These data are of paramount importance for public health stakeholders and policy makers, because owing to global climate warming, chikungunya threatens many countries, including those in the Western world, with possibilities of epidemics in Southern Europe, Southern Central, and even North America," said study researcher Patrick Gérardin, from Central University Hospital in Saint Pierre, Reunion Island.
To date, no vaccine and treatments are available to prevent and treat chikungunya. The best treatment right now is supportive care.
People can reduce their odds of getting infected by the chikungunya virus by avoiding areas that are infested by mosquitoes, wearing protective clothing or using effective mosquito repellents.
Symptoms of the condition include fever and joint pain. Most people recover within a week but for some patients the joint pain may continue for several years. The researchers said that those who develop encephalitis may be treated with steroids in order to reduce the swelling of the brain.
Despite the findings of the study, experts said that encephalitis does not often occur even among those infected by the chikungunya virus.
"It's important to keep in mind that encephalitis is a rare disease," said Gaurav Guliani, assistant neurology professor at the University of Minnesota. "It's good to be aware of it, but it's important to know that it's rare."
