Chikungunya can be debilitating especially for the high-risk groups, but it can also be life threatening as it's being linked to a deadly brain infection known as encephalitis.
A group of researchers studied the viral disease data for Chikungunya in Reunion Island, near the Indian Ocean. For about a year since 2005, at least 300,000 people were inflicted with the disease caused by a mosquito carrying the virus.
Based on their analysis, they discovered that at least 8 people out of 100,000 developed encephalitis, a kind of brain inflammation of no definite cause. However, studies believe that the brain swells or becomes inflamed due to an exposure to a virus. This virus may affect the brain directly, in which case it's called primary encephalitis, or it triggers a sort of allergic reaction that leads to brain swelling, a condition called secondary encephalitis. In this scenario, the viral infection is happening elsewhere.
High-risk groups, which refer to older people and young children, who are infected of Chikungunya have a much higher possibility of developing encephalitis. Using the same data, the researchers found out that as many as almost 200 babies per 100,000 can suffer from the brain infection. Older people, meanwhile, or those who are 65 years old and above have an incidence rate of 37 per 100,000 people.
Severe encephalitis is considered rare. Among those who were afflicted with Chikungunya, only 17% died from encephalitis. However, the effects of the brain inflammation can last for a couple of years with at least 30% of the patients developing disabilities even after they have fully recovered both from the brain infection and the viral disease. These include joint pain, which is one of the landmark symptoms of Chikungunya. If it's severe, a person may have trouble moving properly, thereby reducing quality of life and ability to work.