This year, close to 700 people have lost their lives in eastern India due to encephalitis, a disease usually caused by a viral infection and predominantly affecting children. Parts of Uttar Pradesh, Bihar, West Bengal and Assam have been severely struck by the disease, which causes inflammation in the membranes around the brain. In Tamil Nadu however, there have been few cases reported, says K. Kolandaisamy, director of public health. “This is because the Japanese encephalitis vaccine is administered in 13 districts in the State. We first administer it to all children below the age of 15 – as it mostly affects them — and then give it to all newborns as part of their routine immunisation,” he says.
Often, the Japanese encephalitis virus is transmitted through mosquitoes that usually breed in flooded rice fields. The virus then circulates in birds, uses pigs as an amplifying host and infects mosquitoes. When the infected mosquito population builds up, the disease spills over into the human population, according to the World Health Organisation’s website.
“The disease starts as a fever, and can be accompanied by altered sensorium – a feeling of drowsiness, disorientation and movement disorders. There is no specific treatment available – only supportive treatment is given. It can be fatal but a complete recovery is also possible. Some people are left with residual effects since it affects the brain,” said V. Ramasubramanian, an infectious diseases specialist.
With the Institute of Vector Control and Zoonoses as well as two other central government institutions monitoring cases and reports of infected mosquitoes, action can be taken quickly, Dr. Kolandaisamy says.