India: Elevated Japanese encephalitis activity identified in Bihar State

Event

Health officials identified 54 confirmed cases of Japanese encephalitis in Bihar State January-June 2022, surpassing the 38 cases reported during all of 2021.

Context

Japanese encephalitis (JE) vaccination coverage in India is estimated at 85-percent; many people likely missed their vaccinations during the first year of the COVID-19 pandemic, highlighting the importance of vigilant mosquito bite prevention measures. Bihar State health authorities reported 38 confirmed cases of JE in 2021 and 29 cases in 2020. Risk of JE infection in northern India is highest July-December.

Japanese encephalitis is a viral infection of the central nervous system that is transmitted by the bite of mosquitoes that prefer rural and semi-rural areas and are most active from dusk to dawn. Most JE infections exhibit mild symptoms (flu-like) or none at all. However, in some individuals, there may be an acute progression to encephalitis (inflammation of the brain), which can be life-threatening. Symptoms typically appear 5-15 days after being bitten.

Advice

Consult a travel medicine provider before departure regarding Japanese encephalitis vaccination. Avoid mosquito bites and remove standing water to reduce the number of biting mosquitoes. Seek immediate medical attention if symptoms develop within two weeks of being in affected areas.