Update, July 2026: Assam is again reporting Japanese encephalitis deaths, with the toll tripling in the two weeks to 6 July 2026. See our latest report on the surge in Japanese encephalitis cases in Assam.

Current Situation in northeastern India

Three more Japanese encephalitis-related deaths have been confirmed by health officials in Assam, India. A total of 14 deaths has been notified in 2025. The outbreak is focused in districts located in Lower Assam, Northern Assam and Central Assam. The districts of Kamrup, Nalbari, Darrang, Golaghat and Nagaon were mentioned.

These areas are prone to outbreaks and offer ideal conditions for transmission during the wetter months of the year. Sporadic outbreaks have been identified in the region for over 50 years.

Health officials are urging people to control mosquitoes, get vaccinated and stay informed to help stop the spread.

Environmental and agricultural drivers of Japanese Encephalitis

Assam is very dependent on agriculture for economic activity. Rice is the main crop. It is also home to the largest population of pigs. Almost 18% of the country’s total pig population is in Assam.

Water, pigs and mosquitoes is a good recipe for endemic Japanese encephalitis. In a study of pig positivity for JE antibodies in 2018, almost 23% were found to be positive. In this study, the risk of disease was highest from June to September.

JE transmission, geography and global burden

Japanese encephalitis is a viral disease transmitted by mosquitos from birds and pigs to humans. It is the leading cause of vaccine preventable encephalitis in Asia.

Japanese encephalitis is a health concern in 24 countries in Southeast Asia and the Western Pacific region. More than 3 billion people live in endemic areas.

Environmental determinants of Japanese Encephalitis include climate, rainfall, temperature, water bodies and proximity to irrigation and pig farming. It is most prevalent in rural areas.

In temperate regions of Asia, transmission is seasonal, with peak cases of infection in the summer and autumn months. In the tropics and subtropics, transmission can occur year-round, peaking during the wet season.

Japanese Encephalitis risk level for travellers

For most travellers to Asia and parts of the Western Pacific, the risk of Japanese Encephalitis is low, particularly for short term visitors to urban areas. This risk is estimated to be less than 1 in a million per month of stay but will change according to season, destination, duration of travel and intended activities. The level of accommodation is important when assessing risk.

Japanese encephalitis vaccination is available to those considered more at risk. These would include expatriate workers (cumulative risk), long term backpackers and travellers off the beaten path.