Assam is currently experiencing a surge in Japanese encephalitis (JE) cases. Health authorities have confirmed 91 cases across the state, and four people have died at Guwahati Medical College Hospital (GMCH) alone.
Why is there a surge in Japanese encephalitis cases in Assam?
Assam is considered one of India’s endemic regions for Japanese encephalitis. Each year, cases tend to peak between June and September, when monsoon rains flood rice fields and low-lying areas. This year, authorities have reported cases in Nalbari, Barpeta, Sivasagar, Kamrup, and Darrang, with GMCH treating the most severe patients.
According to a health department source, officials believe that in Nalbari district, the infection is likely spreading from pig settlements, while in Barpeta, birds are suspected to be the primary carriers of the virus following inspections in the affected areas.
What Is Japanese Encephalitis?
Japanese encephalitis is a viral infection that affects the brain. It is caused by the Japanese encephalitis virus (JEV), which belongs to the same family as dengue and West Nile viruses.
Most people infected with JEV do not feel sick. But in some cases, especially among children and older adults, the virus can travel to the brain and cause severe swelling, known as encephalitis.
Symptoms of Japanese encephalitis usually appear 5–15 days after a mosquito bite and can include:
- Sudden high fever
- Severe headache
- Neck stiffness
- Confusion or disorientation
- Seizures
- Tremors
- Coma
Severe illness can be fatal. According to the World Health Organization, 20–30% of people with severe JE die, and about 30–50% of survivors suffer long-term neurological problems, such as speech difficulties, muscle weakness, or learning disabilities.1
How Does Japanese Encephalitis Spread?
Japanese encephalitis does not spread from person to person.
Instead, it follows a mosquito–animal–human cycle:
- Culex mosquitoes (especially Culex tritaeniorhynchus) lay eggs in flooded fields, rice paddies, and stagnant water.
- These mosquitoes bite infected animals, mainly pigs and wading birds, which carry the virus.
- When the same mosquitoes bite humans, they transmit the virus into the bloodstream.
Living near pig farms and rice paddies greatly raises the risk of Japanese encephalitis infection, highlighting the need for focused public health measures in these areas.2
Who Is at Risk of Japanese Encephalitis?
Although anyone bitten by an infected mosquito can get JE, the following groups are most at risk:
- Children under 15 years old
- Elderly adults
- People living in rural or agricultural areas
- Individuals who are unvaccinated
- People who work outdoors during dusk and dawn
Even travelers visiting endemic areas for short periods are advised to take precautions.
How Can You Prevent Japanese Encephalitis?
There is no specific antiviral cure for JE, so prevention is the most important strategy.
1. Get Vaccinated
Vaccination is the most effective way to prevent Japanese encephalitis. India’s Universal Immunisation Programme includes the JE vaccine in high-risk districts, targeting children between 1–15 years.
Two doses of the vaccine are recommended for long-term protection. If you or your children have not been vaccinated, contact your nearest health center. Studies have shown that vaccination can reduce JE incidence by over 90% .3
While the risk for most travelers is low, vaccination may be recommended depending on your destination, travel plans, and activities.4
JE Vaccine Schedule
The vaccine most commonly used is IXIARO. It is given as a two-dose series:5
- The doses are usually spaced 28 days apart.
- Adults aged 18–65 years may get the second dose as early as 7 days after the first dose if necessary.
- Children aged 2 months to 17 years and adults over 65 years should receive the second dose 28 days after the first.
- The final dose should be completed at least 1 week before travel.
2. Avoid Mosquito Bites
Mosquito control is crucial. Here are steps to protect yourself:
- Use insecticide-treated bed nets while sleeping, especially for children
- Apply mosquito repellents containing DEET or picaridin on exposed skin.6
- Wear long sleeves and pants, particularly in the early evening and morning when Culex mosquitoes are most active.5
- Install screens on doors and windows to keep mosquitoes out.5
- Use electric mosquito repellents indoors.5
3. Control Mosquito Breeding
Reducing mosquito breeding sites around your home is critical. Here’s how:
- Drain standing water from buckets, flowerpots, old tires, and gutters.
- Keep rice fields and pig pens away from residential areas, if possible2
- Collaborate with local authorities to spray insecticides and fog high-risk areas.
- Clear vegetation around water bodies to reduce mosquito resting sites.
Community involvement is essential. If everyone participates, mosquito density can be significantly reduced.
What Should You Do If You Suspect Infection?
Early recognition and medical care can save lives. If someone develops:
- Sudden high fever
- Severe headache
- Confusion or difficulty staying awake
- Seizures
…take them to the nearest hospital immediately.
Doctors will provide supportive care to manage fever, seizures, and brain swelling. Immediate treatment improves the chances of survival and reduces complications.
Conclusion
As Assam fights a surge in Japanese encephalitis cases, health authorities are acting to curb the outbreak through mass vaccinations, mosquito control, and public education.
Whether you live in an affected area or plan to travel there, remember that prevention is your strongest defense. Stay aware, protect yourself against mosquito bites, and seek prompt medical care if symptoms arise. Together, coordinated public health measures and individual action offer the best hope of bringing this outbreak under control.
References
- Japanese encephalitis [Internet]. [cited 2025 Jun 29]. Available from: https://www.who.int/news-room/fact-sheets/detail/japanese-encephalitis.
- Kumari N, Medhi S, Talukdar AJ, Deka M, Kashyap P, Kalita MJ, et al. The epidemiological and neurological risk factors of Japanese encephalitis virus in the population of Assam, Northeast India. Journal of Experimental Biology and Agricultural Sciences [Internet]. 2022 [cited 2025 Jun 29]; 10(6):1366–75. Available from: https://jebas.org/ojs/index.php/jebas/article/view/668.
- Laskar MA, Das PJ, Basak M, Kalita JK, Mandal S. Japanese encephalitis in north-east, India: Pharmacotherapeutic perspectives. The Microbe [Internet]. 2025 [cited 2025 Jun 29]; 7:100357. Available from: https://www.sciencedirect.com/science/article/pii/S2950194625001256.
- CDC. Japanese Encephalitis Vaccine. Japanese Encephalitis Virus [Internet]. 2024 [cited 2025 Jun 29]. Available from: https://www.cdc.gov/japanese-encephalitis/prevention/japanese-encephalitis-vaccine.html.
- CDC. Preventing Japanese Encephalitis. Japanese Encephalitis Virus [Internet]. 2024 [cited 2025 Jun 29]. Available from: https://www.cdc.gov/japanese-encephalitis/prevention/index.html.
- Koren G, Matsui D, Bailey B. DEET-based insect repellents: safety implications for children and pregnant and lactating women. CMAJ [Internet]. 2003 [cited 2025 Jun 29]; 169(3):209–12. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC167123/.
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