What was once considered a disease limited to lowland Terai communities is now reaching higher elevations – including the Kathmandu Valley – where cases were reported in 2024, according to the Kathmandu Post newspaper. Experts link this shift to climate change.
A virus long regarded as confined to the rural fringes of Nepal is back – and appearing in unexpected places. Japanese Encephalitis (JE), a mosquito‑borne flavivirus notorious for causing brain inflammation and high fatality rates, has already claimed two lives and infected eleven others across nine districts since January 2025.
Human Toll Mounts
The latest casualties include a 49‑year‑old man from Kanepokhari in Morang district and a 17‑year‑old male from Bara district’s Devtal Rural Municipality. Of the eleven infected, four have recovered, while the remaining seven remain hospitalized. Notably, five of the infected are children, and data show that those aged 15 and above face a higher mortality risk—especially if unvaccinated.
This year’s cases span Morang, Bara, Jhapa, Saptari, Siraha, Sarlahi, Parsa, Nawalparasi West, and Chitwan districts – underscoring JE’s growing geographic reach, beyond the long‑established hotspots in the Terai region. Health experts caution that official counts are likely an underestimation, given that testing focuses largely on patients with severe symptoms.
In 2024, a wider outbreak had already unfolded – 23 fatalities and over 80 infections were registered across 30 districts, including one case in Kathmandu Valley.
Vaccination Gaps Exposed
Nepal incorporated the JE vaccine into its routine immunization program in 2015, but vaccination rates remain troublingly low. The data for 2025 reveal that only one of the infected was previously inoculated, four had not received the vaccine, and the vaccination status of the others remains unknown. Health professionals argue that, despite its limited impact on immediate outbreak control, vaccination builds vital immunity against future episodes.
JE is transmitted by infected Culex mosquitoes that thrive in rice paddies and standing water. Pigs and ducks act as natural amplifiers, while humans are dead‑end hosts – they don’t transmit the virus further.
The virus can kill up to a third of those who fall severely ill, and survivors often face lifelong neurological impairments. Symptoms include high fever, headaches, seizures, and loss of consciousness, usually emerging 5–15 days after infection.
Climate Change – Higher Ground, Higher Risk
What was once considered a disease limited to lowland Terai communities is now reaching higher elevations – including the Kathmandu Valley – where cases were reported in 2024, according to the Kathmandu Post newspaper. Experts link this shift to climate change, urban expansion, intensified agriculture, and evolving vector patterns.
Public health voices urge broadening vaccination campaigns – especially to cover older children and adults in emerging high‑risk zones like the hills and urban centres. Enhanced surveillance, improved laboratory access, and consistent awareness programs are equally vital.
Preventive measures – using repellents, wearing long sleeves, installing mosquito screens, and removing stagnant water – also remain key defences in the absence of specific treatment.
International Response Lags
Despite repeated appeals, international partners – including the World Health Organization and vaccine alliances – have not prioritized JE vaccine donations over the past year. With resource constraints, Nepal now looks to ramp up self-driven immunization campaigns, environmental controls, and public education drives.
As monsoon waters recede, the risk of JE may subside somewhat – but the shifts in geography, rising case counts, and persistent vaccine gaps signal a worrying trend. Without decisive action, JE could become entrenched in new regions and populations across Nepal.
Enhanced vaccination outreach, proactive surveillance, and community engagement will be the keys to curbing this creeping crisis – and protecting the country’s most vulnerable citizens.
