{"id":23148,"date":"2026-08-18T12:35:55","date_gmt":"2026-08-18T06:50:55","guid":{"rendered":"https:\/\/eng.dragonmedia.com.np\/?p=23148"},"modified":"2026-08-18T12:35:55","modified_gmt":"2026-08-18T06:50:55","slug":"japanese-encephalitis-nepals-changing-risk-and-why-adults-need-greater-vigilance","status":"publish","type":"post","link":"https:\/\/eng.dragonmedia.com.np\/?p=23148","title":{"rendered":"Japanese Encephalitis: Nepal\u2019s Changing Risk and Why Adults Need Greater Vigilance<\/strong>"},"content":{"rendered":"

Adrian Mercer<\/strong><\/p>\n

As mosquito-borne diseases increase during Nepal\u2019s monsoon season, Japanese encephalitis is once again emerging as a serious public health concern. Once viewed primarily as a disease affecting children in the Tarai, it is now being reported among adults and in hill districts as well, suggesting that Nepal\u2019s traditional risk map is changing.<\/p>\n

Japanese encephalitis is a viral disease that can cause severe inflammation of the brain. It is transmitted to humans through the bite of infected Culex mosquitoes. Pigs and water birds play an important role in the natural transmission cycle of the virus, but the disease does not spread directly from pigs to humans. Infected mosquitoes are the main vector, and the disease is not normally transmitted from person to person.<\/p>\n

One of the most difficult aspects of Japanese encephalitis is that most people infected with the virus develop no obvious symptoms. According to the World Health Organization, only about one in 250 infections progresses to severe disease. But once the infection affects the brain, the consequences can be extremely serious.<\/p>\n

The illness may begin with fever and headache before progressing to high fever, severe headache, neck stiffness, confusion, unusual behaviour, difficulty speaking or walking, seizures, loss of consciousness or even coma. When such symptoms appear, waiting at home for the fever to subside can be dangerous. The patient should be taken to a hospital immediately.<\/p>\n

Among patients who develop severe Japanese encephalitis, the fatality rate can reach 30 percent. Many survivors may also experience long-term neurological complications, including problems with memory, speech, hearing, vision, behaviour, physical weakness or recurrent seizures.<\/p>\n

There is no specific antiviral medicine that directly eliminates the Japanese encephalitis virus. Hospital treatment is mainly supportive, aimed at stabilising the patient, controlling fever and seizures, maintaining breathing and managing other complications.<\/p>\n

For this reason, prevention is far more important than treatment.<\/p>\n

Nepal\u2019s Changing Risk<\/h3>\n

Nepal carried out extensive vaccination campaigns against Japanese encephalitis after major outbreaks and later incorporated the vaccine into the routine childhood immunisation programme. These measures helped significantly reduce the burden of the disease among children.<\/p>\n

A new challenge, however, is becoming increasingly visible.<\/p>\n

Adults who were not covered by earlier vaccination campaigns or who never received the vaccine may now represent an important immunity gap.<\/p>\n

A Nepal-focused study published in 2026 indicated that the epidemiology of Japanese encephalitis is changing. A disease once concentrated mainly among children and in the Tarai is increasingly being detected among susceptible adults, particularly age groups not covered by earlier immunisation campaigns, as well as in hill areas.<\/p>\n

Analysis of recent government data has also shown that a substantial proportion of infections and deaths occurred among people over the age of 15, with many of the fatalities reported among those over 40.<\/p>\n

This carries an important public health message: Japanese encephalitis can no longer be regarded simply as a childhood disease.<\/p>\n

The government has moved to expand vaccination in 11 districts considered to have a high disease burden: Chitwan, Kailali, Tanahun, Dang, Jhapa, Kapilvastu, Morang, Rupandehi, Sunsari, Rautahat and Sarlahi. Adult-focused vaccination campaigns have also been conducted among high-risk groups in areas including Nawalparasi East and Chitwan.<\/p>\n

Adults who have never been vaccinated, however, should consult local health facilities or medical professionals to determine whether vaccination is appropriate for them. The decision may vary depending on age, previous vaccination history, place of residence and individual health conditions.<\/p>\n

Who Should Be More Vigilant?<\/h3>\n

People living near rice fields, stagnant water, pig-farming areas and environments favourable to Culex mosquito breeding may face greater exposure. The monsoon and post-monsoon periods require particular vigilance.<\/p>\n

However, it is no longer appropriate to consider the risk confined to rural areas of the Tarai. Cases have also been detected in Nepal\u2019s hill districts.<\/p>\n

Environmental change, irrigation, changing patterns of land use and the expanding geographical range of mosquitoes may all contribute to changes in the distribution of the disease.<\/p>\n

At the individual level, preventing mosquito bites remains essential. People should wear clothing that covers the body, use appropriate mosquito repellents, sleep under mosquito nets, prevent stagnant water from accumulating around homes and reduce opportunities for mosquitoes to enter living spaces.<\/p>\n

Mosquito control alone, however, is not sufficient to control Japanese encephalitis. Maintaining high vaccination coverage in risk areas remains one of the most effective public health measures.<\/p>\n

Do Not Dismiss It as Just Another Fever<\/h3>\n

During Nepal\u2019s monsoon season, dengue, typhoid, malaria and several other infections can also cause fever. Japanese encephalitis therefore cannot be distinguished from other illnesses on the basis of fever alone during the early stages.<\/p>\n

But fever accompanied by altered consciousness, unusual behaviour, extreme drowsiness, slurred speech, neck stiffness, weakness in part of the body, seizures or loss of consciousness should never be treated as an ordinary viral fever.<\/p>\n

These may be warning signs that the brain is being affected and require urgent medical evaluation.<\/p>\n

The challenge posed by Japanese encephalitis today is not simply the number of infections. The larger question is whether Nepal\u2019s vaccination policy, disease surveillance and public awareness are adapting quickly enough as the age profile and geographical distribution of risk change.<\/p>\n

Nepal has achieved important success by expanding childhood vaccination. The next challenge is to address adults who were missed by previous immunisation programmes, newly emerging risk areas and changing patterns of transmission associated with the monsoon.<\/p>\n

For the public, the message is simpler.<\/p>\n

Japanese encephalitis may be relatively uncommon, but once it becomes severe, the consequences can be devastating. Protect yourself from mosquito bites, check the vaccination status of yourself and your family, and seek hospital care immediately if fever is accompanied by neurological symptoms or changes in consciousness.<\/p>\n

\n\t\t\t
\n\t\t\t <\/div><\/div>\n\t\t