Japanese Encephalitis

What is Japanese Encephalitis?

Japanese encephalitis is a viral infection of the brain that is transmitted by mosquito bites. It is most prevalent in rural Southeast Asia, the Pacific islands, and the Far East, but is rare among travellers.

The virus is found in pigs and birds. When mosquitoes bite infected animals, the virus is passed to the mosquitoes. It can't be passed on from one person to another.

Japanese encephalitis presently has no cure. Treatment entails assisting the body's functioning as it attempts to fight off the illness.

The individual is usually admitted to the hospital so that fluids, oxygen, and medication can be administered.

What are the main risk factors for Japanese Encephalitis?

There are various behaviors that can raise your risk of infection, including:

• residing or travelling for an extended period in high-risk locations
• visiting rural areas, especially during the rainy season
• camping, cycling, or working outside in rural areas

High-risk Risk areas for Japanese Encephalitis

There are cases of Japanese encephalitis across Asia and beyond. Most cases occur in:

• China
• Myanmar (Burma)
• Thailand
• Vietnam
• Cambodia
• Laos
• Nepal
• India
• Philippines
• Sri Lanka
• Malaysia
• Indonesia

Mass immunizations have made Japanese encephalitis rare in Japan, despite its name.

Main symptoms of Japanese Encephalitis​

Most people infected with the Japanese encephalitis virus have either no symptoms or mild, temporary symptoms that are frequently misdiagnosed as influenza.

As the Japanese encephalitis virus progresses to the brain, however, approximately 1 in 250 affected individuals suffers more severe symptoms.

This often occurs between 5 and 15 days following infection.

Symptoms may consist of:

• a high temperature (fever)
• seizures (fits)
• a stiff neck
• Confusion
• Inability to talk
• Uncontrollable shaking of the body (tremor)
• Weakness or paralysis of muscles

One in three of those who develop severe symptoms die from the infection.

In survivors, these symptoms tend to gradually improve.

However, full recovery can take many months, and up to fifty percent of survivors are left with chronic brain damage.

This may result in tremors and muscular twitches, personality changes, muscle weakness, learning difficulties, and paralysis of one or more limbs.

Ways to minimise the risk of Japanese Encephalitis during travel

The most important aspect of prevention is avoiding getting bitten by mosquitoes, particularly after dark, when these particular mosquitoes are most active.

It is recommended that people who are at risk use insect repellents, wear appropriate clothing, and sleep under mosquito nets.

If you are travelling to a high risk area, consider getting the vaccine. Book a consultation 6 to 8 weeks before travel to ensure that you have enough time to get the necessary vaccination doses.