What is Japanese encephalitis?

Japanese encephalitis is a rare but serious viral infection. It’s spread through mosquito bites. The virus starts with a mosquito biting an infected pig or bird, then biting a human and transmitting the disease. It can’t be passed from person to person.

Japanese encephalitis isn’t found in the UK. It’s most commonly found in:

India
China
Japan
South Korea
Indonesia
Southeast Asia for example Thailand, Malaysia and Vietnam

It’s rare for travellers to get Japanese encephalitis, especially if you’re only travelling for a short time. You’re at higher risk of catching it if you’ll be staying in rural areas and staying near to rice fields or pig farms for one month or longer.

Signs & symptoms

If you have Japanese encephalitis, you won’t always have symptoms. If you do get symptoms, they’ll usually be mild and like the flu.

Some of the flu-like symptoms include:

A headache
A fever
Nausea
Being sick
Tummy pain

The symptoms do normally go away on their own, but one in every 250 people develop more severe symptoms. This usually takes place five to 15 days after infection when it spreads to the brain.

Severe Japanese encephalitis symptoms can include:

A severe headache
Confusion
Inability to speak
Seizures (fits)
Stiff neck
Uncontrollable shaking of body parts
Not being able to feel or move parts of your body (paralysis)
Muscle weakness

You need to ask for an urgent GP appointment or call NHS 111 if you’ve recently travelled to an area where Japanese encephalitis is present and you have symptoms like:

Tummy pain
Nausea
Being sick
A fever
A headache

Make sure to let them know where you’ve travelled to and if you were bitten or think you were bitten by a mosquito.

Make sure to call 999 if you or someone else has severe Japanese encephalitis symptoms.

As these can be signs of many different diseases, you should seek immediate medical attention if you become unwell with flu-like symptoms and any of the symptoms listed whilst away or on your return.

Treatment

Japanese encephalitis has no cure; however treatment can be given to help the body as it fights off the infection. Symptoms usually require hospital treatments as it can be life-threatening. You might be given fluids, oxygen and medication.

In some cases, Japanese encephalitis can cause paralysis, seizures and loss of speech.

Prevention

The Japanese encephalitis vaccination is advised if you’re travelling to areas where it’s found.

It’s also important to protect yourself from being bitten by mosquitos. To help prevent bites, you should:

Use insect repellent on any exposed skin, ideally this should contain at least 50% DEET
Sleep under a mosquito net which has been treated with an insecticide
Wear long sleeved tops, trousers or long skirts, socks and shoes to help protect your skin from mosquito bites

Japanese encephalitis vaccination

The vaccination for Japanese encephalitis is advised if you’re travelling to an area where it’s found. It’s given in two doses for protection. The second dose can either be given 28 days after the first, or, when time is short, seven days after the first (an ‘accelerated’ schedule). The two doses should be completed at least seven days before your departure.

If you’re at higher risk of the disease, you should consider being vaccinated. It’s particularly important if:

You’re travelling to a high-risk country during rainy season
You’re visiting rural areas like rice fields, marshlands or animal farms
You’re likely to be doing activities that could increase your risk like camping

How long does the Japanese encephalitis vaccination last?

If you’re at prolonged risk of infection, you should have a booster injection 12 to 24 months after the initial vaccination.

Japanese encephalitis - vaccination

Lalys Chemist