Japanese Encephalitis

What is Japanese Encephalitis?

Japanese Encephalitis (JE) refers to encephalitis, or infection and swelling of the brain, caused by the JE virus (JEV). JE is a serious and sometimes fatal disease. It is spread by mosquitoes and is found throughout Asia.1,2 Infection with the JE virus does not always result in disease but when it does the outcomes tend to be severe and can be long lasting.

JE usually begins with flu-like symptoms, such as high fever, chills, tiredness, severe headache, nausea, and vomiting.1 It can evolve to paralysis and coma, and can also cause serious, long-term consequences, such as physical or intellectual disability, or even death.

If you are traveling to Asia on business, to visit friends and family, or for vacation, you may be at risk.

JE is a common disease in Asia

JE is widespread across Asia and parts of the western Pacific region. The JE virus-carrying mosquitoes are usually found in the more rural areas of Asia (where there is pig farming or stagnant water from rice farming), but they can also be found on the outskirts of cities and in many popular travel destinations.

Each year, between 30,000 and 50,000 cases of JE are reported among Asian residents.2 Approximately 30% of these cases lead to serious, long-term illness, and 30% result in death.

Because JE is common in some places and can have grave consequences, many countries have childhood vaccination programs to protect their residents.

Travelers may be at risk

Travelers visiting areas where JE is endemic may be at risk of infection. The overall risk of getting JE is relatively low, however, it tends to increase when you stay for longer periods of time, spend time in rural areas and if you travel during the peak transmission season (often the wet season).

However, the risk to travelers is somewhat unpredictable and travelers have contracted JE on short visits, in or near cities and outside of peak transmission seasons.

Once someone contracts JE, there is no specific treatment that can cure the disease.1 Treatment for JE can only control symptoms to reduce the number of disabilities and deaths.

Because the risk of contraction is unpredictable and the consequences can be serious, the best strategy against JE is prevention of infection.

How you can protect yourself

The best way to protect yourself against JE is through vaccination, which has been proven to be effective in controlling JE both among people who live in Asia and among travelers to affected regions.1 Bed nets and screens can also help, but offer only limited protection, because the mosquitoes that carry the JE virus are active during daylight hours. Bed nets and screens are still useful, however, in protecting against other mosquito-borne illnesses.

If you are planning to travel to Asia, ask your health care provider about vaccination. Be prepared to protect yourself. Get vaccinated.