Japanese Encephalitis

What is Japanese encephalitis?

Japanese encephalitis is a mosquito-borne viral infection that can affect the brain and nervous system. The disease occurs most commonly in Asia, including Japan, China, India, and Southeast Asia. Encephalitis means inflammation of the brain, which can cause headache, fever, vomiting, and abnormal brain function.

How is Japanese encephalitis spread?

The virus is transmitted to humans by the bite of an infected mosquito. These mosquitoes first acquire the virus from infected pigs and wild birds. The disease is not transmitted person-to-person.

What are the symptoms of Japanese encephalitis?

Most individuals who are infected have no symptoms. Individuals with mild disease have fever and headache, while more serious infections include stiff neck, lethargy, tremors, and confusion. The disease can be serious and has a 30% fatality rate and a 30% rate of serious neurologic complications, including seizures, paralysis, and coma.

How is Japanese encephalitis diagnosed?

Physicians will suspect the diagnosis based on a patient’s symptoms and travel and vaccination history. There are blood tests available that can confirm the diagnosis.

Is treatment available?

There is no treatment for Japanese encephalitis. Fluids are encouraged and medications may be recommended to lower fever.

Can Japanese encephalitis be prevented?

There are two important strategies to prevent this disease. First, travelers should take all necessary precautions to repel and avoid mosquitoes. Secondly, there are two vaccines currently available in the United States for travelers at risk. The need for vaccination depends upon the traveler’s itinerary, length of stay, activities, and disease trends in the destination.

Do international travelers need to be protected?

Travelers at risk should discuss the pros and cons of vaccination with their Travel Clinics of America physician. While the disease is uncommon, it can strike hard, so travelers to rural regions where Japanese encephalitis is known to occur should be informed about their risk of infection several weeks before departure. Japanese encephalitis vaccines require more than one injection and these must be completed prior to departure.