What is Japanese encephalitis?
Japanese encephalitis is a viral disease which, like malaria, is transmitted by mosquitoes. In many patients, Japanese encephalitis symptoms remain mild and the infection may even go unnoticed. However, in some cases, the virus causes severe symptoms and leads to serious complications.
Typical encephalitis symptoms include nausea and vomiting, seizures, headaches and confusion. The Japanese encephalitis virus affects the human brain and can lead to inflammation and swelling in the brain. In very severe cases, the infection can lead to brain damage.
There is no specific medication to treat and cure this type of encephalitis. Treatment usually focuses on relieving symptoms and supporting the immune system in its effort to fight the virus. A Japanese encephalitis vaccine provides medical protection for travellers at risk of catching the virus.
The World Health Organisation states, that there are roughly 70,000 new cases of Japanese Encephalitis worldwide each year. Half of these cases were in China, and around three quarters of all cases were children under the age of 15 years.
Side effects of the Japanese encephalitis vaccine
Allergic reactions are rare but can be serious. Common, less worrying side effects of the Japanese encephalitis vaccine, are redness and swelling at the site of injection, high temperature, nausea, dizziness and vomiting as well as abdominal pain. You may also experience muscle pain. These side effects should pass quickly.
Japanese encephalitis is primarily found on the Asian continent. High risk countries include China, Cambodia, India, Indonesia, Korea, Laos, Malaysia, Myanmar, Nepal, Philippines, Singapore, Sri Lanka, Thailand and Vietnam. Your risk of encephalitis in some of these countries will vary depending on the time of year of your visit. Due to the increased number of mosquitoes, the risk of encephalitis can be higher during the rainy seasons.
Generally, the risk for travellers is regarded as relatively low. However, travellers visiting remote areas and backpackers who spend prolonged periods of time outdoors have a higher risk of infection, as do children.
Spending time in a location close to pig farms or rice fields also increases your risk of contracting the virus, as mosquitoes thrive in damp areas and can pass the virus from animals to humans.
Your pharmacist will be able to help you decide whether you require a Japanese encephalitis vaccination.
Preventing Japanese encephalitis
As with other illnesses transmitted by mosquitoes, you can protect yourself from Japanese encephalitis by avoiding mosquito bites. Insect repellent, mosquito nets and long-sleeved clothing will help you stay safe when travelling to an encephalitis area.
You may also wish to travel outside the rainy season to limit your exposure to mosquitoes and the infections they carry. The Japanese encephalitis vaccine is the safest option for prevention and provides over 90% protection against the virus.