The deadly disease Japanese Encephalitis occurs mainly in the rural areas of China and Korea, but is also found in most countries of South and East Asia. Japanese encephalitis is caused by a Flaviviridae virus, which is transmitted by mosquitoes. Transmission of the disease is most likely during the summer months in temperate areas and during the rainy season and early dry season in tropical areas, when the mosquito populations are the highest. Most people who are infected show only mild symptoms or no symptoms at all. However, at advanced stages, the disease may be fatal.
Japanese encephalitis begins like flu with headache, fever, and weakness.
Gastrointestinal problems, including vomiting, as well as confusion and delirium may also be present. A vaccine has been developed, but there have been reports of serious allergic side effects in a small number of cases. About one in five people who receive the vaccine do experience some pain, redness and swelling at the injection site. In about one in 260 cases the vaccine causes a general rash, itching or swelling, especially of the extremities, face, lips, and throat. In rare cases, vaccinees may suffer shock or respiratory distress.