Japanese Encephalitis Vaccine Information

Japanese Encephaliti is transmitted by the bite of an infected mosquito just like malaria but it is a viral infection rather than a protozoan as in malaria. Mosquitoes become infected by feeding on domestic pigs and wild birds infected with the Japanese encephalitis virus. Infected mosquitoes then transmit the Japanese encephalitis virus to humans and animals during the feeding process although the illness cannot be passed on from person to person. Mild infections can sometimes occur without apparent symptoms other than mild fever with headache. More severe infection is marked by quick onset, headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, occasional convulsions (especially in infants) and spastic paralysis.

The risk of infection is greatest in long term visitors to rural areas, but the risk to short term visitors and visitors to major cities is small. There is an effective vaccine available and should be considered by anyone travelling to Asia for more than a month or visiting rural areas. However, precautions against mosquito bites will also greatly reduce the chances of infection. It is usually mild but in some cases it can cause inflammation (swelling) of the brain (encephalitis), leading to permanent brain damage or death. High risk areas include tropical north east Australia and East Asia - including China, Myanmar (Burma), Thailand, Vietnam, Cambodia, Laos, Nepal, India, Philippines, Sri Lanka, Korea, Malaysia, Indonesia and Singapore.