Japanese Encephalitis Virus (JEV) originates from the Flavivirus family, from which dengue, yellow fever, and West Nile virus also come from. It is spread on by the Culex mosquito and can affect humans, horses, and pigs. Mosquitoes are only the vectors or the passers of the disease. Wild birds are identified as the natural hosts of JEV.
It was first documented in 1871 in Japan and since then has passed on to neighboring countries. More than 3 billion individuals are at risk since about 24 countries in Southeast Asia and Western Pacific region have been exposed to this disease. There are an estimated 68,000 clinical cases annually globally with about 13,600 to 20,400 deaths.
Individuals in rural areas are exposed to higher risk of JEV since this is where the virus is common, particularly in areas where rice is grown. It is more likely to affect children, since adults become naturally immune to the disease as they get older. The transmission of this disease varies from place to place.
In temperate regions, the risk of transmission increases during the summer and early fall (May to September). In subtropical and tropical areas, it depends on the rainfall and patterns of bird migrations. There are also some tropical areas wherein transmission may occur at any time of the year, based on the agricultural practices of the community.
References: Japanese Encephalitis. (2015, August 05). Centers for Disease Control and Prevention. Retrieved from https://www.cdc.gov/japaneseencephalitis/prevention/. ; Kraft, S. (2016, July 12). What is Japanese Encephalitis? Medical News Today. Retrieved from https://www.medicalnewstoday.com/articles/181418.php. ; Japanese Encephalitis. (2017, June). Valneva. Retrieved from https://www.valnevauk.com/disease/japanese-encephalitis/#. ; Japanese Encephalitis. (2015 December). World Health Organization. Retrieved from http://www.who.int/mediacentre/factsheets/fs386/en/. ; 13 Natural Ways To Keep Mosquitoes Away. (2016, July 28). Natural Living Ideas. Retrieved from http://www.naturallivingideas.com/13-natural-ways-to-keep-mosquitoes-away/.