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[[Category:To Do - Steph]]
[[File:JEV Litter.jpg|thumb|200px|right|Litter from a JEV infected sow showing two mummified piglets. Copyright CFSPH Iowa State]]
Also Known As – '''''JE – Japanese B Encephalitis - Hydrancephaly'''''
Caused By – ''Japanese Encephalitis Virus – JEV – Japanese B Encephalitis Virus – JE Virus''
==Introduction==
Japanese Encephalitis is caused by a '''[[Culicidae | mosquitoe-borne]] [[Flaviviridae | flavivirus]]''' and affects a wide range of species including ruminants, carnivores, birds and humans.
It is best known for causing reproductive failure in sows and central nervous system disease in horses.
This disease is '''notifiable''' to the World Organisation for Animal Health [http://www.oie.int/ (OIE)]
JE is '''zoonotic''', epidemics having been recorded in Japan, Korea and India during the mosquito season. Although disease is usually mild or subclinical, fatal encephalitis can develop in children.
==Distribution==
JE has a number of '''insect vectors''', mainly '''[[Culicidae | mosquitoes]]'''.
Distribution is restricted to '''South-East Asia'''.
'''Birds''', particularly '''herons''', are '''maintenance hosts''' for JEV while '''pigs''' are '''amplifier hosts.'''
==Clinical Signs==
'''Abortion in pregnant sows''', stillbirths, male '''infertility''', lack of libido, small litter sizes and '''heat on palpation''' of the testes and scrotum.
'''Neurological''' disease in '''horses''' features trembling, ataxia, incoordination, opisthotonus, hypermetria, aggression, blindness.
Anorexia, inappetance and ill thrift.
Infection is usually subclinical in other species.
==Diagnosis==
'''Antibody titres''' can be detected serologically by Haemagglutination inhibition, '''[[ELISA testing | ELISA]]''', serum neutralisation and other methods. They can also be detected in foetuses.
'''Viral antigen''' can be demonstrated in '''brain, placenta and foetuses''' by Indirect Fluorescent Staining '''(IFAT)''' and Avidin-biotin staining.
On post-mortem of piglets from infected dams, '''hydrocephalus, hydrothorax''', subcutaneous oedema and necrotic foci within the organs are common. The meninges and spinal cord may be congested and cerebellar hypomyelinogenesis has been described. <ref> Morimoto, T. (1969) Epizootic swine stillbirth caused by Japanese encephalitis virus. Proc symposium on factors producing embryonic and fetal abnormalities, death, and abortion in swine. US ARS, 91-73:137-153</ref>
In male infected pigs, large amounts of '''mucoid fluid''' are present within the [[Testes and Epididymis - Anatomy & Physiology | '''tunica vaginalis''']] and the epididymis and tunic are '''fibrosed'''.
==Treatment==
'''No treatment''' is available in animals.
Human recombinant interferon has been used in human cases of JEV.
==Control==
'''Live attenuated vaccines''' are available against JEV.
Fly control is valuable but impractical.
==References==
<references/>
Animal Health & ProductIon Compendium, '''Japanese encephalitis virus datasheet''', accessed 06/06/2011 @ http://www.cabi.org/ahpc/
Animal Health & ProductIon Compendium, '''Japanese encephalitis datasheet''', accessed 06/06/2011 @ http://www.cabi.org/ahpc/