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Also Known As: '''''JE — Japanese B Encephalitis — Hydrancephaly — JEV — JE Virus'''''
Also Known As – '''''JE – Japanese B Encephalitis - Hydrancephaly'''''
==Introduction==
==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.
[[File:JEV Litter.jpg|thumb|200px|right|Litter from a JEV infected sow showing two mummified piglets. Copyright CFSPH Iowa State]]
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.
It is best known for causing reproductive failure in sows and central nervous system disease in horses.
==Distribution==
==Distribution==
JE has a number of '''insect vectors''', mainly '''[[Culicidae | mosquitoes]]'''.
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==
==Clinical Signs==
Key reproductive signs include '''Abortion in pregnant sows''', stillbirths, male '''infertility''', lack of libido, small litter sizes and '''heat on palpation''' of the testes and scrotum.
Key reproductive signs include '''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 and blindness.
'''Neurological''' disease in '''horses''' features trembling, ataxia, incoordination, opisthotonus, hypermetria, aggression and blindness.
==Diagnosis==
==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.
'''Antibody titres''' can be detected serologically by [[Agglutination|haemagglutination inhibition]], '''[[ELISA testing|ELISA]]''', serum neutralisation and other methods. Antibodies 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.
'''Viral antigen''' can be demonstrated in '''brain, placenta and foetuses''' by [[FAT|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>
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==
==Treatment==
'''No treatment''' is available in animals.
'''No treatment''' is available in animals.
Human recombinant interferon has been used in human cases of JEV.
Human recombinant interferon has been used in human cases of JEV.
==Control==
==Control==
'''Live attenuated vaccines''' are available against JEV.
'''Live attenuated vaccines''' are available against JEV.
Fly control is valuable but impractical.
Fly control is valuable but impractical.
{{Learning
{{Learning
|flashcards = [[Japanese Encephalitis Flashcards]]
|flashcards = [[Japanese Encephalitis Flashcards]]
}}
}}
==References==
==References==
Animal Health & ProductIon Compendium, '''Japanese encephalitis 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/
[[Category:To Do - CABI review]]
{{review}}
[[Category:Flaviviridae]]
[[Category:Zoonoses]]
[[Category:Pig Viruses]][[Category:Horse Viruses]]
[[Category:Reproductive Diseases - Pig]][[Category:Neurological Diseases - Horse]]
[[Category:CABI Expert Review]]