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Avian encephalomyelitis is an infectious disease of viral origin that affects certain bird species.

Situation in America: 

Avian encephalomyelitis is a cosmopolitan disease, the incidence of which has nevertheless greatly diminished thanks to the vaccination of breeders. It is present in the Caribbean, probably in most of the islands.

Susceptible species: 

Chickens, turkeys and quails between the age of 6 days and 3 weeks

Etiological agent: 

Avian encephalomyelitis is caused by a Picornavirus, an RNA non-enveloped virus.

Methods of transmission

Infection by direct contact is not common.


The disease is primarily transmitted vertically, as the virus is excreted in eggs.


- In young birds: appearance of mild trembling of the head, progressive muscular ataxia, developing into paralysis, seated position on tibio-metatarsal joints

- In adults: If infected at the beginning of egg laying: mild but protracted decline in egg laying, decrease in fecundity and hatchability.

If infected during egg laying: sudden but brief decline in egg laying

Laboratory diagnosis: 

- Detection of the pathogenic agent through viral isolation or an ELISA test

- Detection of antibodies using an ELISA test



In infected areas, the isolation and elimination of affected animals


Inactivated virus vaccine (the only type allowed in France) for breeders before or during egg laying


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