KLIM
 |  موضوع: Avian Encephalomyelitis  9/4/2011, 01:08 | |
| كل أنواع ال Avian Encephalomyelitis
السلام عليكم ورحمة الله وبركاته
Avian Encephalomyelitis
ونبتدي مع
Avian Encephalomyelitis Egg Drop
Introduction
Avian encephalomyelitis virus infection in laying bird causes inapparent
infection or drops in egg production. See Avian Encephalomyelitis,
Epidemic tremors for its effect in young birds. It affects chickens,
turkeys, quail, pheasants and occurs in most poultry-producing
countries. Morbidity 5-60%, mortality none. The means of transmission is
unknown but probably by faecal contamination of environment, feed,
water etc. with an oral infection route. Virus in faeces may survive 4
weeks or more. Predisposed by immunosuppression.
Signs
* Drop in egg production, small (5-10%) and lasting no more than 2 weeks.
* In breeders there may be a drop in hatchability of about 5%, and
there is serious disease in the progeny (see next section).
Post-mortem lesions
* None.
Diagnosis
History, rising titre to AE virus, subsequent disease in progeny if
breeders. Serology - The embryo protection test has been used in the
past, now Elisa is used more commonly. Differentiate from Infectious
Bronchitis, lentogenic Newcastle disease, EDS*76.
Treatment
None.
Prevention
Vaccination of breeders/layers at 9-15 weeks, attenuated or not. Immunity is usually long lasting.
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ودلوقتي مع الأهم وهو
Avian Encephalomyelitis, Epidemic Tremors
Introduction
Avian encephalomyelitis is a viral disease of the central nervous system
of chickens, pheasants, turkeys, and quail. It has a worldwide
distribution. Morbidity 5-60% depending on the immune status of the
majority of parents, mortality high. Vertical transmission is very
important, transmission occurs over about 1-2 weeks, some lateral. The
route of infection is transovarian with an incubation period of 1-7
days; lateral transmission is probably by the oral route, incubation
>10 days. Virus in faeces may survive 4 weeks or more.
Signs
* Nervous signs.
* Dull expression.
* Ataxia and sitting on hocks.
* Imbalance.
* Paralysis.
* Tremor of head, neck and wings. Tremor may be inapparent but is accentuated if chicks are held inverted in the hand.
Post-mortem lesions
* Gross lesions are mild or absent.
* There may be focal white areas in gizzard muscle (inconstant).
* A few recovered birds may develop cataracts weeks after infection.
* Microscopic - nonpurulent diffuse encephalomyelitis with perivascular cuffing.
Diagnosis
A presumptive diagnosis is based on the history, signs, and lack of
significant lesions. Histopathology is usually diagnostic and IFA,
and/or viral isolation may be carried out if required. The embryo
protection test has been used in the past, now Elisa is used more
commonly. Differentiate from Newcastle disease, vitamin deficiency (E,
A, riboflavin), toxicities, EE (especially in pheasant in the Americas),
Marek's disease, Mycotic Encephalitis, Brain abscess, Enterococcus
hirae infection.
Treatment
None.
Prevention
Vaccination of breeders at 9-15 weeks, attenuated or not. Immunity is long lasting.
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خالد الرواضيه
| | موضوع: رد: Avian Encephalomyelitis 9/4/2011, 01:37 | |
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