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Viral infections of respiratory tract. Newcastel disease virusAvian influenzaAvian infectious bronchitis virusAvian laryngotracheitis disease virusAdenoviruses. Avian infectious bronchitis virus. Many strains (differ in antigenic properties and virulence) - mutations and recombinationAffects
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1. Avian infections
2. Viral infections of respiratory tract Newcastel disease virus
Avian influenza
Avian infectious bronchitis virus
Avian laryngotracheitis disease virus
Adenoviruses
3. Avian infectious bronchitis virus Many strains (differ in antigenic properties and virulence) - mutations and recombination
Affects young animals from 3 weeks
Maternal antibodies control infection for 3 weeks
Suffocation, cough, sternutation, urate plug, drop of lay, clinical signs last for 10 14 days
4. Avian infectious bronchitis virus Horizontal spread
Rapid spread high concentration of animals
Vertical transmission not demonstrated
Virus replicates in epithelial a subepithelial cells of repiratory tract and kidney (nefropathogenic strains)
Virus persistence and long term shedding
5. Avian infectious bronchitis virus - diagnostics Tracheal swabs till 14 days in chicken, 7-10 days in older, 2-3 weeks in nefropat. strains
Virus isolation in acute phase of the disease
CAM (2-3 passages)
tracheal explantates (ciliostasis in 2-3 days
Variant strains and Ag mutants sentinel SPF animals
6. Avian infectious laryngotracheitis virus Acute disease of chicken, pheasants (3-9 month)
Respiration problems, bloody mucous secretion
Conjunctivitis - panophtalmitis
Mild - peracute disease
Antigenic uniformity, strains differ in virulence
Impact of environment (iritation of resp.tract, low temperature, concurrent infections)
7. Avian infectious laryngotracheitis virus Virus latency in infected and vaccinated animals
Rezidual pathogenicity of vaccine strains
Cell immunity non-transmissible to the newborns
8. Avian infectious laryngotracheitis virus Samples: 4-6 living animals
trachea, larynx - chilled, not frozen
Diagnostics
I.N. inklusions - trachea
IF test trachea
Izolation on EE (CAM), IFA identification
Differentiation of vaccine and field strains by REA
9. Newcastel disease virus Different pathotypes of the virus
Velogenic (viscerotropic and neurotropic)
Mezogenic
Lentogenic
Serologically unique
Respiratory signs in velogenic and mezogenic strains
10. Newcastel disease virus Velogenic strains respiratory signs (edema of the neck, head), diarhea, neurological signs, bleeding, almost 100% mortality
11. Newcastel disease virus Diagnostics
Izolation: embryonated eggs
Detection: hemagglutination, PCR
Samples: lungs, spleen, brain, trachea.
Indirect detection: hemagglutination inhibition test (HIT) a virus neutralizing test (VNT)
12. THE RESPIRATORY TRACT