ThePoultrySite Quick Disease Guide
Avian Rhinotracheitis 'Swollen Head Syndrome'
A Pocket Guide to
By Paul McMullin
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A viral disease of chickens, turkeys (see separate summary), guinea fowl and possibly pheasants seen in Europe, Africa, South America and North America. It is caused by a pneumovirus of the Paramyxoviridae family, first isolated from poults in South Africa in 1978. Two subgroups have been identified on the basis of the G-protein sequence: A (original UK isolates) and B (original southern Europe isolates). There is rapid lateral transmission with infection by aerosol through the respiratory route; vertical transmission is uncertain. As for many infections, fomites can be important in moving infection between farms. The incubation period is 5-7 days, morbidity is 10-100% and mortality can be 1-10%.
- Decreased appetite, weight gain and feed efficiency.
- Facial and head swelling (though this can occur in other conditions).
- Loss of voice.
- Ocular and nasal discharge.
- Serous rhinitis and tracheitis, sometimes pus in bronchi. If secondary invasion by E. coli then pneumonia, airsacculitis and perihepatitis.
- Congestion, oedema and pus in the air space of the skull occurs in a proportion of affected birds due to secondary bacterial infections.
Clinical signs, serology, isolation of ciliostatic agent. Differentiate from Infectious Bronchitis, Lentogenic Newcastle disease, low virulence avian influenza, Ornithobacterium rhinotracheale. Serology - Elisa normally used, not all commercial kits are equally sensitive to response to both A and B challenge viruses.
Antibiotic not very effective. Control respiratory stressors, chlorination of drinking water, multivitamins.
All-in/all-out production, vaccination (degree of cross protection between A and B types remains to be established). Live vaccines can reduce clinical signs and adverse effects, inactivated vaccines may be used in breeders prior to lay.
|Figure 10. Pus in skull bones. This is a common sequel to avian pneumovirus infection in both chickens and turkeys.|