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A total of 1442 live birds and 73 dead birds out of 215 bird collections in Spain, Germany, Italy, the UK and Denmark were tested for avian bornavirus (ABV) infection by four different methods. The majority of the birds were psittacines belonging to 54 different genera of the order Psittaciformes. In total, 22.8% of the birds reacted positive for ABV in at least one of the tests. Combined testing of swabs from the crop and cloaca, and serum for the diagnosis of ABV infection in live birds revealed that virus shedding and antibody production coincided in only one-fifth of the positive birds so that the examination of these three samples is recommended for reliable ABV diagnosis. By statistical analysis of this large number of samples, the ABV infection proved to be highly significant (P

Two Muscovy duck reoviruses, strains y1/79 and 1625/87, were investigated with regard to their genome organization, polypeptide pattern, serotype specificity, and pathogenicity. Electrophoretic analysis of the genome revealed the migration pattern of avian reoviruses. In spite of general conformity, great polymorphism was detected in the electrophoretic mobility of individual genome segments of the two strains sharing only three segments of identical size (L1, M2, M3). Only one segment (M3) migrated into the same position as the corresponding segment of prototype chicken reovirus S1133. The basic electrophoretic mobility pattern of the immunoprecipitated polypeptides, eight structural and two non-structural, closely resembled that of the chicken reovirus. However, considerable strain-specific variation was also seen at the protein level, with the sigma(c) polypeptides exhibiting the most obvious migration differences. Based on the results of cross-neutralization assays the two Muscovy duck reovirus strains were grouped into one serotype, with no cross-reactivity to the chicken serotype S1133. In experimental infections, despite virus replication proved by faecal virus excretion and antibody response, only strain y1/79 was pathogenic for 16-day-old Muscovy ducklings, thus making strain 1625/87 a possible candidate as vaccine strain.

Summary EDS virus strain 127 did not induce clinical signs or gross lesions in susceptible chicks of various age groups and in adult cocks. Virus persistence in various internal organs and the rate of excretion of virus by experimentally‐infected chicken declined rapidly with increasing age. Virus 127 was detectable in organs of young chicks up to 5 weeks post‐infection and in their faeces up to 2 weeks post‐infection. In adult birds virus 127 persisted in tissues for about 3 weeks and was excreted with faeces for only 1 week post‐infection. Vaccination of adult cocks with an inactivated vaccine resulted in intermittent shedding of virus only within the first 4 days post‐challenge; thus, in comparison to non‐vaccinated chickens, vaccination reduced virus excretion in faeces to a major extent.