[Epizootiology of fowls adenoviruses]

Fowl adenoviruses of the serotype 4 from Germany were characterised by restriction enzyme analysis in comparison to isolates from Asia, South America and the FAV4 reference strain KR5. Only strain Da60 which was isolated from a psittacine aviary was identical with the reference strain KR5. None of the isolates was identical with the highly pathogenic strains from India and Ecuador. One-day-old chicks were infected orally and intramuscularly with the reference strain KR5, the psittacine isolate Da60 and isolate K1013 from Ecuador. Whereas no mortality was seen with the two strains KR5 and Da60, the mortality with K1013 was 100%. The main pathological signs were a swollen liver with necrosis and a lymphocyte depletion with a loss of the follicle structure. To investigate a second subject of avian adenovirus epizootiology several FAVs were characterized serologically and with PCR which was combined with the digestion of the PCR products. Including the reference strains, both methods were compared. It was shown that the digestion of the PCR products allows a clear attribution to a specific serotype, which underlines the usefulness of this method for diagnostic purposes.