Determination of shedding profiles of infectious bursal disease virus in faeces of infected SPF chickens using qRT-PCR and association with levels in host tissues, dust and litter

Australian endemic serotype 1 variant 02/95 and classical 06/95 strains of IBDV were detected in thymus, bursa, caecal tonsils and spleen of maternal a.ntibody free SPF chickens inoculated orally at day 1 of age. High levels of virus from both strains were detected at 7 dpi and lower levels at 14 and 28 dpi. Faecal shedding of both strains was detected from 2 dpi and reached a maximum at 5 dpi followed by a gradual reduction. SPF chickens inoculated with both IBDV strains showed bursal atrophy but atrophy was not significantly different between 2 strains. Sera collected at 7, 13, 21 and 28 dpi indicated active infection. Antibody titre increased from 7 dpi onwards, reaching maximal at 21 dpi. Both IBDV strains were detected in environmental samples: poultry dust and bedding materials. This study reveals that the IBDV 02/95 and 06/95 strains behave similarly in host chickens and that qRT-PCR monitoring of IBDV in environmental samples such as poultry dust or litter is feasible.