Detection of infectious bursal disease viruses by using cloned cDNA probes.

A molecular clone representing 445 base pairs at the 3' end of infectious bursal disease virus (IBDV) genome segment B was used in a dot blot hybridization assay to detect viral RNA from cell culture and from chicken bursa and spleen tissue specimens. The cloned nucleotide sequence represents approximately 14% of the virus-encoded polymerase (VP-1) gene. The lower detection limit of radiolabeled probes prepared from this clone was 0.1 ng of IBDV double-stranded RNA. The probe had broad specificity and was used to detect four serotype 1 IBDV strains and one serotype 2 IBDV strain. This probe, however, did not cross-react with nucleic acid extracted from nine unrelated poultry viruses. A rapid procedure for isolation of IBDV genomic RNA from bursa and spleen tissue specimens was developed and used with the dot blot hybridization assay to detect IBDV strains in tissue samples from experimentally infected and commercially reared chickens.