AND CHICKEN INFECTIOUS ANAEMIA VIRUS INFECTIONS IN HUNGARY

SUMMARY In the mid-seventies and early eighties several outbreaks of infectious bursal disease (IBD) were recorded in 8-21-day-old chickens. High morbidity (80%), low mortality (2-4%) and rapid recovery were characteristic features of the outbreaks. Infectious bursal disease virus (IBDV) was identified by virus isolation, serological tests, transmission electron microscopy, immunofluorescence assay and experimental infection of chickens. Serological surveys indicated that IBDV was widespread in Hungary which was successfully controlled by classical serotype 1 vaccines. In the early nineties several outbreaks, typical of the very virulent IBDV (vvIBDV) were reported in 4-6-week-old broilers. Nucleotide sequencing of the VP2 gene variable domain of IBDVs from these cases indicates that vvIBDV is present in Hungary which is poorly protected against by common vaccination schemes with classical serotype 1 vaccines. Therefore new vaccination strategies have been implemented with various success. In the early nineties during the investigation of stunting/runting disease syndrome, chicken infectious anaemia virus (CAV) was isolated from young broiler chickens. Serological surveys proved that CAV is widespread in the Hungarian chicken population, but vaccination against CAV is not a routine practice. Mouse monoclonal antibody (mAb) has been developed against VP3 of CAV, which is successfully used for the detection of CAV