One-year molecular survey of astrovirus infection in turkeys in Poland

The presence of turkey astrovirus (TAstV) was monitored in meat-type turkey flocks in Poland in 2008. Clinical samples (10 individual faecal swabs/flock) from 77 flocks aged 1-19 weeks were collected from different regions of the country. RT-PCR experiments were performed for detection and molecular characterization of TAstV using four sets of primers within the RdRp gene (ORF1b). The prevalence of astrovirus was 34/77 (44.15%) in the flocks tested. TAstV type 2 was associated with 30 of 77 infections (38.9%), either alone or in mixed infections; TAstV type 1 was detected in 9 of 77 flocks (11.6%), either alone or in mixed infections; ANV was detected only in one flock (1.29%) by sequence analysis during this study. Phylogenetic analysis revealed genetic variability in the TAstV strains that were isolated. Some of Polish TAstV-2 strains were genetically related to the North American isolates; however, most of them formed a distinct subgroup of "European" isolates, suggesting their separate origin or evolution. Additionally, due to the high variability of the TAstV sequences, the most suitable method for TAstV typing seems to be sequencing.