Investigation of avian rotavirus infections in broiler chicks from commercial flocks with different performance efficiency indexes.

The aim of this study was to investigate and compare the frequency of occurrence of avian rotavirus (AvRV) in poultry flocks according to its Performance Efficiency Index (PEI) scores. A total of 256 individual intestinal content samples of small sized-chicks (runts) with clinical signs of Runting Stunting Syndrome (RSS) and 24 clinically healthy chicks (control) were collected from twelve flocks in southern Brazil with different PEI scores: good (n = 4, PEI mean = 365); moderate (n = 4, PEI mean = 342) or poor (n = 4, PEI mean = 319). Silver-stained polyacrylamide gel electrophoresis (ss-PAGE) was used to detect and identify the AvRV species followed by RT-PCR and sequencing of the partial VP6 gene for species confirmation. AvRV was detected in 83% (10/12) of the flocks and 23.4% (60/256) of the chicks. The electrophoretic migration patterns of viral dsRNA segments were compatible with AvRV species A (AvRV- A), D (AvRV-D) and F (AvRV-F) in 9 (15%), 18 (30%), and 33 (55%) of the positive chicks fecal samples, respectively. The AvRV species identified by ss-PAGE were confirmed by RT-PCR and partial sequence analysis of the VP6 gene. The AvRV detection rate was statistically higher (p = 0.007) in chicks from flocks with poor PEI when compared to those with good PEI. The occurrence of AvRV-D and AvRV-F was statistically higher in 7 to 9 days old chicks, while AvRV-A was detected only in 13 to 14 days old animals.

Electrophoretic RNA genomic profiles of Brazilian Picobirnavirus (PBV) strains and molecular characterization of a PBV isolated from diarrheic calf.

Picobirnavirus (PBV) belongs to the family Picobirnaviridae. PBV are a group of emerging non-enveloped viruses, with a bisegmented double-stranded RNA genome that can infect a wide range of hosts. This study reports the occurrence of PBV in fecal samples from five Brazilian dairy cattle herds. From the 289 stool samples of individual calves analyzed by silver-stained polyacrylamide gel electrophoresis (ss-PAGE) the PBV was detected in 8.3 % (24/289), of which 10.2% (18/176) had diarrheic consistency. Of the 24 positive samples in ss-PAGE, 5 (20.8%) of them showed a small electrophoretic profile and 19 (79.2%) samples had large profile. From the 24 positives samples by ss-PAGE, 15 (62.5%) were successfully amplified (201 bp) using GI specific primers targeting the RdRp gene of PBV. The analysis of nucleotide identity matrix revealed that the bovine PBV strain identified in this study, showed the highest nucleotide identity (81%) with PBV strain detected in turkey (MD-2010/HM803965). This is the first nucleotide sequence of a bovine PBV strain in the American continent and the first detection of small genome profile of PBV-like strains in bovine hosts.