Prevalence of group C rotaviruses in weaning and post-weaning pigs with enteritis

Diarrheic fecal specimens collected from porcine herds were screened for the presence of group C rotaviruses using a reverse transcription-polymerase chain reaction (RT-PCR) assay. A total of 188 samples were tested and 54 were positive. When compiled these data with diagnostic results on group A rotaviruses and enteric caliciviruses we found that all but 5 group C rotavirus positive samples contained at least one additional virus. A subset of samples were subjected to nucleotide sequencing. The selected strains showed an unexpectedly wide range of nucleotide sequence heterogeneity (88.6-100%) to each other and to the reference porcine group C rotavirus strain, Cowden. The nucleotide sequence identity to the genuine bovine and human strains were, respectively, 86.8 and 87.2% or less. In conclusion, our study demonstrates that infection with group C rotavirus is frequent in Italian piggeries. The considerable rate of multiple infections requires further studies to investigate the pathogenic potential of group C rotaviruses in pigs, alone or in mixed infection, and raises challenges in the laboratory diagnosis of porcine enteric infections.