Unusual outbreak of post-weaning porcine diarrhea caused by single and mixed infections of rotavirus groups A, B, C, and H

• RVC post-weaning diarrhea outbreak in RVA, RVB and RVC single and mixed infections.
• Multiple rotavirus group-diarrhea outbreaks in pigs are more common than reported.
• Molecular characterization of VP6, VP7 and VP4 genes of RVA, RVB and RVC.
• RVA genotypes G5P[13] and G9P[23] identified in Brazilian diarrheic weaned pigs.
• Porcine RVB G14 strain identified in Brazilian diarrheic weaned pigs.

Rotaviruses (RVs) are a major cause of severe diarrhea in humans and animals. Five of the nine RV groups (RVA, RVB, RVC, RVE, and RVH) have been previously detected in pigs; however, in pig herds worldwide, most studies highlight diarrhea outbreaks caused by RVA. In the present study, we describe detection and characterization of RV groups A, B, C, and H in fecal samples from pigs with single and mixed infections during a post-weaning diarrhea outbreak. The outbreak occurred in a single pig herd routinely vaccinated with an inactivated commercial vaccine for neonatal diarrhea control that included the RVA OSU (G5P[7]) strain. RVC (78%) was the most prevalent group found in single (34%) and mixed (44%) infections, followed by RVA (46%), RVB (32%), and RVH (18%). Phylogenetic analysis of three RVA strains allowed the characterization of two distinct G/P genotypes represented by G5P[13] and G9P[23], different from G5P[7] found in vaccines. Regardless of the RV group, mixed infections (54%) were more prevalent than single infections. Detection of RVB or RVH was associated with the presence of other RV groups, suggesting a secondary action of these RV groups in the reported outbreak. The detection of RV groups B, C, and H in the same pig herd suggests that these RVs act as causative agents of diarrhea and should be included in the diagnostic tests of porcine enteric diseases. These data provide new epidemiological information on RV diversity that need to be addressed in future studies for a better understanding and prevention of RV infections.