Extended analyses of rotavirus C (RVC) G-types and P-types reveal new cut-off value for the G-types and reclassification of strains

ABSTRACT Rotavirus C (RVC) is an important cause of gastroenteritis in humans and pigs and has also been detected in cattle, ferrets, minks, and dogs. Incidental zoonotic transmissions have been described. In contrast to rotavirus A (RVA), a complete genotyping system for RVC has not yet been established due to limited or incomplete sequence data. In this study, 138 complete nucleotide sequences for VP7 (G-type) and 97 complete nucleotide sequences for VP4 (P-type) of porcine RVC-positive samples have successfully been generated and genotyped. Together with available sequences from the NCBI database, phylogenetic analyses were conducted, cut-off values were re-evaluated, and the current classification system was adapted. Pairwise identity frequency analyses revealed a new cut-off value of 82% instead of the previous 85% for the G-type and confirmed the current cut-off value of 85% for the P-type. This resulted in the identification of 21 G-types and 39 P-types, including 4 new G-types and 10 new P-types. The results of the investigations expand the existing knowledge about the genetics of RVC and demonstrate the enormous diversity of porcine RVC sequences in particular. IMPORTANCE This article provides a new sequence data set of porcine rotavirus C (RVC) strains. The extended full-length analysis of RVC G-types and P-types enabled us to review the current classification system. According to the guidelines of the rotavirus classification working group (RCWG), the results led to a new cut-off value of RVC G-types and required the reclassification of numerous RVC G-types. In addition, several new genotypes have been found. The present work closes the aforementioned knowledge gap and provides important, comprehensive data for RVC genetic diversity.