Whole genomic analysis of human and bovine G8P[1] rotavirus strains isolated in Nigeria provides evidence for direct bovine-to-human interspecies transmission.

Bovine group A rotavirus (RVA) G8P[1] strains have been rarely detected in humans. Two Nigerian G8P[1] strains, HMG035 (RVA/Human-tc/NGA/HMG035/1999/G8P[1]) and NGRBg8 (RVA/Cow-tc/NGA/NGRBg8/1998/G8P[1]), were previously suggested to have the VP7, VP4, and NSP1 genes of bovine origin. In order to obtain precise information on the origin and evolution of these G8P[1] strains, the complete nucleotide sequences of the whole genomes of strains HMG035 and NGRBg8 were determined and analyzed in the present study. On whole genomic analysis, strains HMG035 and NGRBg8 were found to be very closely related to each other in all the 11 segments, and were found to have a bovine RVA-like genotype constellation (G8-P[1]-I2-R2-C2-M2-A11-N2-T6-E2-H3). Furthermore, on phylogenetic analysis, each of the 11 genes of strains HMG035 and NGRBg8 appeared to be of bovine origin. Thus, strains HMG035 and NGRBg8 were suggested to be derived from a common origin, and strain NGRBg8 was assumed to represent an example of bovine RVA strains that were transmitted to humans. Our findings provide clear evidence for direct bovine-to-human interspecies transmission of RVA strains.