Molecular characterization of unusual G10P genomic constellations and evidence of zooanthroponosis in bovines

Group A rotaviruses (RVA) are a major cause of diarrhea in neonatal calves and children. The present study examined G/P combinations and genetic characteristics of RVAs in diarrheic bovine calves in Western India. RVAs were detected in 27 samples (17.64%) with predominance of G10P[11] (51.85%), followed by previously unreported genomic constellations, G6P[14] (14.81%), and, G6P[4] (7.40%) and G10P[33] (3.70%). Sequencing and phylogenetic analysis revealed circulation of G10 (Lineage-5), G6 (Lineage-2), P[11] (Lineage-3), P[14] (proposed Lineage-8) and P[4] (Lineage-3) genotypes. The predominant G10P[11] strains were typical bovine strains and exhibited genotypic homogeneity. The rare, G10P[33] strain, had VP7 and VP4 genes of bovine origin but resemblance of VP6 gene with simian strain indicated possible reassortment between bovine and simian (SA11-like) strains. The VP6 and VP7 genes of other two rare strains, G6P[14] and G6P[4], were similar to those of bovine stains, but the VP4 was closely related to those of the human-bovine like and human strains, respectively. Additionally, in VP4 gene phylogenetic tree Indian P[14] strains constituted a closely related genetic cluster distinct from the other P[14] strains, hence Lineage-8 was proposed for them. These findings indicated that bovines could serve as source for anthropozoonotic transmission of G6P[14] strains while zooanthroponotic transmission followed by reassortment with human strain gave rise to G6P[4] strains. The observations of present study reinforce the potential of rotaviruses to cross the host-species barrier and undergo reassortant to increase genetic diversity which necessitates their continuous surveillance for development and optimization of prevention strategies against zoonotic RVAs.