Full genomic analyses of two human G2P[4] rotavirus strains detected in 2005: identification of a caprine-like VP3 gene.

Although G2P[4] rotaviruses are common causes of infantile diarrhoea, to date only the full genomes of the prototype (strain DS-1) and another old strain, TB-Chen, have been analysed. We report here the full genomic analyses of two Bangladeshi G2P[4] strains, MMC6 and MMC88, detected in 2005. Both the strains exhibited a DS-1-like genotype constellation. Excluding the VP4 and VP7 genes, and except for VP3 of MMC88, the MMC strains were genetically more closely related to the contemporary G2P[4] and several non-G2P[4] human strains than the prototype G2P[4] strain. However, by phylogenetic analyses, the VP2, VP3 (except MMC88), NSP1 and NSP3-5 genes of these strains appeared to share a common origin with those of the prototype strain, whilst their VP1, VP6 and NSP2 genes clustered near a caprine strain. The VP3 gene of MMC88 exhibited maximum relatedness to a local caprine strain, representing the first reported human G2P[4] strain with a gene of animal origin.