Whole genome analysis provides evidence for porcine-to-simian interspecies transmission of rotavirus-A.

We report here whole genome analysis of a porcine rotavirus-A (RVA) strain RVA/Pig-wt/KNA/ET8B/2015/G5P[13] detected in a diarrheic piglet, and nearly whole genome (except for VP4 gene) analysis of a simian RVA strain RVA/Simian-wt/KNA/08979/2015/G5P[X] detected in a non-diarrheic African green monkey (AGM) on the island of St. Kitts, Caribbean region. Strain ET8B exhibited a G5-P[13]-I5-R1-C1-M1-A8-N1-T7-E1-H1 genotype constellation that was identical to those of Brazilian porcine RVA G5P[13] strains RVA/Pig-wt/BRA/ROTA01/2013/G5P[13] and RVA/Pig-wt/BRA/ROTA07/2013/G5P[13], the only porcine G5P[13] RVAs that have been analyzed for the whole genome so far. Phylogenetically, all the 11 gene segments of ET8B were closely related to those of porcine and porcine-like human RVAs within the respective genotypes. Although the porcine G5P[13] RVAs exhibited identical genotype constellations, ET8B did not appear to share common evolutionary pathways with the Brazilian porcine G5P[13] RVAs. Interestingly, the VP2, VP3, VP6, VP7, and NSP1-NSP5 genes of simian RVA strain 08979 were closely related to those of porcine and porcine-like human RVA strains, exhibiting 99%-100% nucleotide sequence identities to cognate genes of co-circulating porcine RVA strain ET8B. On the other hand, the VP1 of 08979 appeared to be genetically divergent from porcine and human RVAs within the R1 genotype, and its exact origin could not be ascertained. Taken together, these observations suggested that simian strain 08979 might have been derived from interspecies transmission events involving transmission of ET8B-like RVAs from pigs to AGMs. In St. Kitts, AGMs often stray from the wild into livestock farms. Therefore, it may be possible that the AGM acquired the infection from a pig farm on the island. To our knowledge, this is the first report on detection of porcine-like RVAs in monkeys. Also, the present study is the first to report whole genomic analysis of a porcine RVA strain from the Caribbean region.