Evolutionary analysis of all eleven genes of species C rotaviruses circulating in humans and domestic animals.

Species C rotaviruses (RVC) are the second most common rotavirus species known to cause gastroenteritis in humans and pigs and with occurrence documented in cattle, dogs, ferrets, and sloth bears. Despite the host-specific nature of RVC genotypes, cross-species transmission, reassortment, and recombination events are also documented. In the present study, we inferred the evolutionary history of globally circulating RVC strains, including time scale stasis, the most probable ancestral country, and the most probable source host using Bayesian methods implemented in BEAST v.1.8.4. The human-derived RVC strains were majorly monophyletic and further grouped into two lineages. The RVC strains derived from pigs were monophyletic for the VP1 and the remaining genes were classified into 2 to 4 groups based on the high posterior support. The root mean age for all the genes indicated the circulation of RVC for over 800 years. Overall, the time to Most Recent Common Ancestor of human RVC strains dated back to the beginning of the 20th century. The VP7 and NSP2 genes had the lowest rates of evolution compared to other genes. The majority of the genes of RVC showed their origin in Japan except for VP7 and VP4 genes in South Korea. The phylogeographic analysis with the country as a trait showed the role of Japan, China, and India in the dispersion of the virus. In the current study, significant transmission links between different hosts were analyzed for the first time using the host as a trait. Significant transmission links between pigs and other animal species as well as humans indicate possible transmission from the pig as a source host and suggest monitoring of proximity with animals.

Rotavirus C infections in asymptomatic piglets in India, 2009-2013: genotyping and phylogenetic analysis of all genomic segments.

Asymptomatic infection with rotavirus C (RVC) was observed in pigs in India, with a detection rate of 20%. Sequencing of the VP6, VP7, and NSP4 genes of RVC strains identified the genotypes I7/I10, G1, and E5, respectively. Full genome sequencing of one of these strains revealed that the genotypes of the VP4, VP1, VP2, VP3, NSP1, NSP2, NSP3, and NSP5 genes were P1, R1, C1, M3, A1, N5, T5, and H1, respectively. The detection of porcine RVC strains at two different locations in India at different time points strongly suggests that they are circulating continuously in the pig population through asymptomatic infections.