Molecular epidemiology of Rotavirus A, causing acute gastroenteritis hospitalizations among children in Nha Trang, Vietnam, 2007-2008: Identification of rare G9P[19] and G10P[14] strains.

Rotavirus A (RVA) causes acute diarrhea in children as well as animals. As part of a cross-sectional study of children less than 5 years of age hospitalized for acute diarrhea in Vietnam during a 15-month period (2007-2008), 322 (43.5%) of 741 fecal specimens contained RVA with 92% either G1P[8] or G3P[8]. This study was undertaken to further characterize strains that remained untypeable to complete the G and P genotypes of the 322 rotavirus-positive specimens. While 307 (95.3%) strains possessed the common human RVA genotypes: G1P[8] (45.0%), G2P[4] (2.8%), G3P[8] (46.9%), and G9P[8] (0.6%), sequencing of initially untypeable specimens revealed the presence of two unusual strains designated NT0073 and NT0082 possessing G9P[19] and G10P[14], respectively. The genotype constellation of NT0073 (G9-P[19]-I5-R1-C1-M1-A8-N1-T7-E1-H1) and the phylogenetic trees suggested its origin as a porcine RVA strain causing diarrhea in a 24-month-old girl whereas the genotype constellation of NT0082 (G10-P[14]-I2-R2-C2-M2-A3-N2-T6-E2-H3) and the phylogenetic trees suggested its origin as an RVA strain of artiodactyl origin (such as cattle, sheep and goats) causing diarrhea in a 13-month-old boy. This study showed that RVA strains of animal host origin were not necessarily attenuated in humans. A hypothesis may be postulated that P[19] and P[14] VP4 spike proteins helped the virus to replicate in the human intestine but that efficient onward human-to-human spread after crossing the host species barrier may require the virus to obtain some additional features as there was no evidence of widespread transmission with the limited sampling performed over the study period. J. Med. Virol. 89:621-631, 2017.