Genotype Distribution and Phylogenetic Analysis of Rotaviruses in Thailand and Emergence of Uncommon Genotypes

Rotavirus remains a major cause of diarrhea in infants and young children especially in developing countries. Monitoring changes in rotavirus strains is necessary to assess the potential effectiveness of vaccines in specific geographic locations. This project aimed at monitoring the epidemiological status of rotavirus among Thai children. A total of 73 positive fecal samples for rotavirus were collected from hospitalized infants and children with acute gastroenteritis or diarrhea between 2012 and 2014 and analyzed for Gand P-genotypes by semi-nested multiplex PCR or DNA sequencing. The most prevalent genotype was G1P[8] (61.64%) followed by G8P[8] (21.92%), G2P[4] (8.22%), G3P[8] (4.11%), G9P[8] (2.74%), and G2P[8] (1.37%), Interestingly, the unusual genotypes, G8P[8] and G2P[8] were identified in this study. A phylogenetic analysis of VP7 and VP4 genes of strains detected in the present study revealed that G1 belonged to G1-Ic, and G1-IIc ; G2 belonged to G2-IIa; G3 belonged to G3-Ia; G8 belonged to G8-I; and G9 belonged to G9III lineages, while P[4] and P[8] were identified as P[4]-Vb and P[8]-III lineages, respectively. The distribution of unusual genotypes that possess neither VP7 nor VP4 specificity with the available rotavirus vaccine currently in use may represent a challenge to the outcome and success of vaccination.