An Emergence of Equine-Like G3P[8] Rotaviruses Associated with Acute Gastroenteritis in Hospitalized Children in Thailand, 2016 −2018

Abstract

Rotavirus A (RVA) is recognized as a major etiology responsible for the development of acute gastroenteritis in children worldwide. The purpose of the present study was to perform the molecular characterization of RVA. A total of 323 stool specimens collected from hospitalized children with acute gastroenteritis in Chiang Rai, Thailand, in 2016-2018 were identified for G- and P-genotypes through RT-PCR analysis. RVA was more prevalent in 2017-2018 (37.8%) than in 2016-2017 (23.2%). The seasonal peak of RVA occurred from March to April. G3P[8] was predominant in 2016-2017 (90.6%) and 2017-2018 (58.6%). Other genotypes including G1P[8], G8P[8], G9P[8], and mixed infections were also identified. G3P[8] strains clustered together in the same lineage with other novel human equine-like G3P[8] strains previously identified in multiple countries and presented a genotype 2 constellation (G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2). Several amino acid differences were observed in the antigenic epitopes of the VP7 and VP8* capsid proteins of the equine-like G3P[8] compared with those of the RVA vaccine strains. The homology modeling of the VP7 and VP8* capsid proteins of the equine-like G3P[8] strains evidently exhibited that these residue differences were present on the surface-exposed area of the capsid structure. The emergence of the equine-like G3P[8] strains in Thailand indicates the rapid spread of strains with human and animal gene segments. Continuous surveillance for RVA is essential to monitor genotypes and genetic diversity, which will provide useful information for selecting rotavirus strains to develop a safe and effective RVA vaccine that is efficacious against multiple genotypes and variants.