Novel G9 rotavirus strains co-circulate in children and pigs, Taiwan

Fang-Tzy Wu,Krisztián Bányai,Luke Tzu-Chi Liu,Baoming Jiang,Li-Min Huang,Yhu-Chering Huang,Ming-Hui Liao,Chao A Hsiung,Szilvia Marton

doi:10.1038/srep40731

Abstract

Molecular epidemiologic studies collecting information of the spatiotemporal distribution of rotavirus VP7 (G) and VP4 (P) genotypes have shown evidence for the increasing global importance of genotype G9 rotaviruses in humans and pigs. Sequence comparison of the VP7 gene of G9 strains identified different lineages to prevail in the respective host species although some of these lineages appear to be shared among heterologous hosts providing evidence of interspecies transmission events. The majority of these events indicates the pig-to-human spillover, although a reverse route of transmission cannot be excluded either. In this study, new variants of G9 rotaviruses were identified in two children with diarrhea and numerous pigs in Taiwan. Whole genome sequence and phylogenetic analyses of selected strains showed close genetic relationship among porcine and human strains suggesting zoonotic origin of Taiwanese human G9 strains detected in 2014–2015. Although the identified human G9P[19] and G9P[13] rotaviruses represented minority strains, the repeated detection of porcine-like rotavirus strains in Taiwanese children over time justifies the continuation of synchronized strain surveillance in humans and domestic animals.

Highlights

Rotavirus A (RVA) is the major cause of acute gastroenteritis in infants and young children worldwide
Our analysis provides strong evidence that majority of gene segments, including the backbone genes, in the newly identified human G9 strains can be deduced from porcine RVA strains that co-circulated with the human G9 RVAs in parts of Taiwan
The Taiwanese rotavirus strain surveillance network was initiated in 2004 and children aged under 5 years admitted to hospital with acute gastroenteritis (AGE) were enrolled from 3 sentinel hospitals

Summary

Introduction

Rotavirus A (RVA) is the major cause of acute gastroenteritis in infants and young children worldwide. In addition to the common human rotavirus genotypes, the Taiwanese rotavirus strain surveillance network has detected several unusual RVA strains (e.g. genotype P[6] and P[19] RVA strains related to porcine RVA strains) in the pre vaccine era. The majority of circulating human G9 strains is thought to have descended from a single sublineage around late 1980s following a putative interspecies transmission event between pigs and human in mid-1980s12 This newly emerging sublineage has been found to differ from other lineages that include the early human G9P[8] strains (such as WI61, F45, and G2275) and almost all porcine G9 strains, including the porcine-origin human G9P[19] strains (such as Mc323 and RMC321). Analysis of full genomic sequences determined for unusual porcine-like human G9 strains has raised the possibility of interspecies transmission events between the two host species by demonstrating shared genetic lineages of selected rotavirus genes. We demonstrate that many of these genes cluster in genetic lineages that are distinct from those described in other parts of the world, indicating a complex history of reassortment and spillover events between the two hosts in Taiwan

Methods

Results

Conclusion