Molecular characterization and phylogenetic analysis of transmissible gastroenteritis virus HX strain isolated from China.

Xiaoliang Hu,Xin Yin,Nannan Li,Liandong Qu,Zhige Tian,Juanjuan Qu

doi:10.1186/s12917-015-0387-8

Abstract

BackgroundPorcine transmissible gastroenteritis virus (TGEV) is the major etiological agent of viral enteritis and severe diarrhea in suckling piglets. In China, TGEV has caused great economic losses, but its role in epidemic diarrhea is unclear. This study aims to reveal the etiological role of TGEV in piglet diarrhea via molecular characterization and phylogenetic analysis.ResultsA TGEV-HX strain was isolated from China, and its complete genome was amplified, cloned, and sequenced. Sequence analysis indicated that it was conserved in the 5′ and 3′-non-translated regions, and there were no insertions or deletions in nonstructural genes, such as ORF1a, ORF1b, ORF3a, ORF3b, and ORF7, as well as in genes encoding structural proteins, such as the envelope (E), membrane (M), and nucleoprotein (N) proteins. Furthermore, the phylogenetic analysis indicated that the TGEV-HX strain was more similar to the TGEV Purdue cluster than to the Miller cluster.ConclusionsThe present study described the isolation and genetic characterization of a TGEV-HX strain. The detailed analysis of the genetic variation of TGEVs in China provides essential information for further understanding the evolution of TGEVs.

Highlights

Porcine transmissible gastroenteritis virus (TGEV) is the major etiological agent of viral enteritis and severe diarrhea in suckling piglets
When observed by electron microscopy, the virus displayed a circular shape, and the surface projections were petal-shaped, with a diameter ranging from 100 to 150 nm, which is similar in size to known TGEVs (Figure 1D)
Complete genome sequence of the TGEV-HX strain The full-length genome sequence of the TGEV-HX strain was deduced by combining the sequences of 10 overlapping cDNA fragments

Summary

Introduction

Porcine transmissible gastroenteritis virus (TGEV) is the major etiological agent of viral enteritis and severe diarrhea in suckling piglets. Transmissible gastroenteritis virus (TGEV) is the etiological agent of transmissible gastroenteritis (TGE), and it can cause viral enteritis and severe diarrhea with high morbidity in pigs of all ages, as well as high mortality in suckling piglets [1]. It occurs at swine-raising farms and results in significant economic losses [2,3]. TGEV is an enveloped virus belonging to the Coronaviridae (CoV) family and the Nidovirales order It possesses a large 28.5-kb single-stranded, positive-sense RNA genome.

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