Isolation and Identification of a New Strain of Porcine Transmissible Gastroenteritis Virus from Chongqing, Southwestern China

摘要

Porcine transmissible gastroenteritis virus (TGEV) infections continue to cause significant losses in the swine industry. The objective of the study was to document the isolation a new strain of TGEV, information which may also contribute significantly to understanding molecular epidemiology and evolution of TGEV in China. In this study, a suspected transmissible gastroenteritis virus (TGEV) strain was isolated from faeces of sick piglets in Chongqing (China) using swine testis (ST) cell lines. With the total RNA extracted from infected ST cells, the M gene of TGEV was amplified by polymerase chain reaction (PCR). The virus was named as the CQ strain, and was also identified by homology analysis, cell cytopathic effects (CPE), indirect fluorescent antibody test (IFA) and electron microscopy (EM). The results indicated that this virus was TGEV by a series of identification tests. The membrane proteins M gene was cloned and sequenced. Alignment with other 21 reference strains of TGEV and 1 strain PRCV in GenBank, showed that the homology was 94.3-99.6% for nucleotide sequence, 92.4-98.9% for amino sequence, respectively. The phylogenetic analysis has indicated that TGEV strains can be classified into two clusters, the CQ strain belonged to cluster I, and shared closest relationship with Purdue-P115.