Rapid differentiation of vaccine strain and Chinese field strains of transmissible gastroenteritis virus by restriction fragment length polymorphism of the N gene

Abstract

A strain of transmissible gastroenteritis virus (TGEV), designated H16, was isolated in PK-15 cells and passaged serially to level 165. Vaccines based on passages 155-165 in cell cultures are available commercially as vaccines for the prevention and control of infections with TGEV in China. Nucleoprotein (N) sequences of the virus at passages 155 and 165 were aligned and compared using a computer software program. The suitability of restriction fragment length polymorphism (RFLP) analysis for differentiation of the vaccine strain from the other TGEVs was investigated. The RFLP analysis identified a change in the cleavage sites of AclI at passages 155 and 165. This RFLP pattern of the N gene differentiated the Chinese vaccine strain from its parental strain, the 11 TGEVs studied and the other reported TGEVs in the GenBank. Using phylogenetic analysis, the Chinese TGEVs were divided into three groups (G1, G2, and G3). The G3 Chinese TGEVs possessed several specific nucleotides and amino acids that were not found in the G1 and G2 Chinese TGEVs or the other reference TGEVs. Analysis of the phylogenetic trees revealed that the G3 TGEVs represent a separate group that is distinct from the non-Chinese TGEVs and from Chinese TGEVs isolated previously. These findings suggest that Chinese strains of TGEV are evolving continuously.

Detection and Molecular Diversity of Spike Gene of Porcine Epidemic Diarrhea Virus in China

“…The results indicated that PEDV has a high prevalence rate in pig herds. TGEV was also detected by RT-PCR [16] in our lab, and the overall detection rate was 29.12% in clinical samples. Two other research groups in China reported that 40.8% (20 of 49) and 22.73% (5 of 22) sow milk samples were positive for PEDV in 2011 [5,6], and hypothesized that sow milk could represent a possible route for the vertical transmission of PEDV from sow to suckling piglets [5].…”

Reverse Transcription Loop-Mediated Isothermal Amplification for Rapid Detection of Transmissible Gastroenteritis Virus

“…Establishment of rapid, sensitive, and cost-effective diagnostic assays for detecting TGEV is highly desirable. In addition to conventional virus isolation, there are other diagnostic methods available for TGEV, for example, Multiplex PCR and multiplex RT-PCR, real-time RT-PCR, restriction fragment length polymorphism, microarray hybridization assay, and blocking ELISA [8,21,28,36,40]. Although these methods are effective, they may require either high-precision instruments or complicated procedures.…”

Sporadic re-emergence of enzootic porcine transmissible gastroenteritis in Hungary

“…However, occasional reports of TGEV-specific seropositivity (Elvander et al, 2000;Brendtsson et al, 2006;Roic et al, 2012) and even sporadic outbreaks in different parts of the world (Pritchard et al, 1999;Kim et al, 2000;Miyazaki et al, 2010;Wang et al, 2010) indicate that TGE cannot be neglected, as the virus is still present in pig herds, although mostly without clinical manifestations.…”