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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #70702
Title: DEVELOPMENT OF PCR-BASED TECHNIQUES TO IDENTIFY PORCINE TRANSMISSIBLE GASTROENTERITIS CORONAVIRUS ISOLATES

Author
item Woods, Roger

Submitted to: Canadian Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Transmissible gastroenteritis is still an economically important disease in U.S.swine herds. The disease produces illness and death losses in young piglet and export markets are closed to breeding stock from transmissible gastroenteritis virus (TGEV) positive herds. Molecular techniques were developed to rapidly identify the TGE virus and differentiate it from other viruses. The techniques developed are important aids to diagnostic laboratories and university researchers as a first step in generating a control plan for TGEV disease outbreaks and tracking the spread of the virus. The findings may be used in the development of in vitro techniques to identify virulent and attenuated strains of TGEV. These are the first methods that allow individual enteric coronaviruses to be identified at the strain level.

Technical Abstract: Sixteen isolates of transmissible gastroenteritis virus (TGEV) and one isolate of porcine respiratory coronavirus were characterized using RT-PCR amplification of four antigenic subsites in the site A epitope on the TGEV spike gene. The PCR products were digested with restriction enzymes Sau3aI and SspI and the sizes of the fragments were determined. Three different restriction pattern were observed with each enzyme. The recognition site for Sau3aI was missing in one isolate, was present in 13 isolates and three isolates had two sites. PCR-products with a single site had three different fragment sizes and the other isolates produced two fragments with different sizes. The SspI recognition site was not present in five isolates and 12 isolates had a single site that produced two fragments of different sizes. Based on the restriction fragment sizes, the 17 isolates were separated into seven groups. Direct sequencing of the 425 bp nested set fragments demonstrated greater than 96% sequence homology among the 16 isolates and 100% homology in the four antigenic subsites in the conserved site A epitope. The groups are discussed in relation to their sequence homology and virulence. In vitro procedures have been developed to identify several porcine enteric coronavirus isolates at the strain level.