The epidemiology and genetic diversity of transmissible gastroenteritis virus (TGEV) in the United States (US) was investigated by testing clinical cases for TGEV by real time RT-PCR between January 2008 and November 2016. Prevalence of TGEV ranged between 3.8–6.8% and peaked during cold months until March 2013, in which prevalence decreased to < 0.1%. Nineteen complete TGEV genomes and a single strain of porcine respiratory coronavirus (PRCV) from the US were generated and compared to historical strains to investigate the evolution of these endemic coronaviruses. Sixteen of our TGEV strains share 8 unique deletions and 119 distinct amino acid changes, which might greatly affect the biological characteristics of the variant TGEV, and resulted in a “variant” genotype of TGEV. The “variant” genotype shared similar unique deletions and amino acid changes with the recent PRCV strain identified in this study, suggesting a recombination event occurred between the ‘‘variant’’ TGEV and PRCV. Moreover, the results indicate the “variant” genotype is the dominant genotype circulating in the US. Therefore, this study provides insight into the occurrence, origin, genetic characteristics, and evolution of TGEV and PRCV circulating in the US.
Bibliographical noteFunding Information:
The study was funded by the MNVDL. The authors thank the faculty and personal at the University of Minnesota Veterinary Diagnostic Laboratory (MNVDL) for their technical services. Fangzhou Chen was supported by China Agriculture Research System (No. CARS-36) and China Scholarship Council No. 201606760012 and was a visiting scholar at the University of Minnesota College of Veterinary Medicine during the construction of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.
© 2019, The Author(s).