Emergence and evolution of highly pathogenic porcine epidemic diarrhea virus by natural recombination of a low pathogenic vaccine isolate and a highly pathogenic strain in the spike gene.

高致病性猪流行性腹泻病毒的出现和进化，是由于低致病性疫苗分离株与高致病性毒株在刺突基因中的自然重组所致