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Classification of Emergent U.S. Strains of Porcine Epidemic Diarrhea Virus by Phylogenetic Analysis of Nucleocapsid and ORF3 Genes

We read with particular attention the article “Isolation and Characterization of Porcine Epidemic Diarrhea Viruses Associated with the 2013 Disease Outbreak among Swine in the United States” by Chen and colleagues, published in January 2014 in the Journal of Clinical Microbiology. Chen et al. proposed that the full-length spike (S) gene or the S1 portion of it is a suitable phylogenetic marker to reflect evolutionary relationships between emergent U.S. and Chinese strains of porcine epidemic diarrhea viruses (PEDVs). This viewpoint proposed by the authors deserves more discussion.