New research published in the American Academy of Microbiology’s journal mBio has used genomic sequences of three emergent strains of porcine epidemic diarrhea virus (PEDV) to determine the origin, evolution, and genotypes of a recent outbreak of the virus in the United States.
The sudden emergence and rapid spread of PEDV, a coronavirus, for the first time in the United States has caused significant economic and public health concerns. Ongoing outbreaks of the Middle East respiratory syndrome coronavirus in humans from countries in or near the Arabian Peninsula and the historical deadly nature of the 2002 outbreaks of severe acute respiratory syndrome coronavirus have created further anxiety over the emergence of PEDV in the United States due to the lack of scientific information about the origin and evolution of this emerging coronavirus.
The researchers characterised histological lesions in small intestine sections of affected pigs and the complete genomic sequences of three emergent strains of PEDV isolated from outbreaks in Minnesota and. Genetic and phylogenetic analyses of the three U.S. strains revealed a close relationship with Chinese PEDV strains and their likely Chinese origin. The U.S. PEDV strains underwent evolutionary divergence, which can be classified into two sublineages. The three emergent U.S. strains are most closely related to a strain isolated in 2012 from Anhui Province in China, which might be the result of multiple recombination events between different genetic lineages or sublineages of PEDV. Molecular clock analysis of the divergent time based on the complete genomic sequences is consistent with the actual time difference, approximately 2 to 3 years, of the PED outbreaks between China (December 2010) and the United States (May 2013). The finding that the emergent U.S. PEDV strains share unique genetic features at the 5′-untranslated region with a bat coronavirus provided further support of the evolutionary origin of PEDV from bats and potential cross-species transmission. The data from this study have important implications for understanding the ongoing PEDV outbreaks in the United States and will guide future efforts to develop effective preventive and control measures against PEDV.
Journal reference: Huang YW, Dickerman AW, Piñeyro P, Li L, Fang L, Kiehne R, Opriessnig T, Meng XJ. 2013. Origin, evolution, and genotyping of emergent porcine epidemic diarrhea virus strains in the United States. mBio 4(5):00737-13. doi:10.1128/mBio.00737-13.
Story source: Adapted from the paper’s abstract under the terms of the Creative Commons Attribution-Noncommercial-ShareAlike 3.0 Unported license