Porcine epidemic diarrhea virus

It was first discovered in Europe, but has become increasingly problematic in Asian countries, such as Korea, China, Japan, the Philippines, and Thailand. It has also spread to North America: it was discovered in the United States on May 5, 2013 in Indiana, and in Canada in the winter of 2014. In January 2014, a new variant strain of PEDV with three deletions, one insertion, and several mutations in S (spike) 1 region was identified in Ohio by the Animal Disease Diagnostic Lab of Ohio Department of Agriculture.

PEDV has a substantial economic burden given that it is highly infectious, resulting in significant morbidity and mortality in piglets. Morbidity and mortality rates were lower for vaccinated herds than for nonvaccinated herds, which suggests the emergence of a new PEDV field strain(s) for which the current vaccine, based on the CV777 strain, was partially protective. Consumers are likely to feel the effects of the viral disease in the form of higher prices for pork products.

Evolution

A Bayesian study of 138 genomes showed that the virus has six subtypes. Groups 1 and 2 originated in North America and groups 3–5 originated in Asia. The evolution rate of the genome was estimated to be 3.38 × 10⁻⁴ substitutions/site/year similar to other RNA viruses. The most recent common ancestor of the extant strains evolved ~1943.