The third strain was discovered in a Minnesota hog herd. Douglas Marthaler, an assistant professor of veterinary population medicine at the Univ. of Minnesota, reported the research findings to the CDC's Emerging and Infectious Diseases Journal. He wrote that the new strain is at least as virulent as the original strain that emerged in 2013.
"Although the PEDV variant-INDEL strain [OH851] was first reported in February 2014 by the Ohio Department of Agriculture, the PEDV variant-INDEL strains were first detected in June 2013, which suggests that the original PEDV strain mutated or that two different PEDV strains were introduced concurrently into the United States," Marthaler noted
So far, there are three naturally occurring PEDv strains in the US: the original virus; a second less-virulent PEDv strain that previously had been identified; and the third strain that Marthaler reported.
"Documenting PEDV variation is vital to understanding the natural evolution of the virus and possibly identifying portions of the genome associated with different clinical disease features," the report said.
"The most compelling need is to understand how exposure by sows to different PEDV strains correlates with protection of piglets from clinical disease. Whether the PEDV S2aa-del strain will circulate in the North American swine population is not known," the report concluded.