January 7, 2015

Third strain of PEDv identified in US

US researchers have identified a new strain of Porcine Epidemic Diarrhoea virus, or PEDv, a sign the virus will keep mutating as hog producers work to contain it, Fox News reports.

The new strain was detected in a Minnesota hog herd and found to be at least as virulent as an original strain that emerged in the US in early 2013, said Douglas Marthaler, assistant professor of veterinary population medicine at the University of Minnesota.

Writing in a journal from the US Centers for Disease Control and Prevention last month, Marthaler believes the strain is a mutation of the original. A second, less-virulent strain had previously been identified.

The original strain may have mutated in response to increased immunity in herds, Marthaler said. It is also the nature of viruses like PEDv to evolve as they replicate.

It is unknown whether the third strain exists outside of the Minnesota herd in which it was found, Marthaler said.

Researchers previously concluded that PEDv can spread from pig to pig by contact with manure contaminated with the virus. It can also be spread from farm to farm on vehicles.

"Whether or not exposure to one of the earlier strains provides protection against this strain, I don't think anybody knows the answer to that question," said Harry Snelson, a veterinarian who represents the American Association of Swine Veterinarians.

PEDv has killed at least eight million pigs, about 10% of the US hog population, since 2013. The resulting drop in pork supply was largely responsible for pushing prices to record highs.

It remains unknown how the virus, previously found in parts of Asia and Europe, came to the US.

As for the new strain, it could have existed in the country without being detected since early 2013 or it could be a more recent mutation, experts said.