U.S. losses from the porcine epidemic diarrhea virus that’s killed millions of pigs may wane by the end of the year as surviving sows pass on resistance to their piglets, the World Organisation for Animal Health said.
U.S. pigs’ initial lack of natural immunity to the virus explains the extent of the losses, according to Brian Evans, deputy director general of the Paris-based intergovernmental animal-health group, known by its French acronym OIE.
Porcine epidemic diarrhea virus has been confirmed in at least 29 U.S. states since it was first found in Iowa pigs a year ago, according to the U.S. Department of Agriculture. Rabobank has forecast U.S. pork output may fall as much as 7 percent this year on the outbreak. Lean hog futures traded in Chicago have jumped 47 percent this year as losses mounted.
"The devastation has mainly been in the young pig population," Evans said today by phone. "You will not lose all your older pigs, and they become part of the solution. Over time as the immunity level rises, the effects become less and less acute."
Sows that survive contact with the virus will develop antibodies they’ll pass on to their litters, according to Evans.
Based on the pig-production cycle, increased resistance and immunity would appear six to nine months after the "original crest" of the outbreak, Evans said. It’s important to halting the spread to new states because those pigs will be susceptible to the virus, he said.
The impact of the disease will "definitely" decline by the end of the year, the OIE deputy director general said.
A severe winter in the U.S. may have contributed to spreading the virus, with frozen manure on trucks making full removal of potentially infected feces difficult, Evans said.
U.S. and Asia
The U.S. virus is genetically similar to that circulating in Asia, suggesting the disease may have been imported, Evans said. Symptoms such as watery diarrhea and vomiting can apply to other diseases, complicating identification, he said.
U.S. biosecurity is probably "not quite" at the level of Europe, which has faced more livestock disease challenges, according to the deputy director general.
"It’s a rude awakening to the realization that biosecurity is important in any livestock production system," Evans said. "The U.S. has a very credible surveillance system in place, and a high level of awareness in the industry on the importance of surveillance."
The porcine epidemic diarrhea virus doesn’t affect people and is not a food safety or food security issue, Evans said. "But it definitely is devastating at the production level."