New test could help quell spread of hog disease

Sep 16, 2013

Pork producers are worried about a virus that has the potential to wipe out entire litters of piglets.
Credit Amy Mayer / Harvest Public Media

Hog producers and their veterinarians have a new tool to help with the fight against Porcine Epidemic Diarrhea Virus (PEDV). 

The first cases of the fast-spreading disease in the United States were confirmed last spring, prompting researchers to leap into action. At this point, PEDV has been confirmed on nearly 600 farms in 17 states.

The infection is spread through contact with fecal matter and is most devastating to piglets—entire litters can be wiped out by it. That means producers have been under pressure to ensure that as hogs are moved from one farm to another the virus isn’t inadvertently spread—by infected animals or by fecal matter on boots, clothing or trailers.

Iowa State University’s Veterinary Diagnostic Lab has developed an antibody test for the virus, which will help producers decide when it is safe to transport pigs between farms. Veterinarian John Johnson, a clinician at the lab, said the original polymerase chain reaction (PCR) test can tell if a pig is infected but this new one picks up the antibodies that indicate the animal’s immune system is responding to exposure.

“If we say, 'Well, the PCR is negative but they are antibody positive,’ then the producer and their veterinarian have to assess the amount of risk they’re willing to assume on moving those animals,” Johnson said.

If both tests are negative, producers can be confident their pigs will not infect a new herd.

Sow farms that have not been infected could be threatened if animals with the virus are brought in. While piglets are quite vulnerable to PEDV, older animals can usually survive a bout with it. The virus is not harmful to humans.

Shortly after the first cases were confirmed, the National Pork Board solicited research proposals that could quickly help combat the problem. The Iowa Pork Producers Association also distributed pork checkoff funds for research, including development of the antibody test.

Johnson said researchers are still trying to understand this virus, which previously was found in Europe and Asia.

“There’s just a whole lot we don’t know yet about PED[V],” Johnson said, “as far as the whole epidemiology of the disease.”