Reinfection of herds thought to be immune increases efforts to quell PEDv

Confident the causes of porcine epidemic diarrhea virus (PEDv) were being identified and managed, World Organization for Animal Health (OIE) Director General Bernard Vallat told news organizations in May that he expected to the disease “to subside before the end of the year.” Vallat said he expected the disease to stabilize once naïve herds in the United States were exposed to the virus and could develop antibodies.

However, before the month was out, Matt Ackerman, DVM, publicly acknowledged a secondary outbreak of PEDv at a farm in Indiana—reportedly the same strain that hit the farm in May 2013. The news shakes the long-held assumption that several years of immunity would develop after a herd had been initially infected with the disease.

This may also mean veterinarians’ efforts to develop herd immunity by introducing the virus to a gilt or sow in hopes that immunity would pass on to piglets may be ineffective. PEDv is known to have a nearly 100 percent mortality rate in piglets—and has killed more than 7 million to date.

The outcry from pork producers has led the U.S. Department of Agriculture (USDA) to intervene in efforts to stop the spread of PEDv. The USDA has pledged $26.2 million in funding to combat PEDv and the recently identified porcine deltacoronavirus (PDCoV). “The number of market-ready hogs this summer could fall by more than 10 percent relative to 2013 because of PEDv,” Agriculture Secretary Tom Vilsack says. “Together with industry and our state partners, the steps we will take through the federal order will strengthen the response to PEDv and these other viruses and help us lessen the impact to producers, which ultimately benefit the consumers who have seen store pork prices rise by almost 10 percent in the past year.”

The $26.2 million will be used for a variety of activities to support producers and combat these diseases, including:

> $3.9 million to be used by USDA’s Agricultural Research Service (ARS) to support the development of vaccines.

> $2.4 million to fund state-level disease management and control activities.> $500,000 for veterinarians to develop and monitor herd management plans and collect samples.

> $11.1 million in cost-share funding for producers of infected herds to support biosecurity practices.

> $2.4 million for diagnostic testing.

> $1.5 million for the National Animal Health Laboratory Network diagnostic laboratories for genomic sequencing of newly positive herds.

The USDA’s federal order also requires producers, veterinarians and diagnostic laboratories to report new detections of swine enteric coronavirus diseases to its Animal and Plant Health Inspection Service (APHIS) or state animal health officials. “The industry is already seeing herds previously impacted by the virus become reinfected, and routine and standard disease reporting will help identify the magnitude of the disease in the United States and can help determine whether additional actions are needed,” a USDA release states.

Once instances of the virus are reported, the federal order requires affected operations to work with their veterinarian, the USDA or state animal health officials to develop and implement a plan to address the virus and prevent its spread. Plans will include disease monitoring through testing and biosecurity measures to help reduce virus shed in affected animals, prevent further spread of the disease and enable continued movement of animals for production and processing, according to the USDA.

For full details of the USDA’s federal order, go to aphis.usda.gov.