USDA’s new influenza virus swine surveillance program tracks samples anonymously.

The National Pork Board is collaborating with the U.S. Department of Agriculture (USDA), the federal Centers for Disease Control, the National Pork Producers Council, and the American Association of Swine Veterinarians to track the changes in influenza viruses in pigs.

It is the first time that the USDA has become involved in an ongoing, non-program disease surveillance in pigs. USDA is collecting the data, but producers don’t have to worry about market restrictions due to government regulations.

“There are clear animal health and human health benefits to knowing about the status of influenza viruses out in the country,” reports Paul Sundberg, DVM, vice president for Science and Technology for the Pork Board.

“Right now we have commercial swine flu vaccines that are ‘one size fits all.’ The surveillance data being collected is going to give those (vaccine) companies information to be able to better target their products to producers,” he says.

Currently, no organized information exists as to the number of different types of influenza in pigs, which might limit the ability of state diagnostic laboratories in tracking flu viruses.

“The reason that it could be difficult to find flu viruses, human and animal alike, is because we don’t have the diagnostic reagent or test for all of the specific viruses,” Sundberg says.

“If we find there is a wide variety of flu viruses out there, but the reagents are only reacting to some of them, we can tailor more reagents to detect those others, so we can do a better job of diagnostics,” he comments.

Sundberg stresses this joint surveillance effort is about tracking all influenza viruses in swine, including swine influenza virus (SIV), and not about the pandemic strain of H1N1 influenza virus that caused such an uproar in 2009.

The pandemic strain of the flu virus sickened and killed numerous people around the globe. To determine if pork could play any role in infecting humans, the USDA’s Agricultural Research Service in Ames, IA, conducted research that showed no danger to humans or their food supply.

But unwarranted fears led to a quarantine of a Canadian hog operation, and placed U.S. hog producers on the defensive, for fear of restrictions on marketing options, according to Sundberg.

Flu Surveillance

When USDA wanted to conduct surveillance of swine herds in 2009 to determine the level of prevalence of the pandemic H1N1 strain, producers decided to ignore that request.

Sundberg emphasizes that things are different with this surveillance program that looks anonymously for influenza viruses of swine and not specifically for H1N1.
“The thing that producers and veterinarians have told us consistently is as long as the surveillance is anonymous, to go ahead and run it in the background, because we don’t even need to know about it,” he relates.

“This anonymous program means that the influenza viruses that will go into the database will be identified only to the state. There will be no information that could link the virus to a producer or to his herd,” Sundberg explains.

Three Surveillance Tracks

Surveillance data on influenza viruses identified in swine is being collected in the form of tissue samples, nasal swabs and oral fluids via three primary tracks. Most submissions will come from state diagnostic labs. Some will be collected from livestock exhibitions and first points of livestock concentration.

The third track of surveillance is human flu infections that are linked to pigs. The concern is if a producer who raises pigs gets sick, the flu virus might be associated epidemiologically with his swine herd. The producer would have to give permission before his pigs could be tested to see if they have the same virus as the one that made him sick, Sundberg clarifies.

Learning about Flu

“The main reason we still struggle with swine flu is because we don’t know the specific viruses affecting different geographic areas, and we don’t have effective tools to stop it,” Sundberg says. “This (surveillance program) will help us understand and know more about biosecurity steps, vaccines and vaccination programs.”

The sampling program is running nationwide with the cooperation of the diagnostic labs and USDA’s National Animal Health Laboratory Network. It is funded solely by USDA, including coverage of all laboratory costs.

Sundberg foresees the success of this surveillance effort could enhance all disease surveillance to include other non-program disease pathogens important to herd health.