Our March annual meeting program was filled with topics associated with the porcine epidemic diarrhea (PED) epidemic that plagued the swine industry with high mortality during 2013 and 2014. Topics included case reports, diagnostic tools, nutrition, treatment, control, elimination, epidemiology, biosecurity, immunology, and vaccination. The proceedings papers from this year’s meeting, along with several of the preconvention workshop papers, will serve as a collective reference for PED virus for years to come. It continues to amaze me how much information was gathered and knowledge generated and how many tools were developed in the short time of a year and a half from entry into North America. In the hallways of the hotel I heard international guests saying they were grateful North America became infected because they knew the Americans would figure out how to manage it. Well, indeed we did!
In Nebraska, looking back on last winter, PED was not a big problem, but it has not been eliminated and could threaten sow herds next winter as immunity declines. Many growing-pig sites have become reservoirs for future outbreaks. I expect to see more PED in the winter of 2015-2016 than the winter of 2014-2015.
After focusing on PED virus, we took time in the last session of our annual meeting to look ahead. The Tuesday morning session asked the question “What’s coming next?”
Dr Patrick Webb reviewed the history of previous national swine disease eradication efforts and shared some of the risks that we may face in the future. He made it clear how pig production has changed to a highly mobile industry. North America exports approximately 30% of its pork. Not only is pork moving internationally, pigs are moving all over the country from farrowing sites to finishing sites. Dr Webb estimated there are “1 million pigs on the road” every day. This explains the potential challenge to controlling the spread of a foreign animal disease (FAD).
Dr Beth Lautner from the United States Department of Agriculture (USDA) informed us of other risks, including the estimate of as many as “1 million viruses in vertebrates.” Since the PED epidemic, she found renewed interest in the USDA Veterinary Services “Swine Futures Project,” which has recommended expanding the current FAD management system to encompass emerging animal disease detection and response capability.
Dr Max Rodibaugh, a practitioner from Indiana, reflecting on his PED experience, gave us good advice for future trans-boundary diseases. Maintain transparency and traceability. Go out to the farm, look at the pigs, and collect samples. He cited the “Got Tonsil” program as a good example for disease monitoring.
The highlight for Tuesday’s session was Dr Robert Desrosiers’ presentation. He reflected on the past and looked into his crystal ball. Dr Desrosiers is credited with voicing caution to prepare for PED virus before it came to North America. He looked at past major swine diseases and classified them as being transmitted either directly or indirectly. Indirectly transmitted diseases are more difficult to control because they are carried to other farms by means other than pig movement, such as aerosol spread or fomite cross-contamination. He believes “emerging pathogens of the future are inevitable.” But Dr Desrosiers’ quote of the meeting was If you don’t look behind, your behind may suffer. He said, “Look back, North America has not been able to control any indirectly transmitted swine disease for 40 years,” ie, Actinobacillus pleuropneumoniae, porcine reproductive and respiratory syndrome, porcine circovirus type 2, PED. He believes North American pig production, with pigs moving from sow farms two or three times per week, is vulnerable to a pathogen that requires federal restriction of pig movement, yet will have been disseminated across the country before a response can be made. The potential is there to paralyze all animal movement: PED is merely a wake-up call.
What might the next trans-boundary disease be? Dr Desrosiers points out that approximately 75% of emerging human diseases are zoonotic. He suggests a new zoonotic swine influenza virus could be disastrous. We are “persistently vulnerable” to influenza viruses, he says, and we should make plans for it. He suggests that a sustainable pig production model should also include sustainable disease containment and “does not equate with short-term profitability.”
Currently, we are watching what is happening with highly pathogenic avian influenza in the upper Midwest. It appears that neither pigs nor people are at risk, but it does bring to mind the novel H1N1 scare of 2009-2010 and the USDA swine influenza virus surveillance program that developed from it, which is still active.
We as veterinarians have a role in assessing sustainable disease containment and establishing a secure pork production system. Our novel H1N1 and PED experience, along with forward-thinking scientists such as Dr Desrosiers and the newly established Swine Health Information Center, may come together just in time for the next trans-boundary disease.
Ron Brodersen, DVM AASV President