African swine fever: Top 5 biosecurity strategies

Carthage veterinarian warns ASF is getting closer, U.S. pork producers should not get complacent.

Ann Hess, Content Director

March 12, 2020

5 Min Read
Clayton Johnson, director of Health at Carthage Veterinary Service Ltd., encourages pig farmers to fill the gaps in biosecuri
Clayton Johnson, director of Health at Carthage Veterinary Service Ltd., encourages pig farmers to fill the gaps in biosecurity to prevent African swine fever from infecting the U.S. herd.National Hog Farmer/Ann Hess

Half the world's swine population has been wiped out due to African swine fever. For U.S. pork producers, it's been advantageous to watch the spread of this devastating disease to better understand the steps necessary to stop or prevent its spread. While new ASF cases are reported each week around the world, these cases in other countries may go unnoticed by U.S. pork producers, as there are currently no cases of ASF in the United States, and the country remains vigilant in its efforts to protect farms and to prevent the spread through all ports of entry. Clayton Johnson warns ASF is getting closer and it's important the industry doesn't get complacent.

While ASF poses a few unique risks, he says it's important to remember that ASF will likely transmit throughout the industry in much the same ways as porcine reproductive and respiratory syndrome, porcine epidemic diarrhea, influenza A, Seneca Valley A and other diseases have for years. For example, Johnson, director of Health at Carthage Veterinary Service Ltd., points to the latest Morrison Swine Health Monitoring Project report.

"How are we doing on biosecurity in the United States? I'm not here to tell you that I think ASF is quite as transmissible as PED or PRRS, but we have to look at this and see that we still have gaps in our biosecurity," Johnson told attendees during the Biosecurity session at the American Association of Swine Veterinarians Annual Meeting in Atlanta. "Are we doing OK? Yes, but let's not break our arms patting ourselves on the back because PRRS is a 15% break rate so far. That's still one out of seven herds. We can't afford losing one out of seven herds to ASF."

While all farms and situations are unique, Johnson highlights what he believes are the five most important biosecurity risks for U.S. pork producers and suggestions for management strategies.

Contaminated pork: The most unique risk associated with ASF is its ability to survive in the carcass post-death or harvest. Fresh, frozen or process pork all represent a risk.

"A roadside park situation, it could happen at any of our national parks at any time. Folks traveling, international sausages with them, they have a picnic, they have a lunch, they throw away the leftovers, a wild pig comes up and roots around in it and boom, we've got it in the feral hog population," Johnson says. "I think right now, practically for our farms, we should absolutely have a no-pork-allowed policy. If you're allowing for it to come into the facility, I would reconsider that, even if it's domestic in origin."

Contaminated visitors: The ASF naïve regions of the world are becoming smaller every day, making international visitor management more important than ever.

"Exclusion is always one of the principles that we can apply in biosecurity and I think exclusion makes the most sense here. If you're going to have an international visitor that's coming from an infected country, I think you need to think about some severe downtime," Johnson says. "We've talked about five nights. I don't think there's any great science on the five nights, but that seems to be the standard or the expectation, and then those folks should probably wear clothes that you provide them and shoes that you provide them before the farm. Don't let them wear their own clothes. Go to an offsite location, change. Your vehicles really don't need to let anything in that's coming from that country."

Contaminated transport vehicles: Transportation biosecurity is a foundational component to any biosecurity program. Fortunately, Johnson says the United States has some of the best transportation biosecurity capabilities in the world, but at least one or more disinfection processes need to be implemented between loads, in order to avoid redundancy.

"We've got one million pigs on the road every single day. Million pigs on the road right now, probably 250,000 of them are on dirty trailers," Johnson says. "If we have an outbreak, what's the likelihood that it ends up in a finisher barn in Iowa? Pretty good."

Contaminated mortality management equipment: The pigs representing an index case will most likely die before a diagnosis is made, Johnson says. Those mortalities will then be managed under normal processes, putting rendering and a large number of sites at risk for ASF introduction through mortality management equipment.

"That rendering truck is going to pick up the pigs with ASF and it's going to go to three or four other farms at a minimum before it goes and drops those pigs off," Johnson says. "Probably not going to wash before it starts picking up pigs again tomorrow, so if you're still rendering, I think that's something you've really got to take a hard look at. You're likely to participate in this outbreak if you're rendering and it could get into a finishing system in the Midwest."

Contaminated feed ingredients: It has been well documented that ASF and other foreign animal disease pathogens in feed pose a significant risk for introduction into the United States.

"There's a lot that we want to do to address it and we need to be more proactive in addressing it because we can control this. There's been some really good science done to demonstrate what the downtimes need to be," Johnson says. "If we look at conventional soybean meal and DDGs, if you know a client is bringing them in from an infected country, tell them to stop, we don't want to do that whatsoever. We don't even want to take the chance with the holding times on those. The vitamins and the synthetic amino acids, if we have to bring in, let's make sure we're holding them at the right time and temperature. We may not have the Canadian program where it's officially regulated through the holding time. There's no reason why we can't do that informally as an industry right now."

About the Author(s)

Ann Hess

Content Director, National Hog Farmer

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