Foreign animal diseases and the line of last resort
By Larry Rueff, DVM
Swine Veterinary Services
Fear that a foreign animal disease like African swine fever will make its way to the US pork industry has initiated a lot of discussion about the need for better biosecurity on pig farms. I can tell you, however, that talk is one thing and implementation is quite another.
This was clearly demonstrated in 2013 to 2014, when porcine epidemic diarrhea virus rapidly spread throughout the US and Canada.
There are many points of entry that enable viruses and bacteria to get onto a pig farm. The pork industry has implemented a lot of procedures, but I think we forget that every single day brings with it the possibility of an infectious disease attack. All it takes is one slipup to initiate a devastating and costly chain of events.
One of my biggest concerns is that many people in our industry don’t realize how difficult biosecurity training can be and that people on pig farms — whether they be the caretakers or visiting veterinarians — too often just don’t get the message.
As an example, let’s use the experience at my small research barn, which holds 500 pigs. Visitors are welcome to come and see our research in action. Over the past 5 years, I’d estimate we’ve had about 300 visitors from all areas of the pork industry. In general, they tend to be highly educated people who should be able to follow instructions!
The entry to a pig farm has a lot of names such as the clean/dirty line, the line of separation, the point of entry, etc. I like to call it the line of last resort.
At my barn, there’s an outer door into a 5-foot by 8-foot entry area. You then have the option of going into one of two showers by crossing over what is considered the point-of-no-return line.
This facility doesn’t have a bench but has bright orange tape on the floor to mark the dividing area. I explain to visitors that I want them to remove their shoes, and as they do, step over the point-of-no-return line onto the clean side, without putting either foot down on the dirty side. I explain and then demonstrate this to them. As I explain and demonstrate, I am less than 3 feet away from the visitor.
Half flunk the test
I’ve never kept an official tally of how well this instruction is followed, but I can tell you that roughly half the people fail to follow that simple instruction. They step out of their shoes, and instead of stepping over the line into the clean area, they put their foot down in the dirty area and then step over the line.
A big deal? No, not if their shoes are free from contamination. Some might say having a bench might force people to refrain from putting down their foot on the dirty side, but not necessarily because I’ve seen people make the same mistake in entryways with benches.
Does anybody really believe that if the African swine fever virus is on somebody’s shoes and gets to the dirty side of a facility’s point of entry, we’re going to keep it off our pig farms? The point of entry is the last-resort line!
The experience at my research barn underscores the need for better biosecurity training and enforcement. Anyone visiting a pig farm must come clean and free of contamination. Clothing, shoes and their personal self must not have been around pigs or manure elsewhere before entering a pig farm and especially before crossing that line of last resort.
Ask difficult questions
We need to pay more attention to finding out where farm employees and visitors have been before they come onto our farms. The necessary questions can be uncomfortable to ask. Do employees go anywhere during off hours that might involve pig contact? Do they go to the local feed mill to buy feed for their animals at home? Do they have pigs at their house? (Be prepared for a shock when you ask that one!) Have they been to the county fair?
Knowledge and training about proper biosecurity procedures are vital. Clean clothes must be worn to the farm. Shoes or boots worn to the farm should be dedicated for that purpose and never worn anywhere else. There must be a required down time between the last off-farm exposure to pigs and return to the farm, with the length of down time determined by each farm.
There are other biosecurity procedures throughout the farm that need to be tackled, but focusing on the entry point is a good place to start. Let people know what they need to be aware of and what’s acceptable and what’s not. We also need to do a better job educating farm employees as well as visitors about how infectious agents can be picked up off the farm.
In short, a sharper focus on biosecurity is imperative if our pork industry is to keep foreign animal diseases like African swine fever from infecting our pigs. The line of last resort should not be put to the test.
Editor’s note: The opinions and recommendations presented in this article belong to the author and are not necessarily shared by the editors of Pig Health Today or Zoetis.
Posted on October 6, 2019