Outbreaks are not like everyday life.
“People often think that there are two options of things to do in an outbreak,” says Carol Cardona, professor and Pomeroy chair in Avian Health for the University of Minnesota’s College of Veterinary Medicine. “First, you might be a case, in other words, you might be the infected farm. If that happens, then there’s going to be a very straightforward, step-by-step, regulatory process that will happen to you, and once you’re done with that, then you can become an uninfected premise again. But the other option, move as usual, is actually a lot more complicated.”
Cardona knows a thing or two about stop-and-go movements during an outbreak as her expertise was crucial during and after the 2015 highly pathogenic avian influenza outbreak in Minnesota, to help the poultry industry move forward on both the farm level and from a business continuity standpoint. While Cardona’s experience lies in working with our feathered friends, the veterinarian told pork industry members at the Allen D. Leman Swine Conference this week those same strategies could apply to moving pigs if the United States ever has an African swine fever outbreak.
There are several options for things to do with your animals if they’re not infected, which Cardona calls risk-based disease management strategies.
Go now or early marketing
This disease strategy was modeled after the third case of HPAI broke in Stearns County, Minn., a densely populated poultry region. In this scenario, producers had the option to go now or go carefully. While the go now option had the advantage of decreasing the susceptible population, there was also a greater chance of moving infected birds down the road even with a basic test and move strategy. With the go carefully option, the advantage was making sure to detect HPAI prior to moving birds using a pre-movement isolation period that would last several days. But by waiting, the farm was also at a disadvantage because the longer the birds sit in a control area, the birds are at risk of getting infected. Using a basic test-and-move strategy, there is an 80% chance of detecting infection in the flock. Following a pre-movement isolation period with additional movement biosecurity strategies, you have a 98% chance of detecting HPAI if the flock is infected.
“The results suggest that early marketing eliminated susceptible hosts, which protected several farms in Stearns County and thus may have been a useful control strategy,” Cardona says. “That’s the idea of early marketing. There’s a risk and a benefit and it’s something you would want to apply, say early in an outbreak when the outbreak is looming but not all around you, to reduce that population and not have a perpetuated outbreak in those highly dense areas.”
Go carefully or continuity of business
For risk-based permitting, the first step is to define the movement that needs to be considered and then assess the risk of that movement. Finally, that risk has to be managed.
“If it’s a high-risk movement or it’s something we don’t know much about, producers and regulators are going to be really careful. There are likely to be all kinds of requirements on you as a producer to move that product,” Cardona says. “If it’s a lower risk or negligible risk movement, regulators may allow you to manage it and check in on you every once in a while to make sure you’re continuing to do it the right way.”
Cardona says it’s important to remember during an outbreak, all state and federal resources will be entirely focused on the management of infected animals.
“The big idea here is that we’re going to conserve the time of those very few experts that we actually have out there. We won’t have unlimited state or federal resources, especially with people,” Cardona says. “These are uninfected animals that we’re trying to move. Where are our resources focused at the state and federal government? They’re making sure that those infected animals are managed. If there’s an outbreak today, those of you who have pigs on the ground, most of you are going to be in this category of uninfected, just by the odds.”
For example Cardona says for one specific movement such as moving weaned pigs from a single-source sow farm off site, actions such as crossing back and forth across the clean/dirty line, allowing the truck driver to enter the farm and allowing the crew to return to the farm after loading pigs without showering in will make that movement a moderate to high risk. Instead if the farm is respecting the clean/dirty line, not crossing back and forth, truck drivers are staying in the trailer and the crew is showering back into the farm, the movement may have a lower risk for transmission.
“The combination of the likelihood and consequences of disease spread through movement determines risk and the application of mitigations, such as targeted biosecurity measures, may lower risk to an acceptable level and that’s something that can be calculated and figured out by doing proactive risk assessments,” Cardona says. “In the heat of the moment, if the outbreak happens tomorrow, we won’t have time to put all those figures and calculations together. You’re going to be stuck with everything getting those higher risk ratings.”
Stop or hunker down
By hunkering down, Cardona says the producer would disconnect from all sources of disease and take extraordinary measures not to move. Examples of this may be to decrease the number of crew members allowed to come on the farm or to euthanize animals on-site instead of marketing culls. The farm would escape the outbreak without infection due to limited exposure but would also encounter short-term losses.
“Because no biosecurity protocol is 100% effective, the only way to make it 100% effective is to stop those movements,” Cardona says. “So, if we have a crew of a 100 people coming onto a farm and crossing the line of separation from dirty to clean, and we put them through every rigmarole we can think to get them to 99% effectiveness, we still have a 1% risk with each person crossing the line, resulting in 100% risk for the activity. If we reduce that crew to 10 people, maybe we can limit our risk to 10% by delaying that crew movement or we do it with only people on the farm, we can reduce that risk even further.”
Cardona says it’s important to remember during an outbreak, no matter what option producers choose, they will likely lose money.
“If you hunker down because of loss markets and changing cashflow, you’ll lose a lot of money. You’ll lose some money with going early due to lower yields and sort loss. You might have to market younger animals or smaller animals, but you might protect other farms. And if you go carefully, you’re still going to lose money, but that’s probably the least financially painful,” Cardona says. “It’s not about making sure you keep going during the outbreak, it’s just about surviving the outbreak, and if you do survive, you’ll make a lot of money if you’re still in business when it’s all over.”