Biosecurity continues to puzzle us, as does the seemingly endless ability of the porcine reproductive and respiratory syndrome virus to circumvent our best biosecurity efforts. Either the virus has magical powers or our efforts fail to hit the real exclusion targets.

For another example, in less than two years porcine circovirus associated disease swept across the U.S. pork industry. Unlike PRRS virus, PCV2 is one tough customer when it comes to survival in the environment. We believe that PCVAD is attributable to a new PCV2 agent or co-agent that seems to jump tall buildings and spread faster than a speeding bullet. 

The unsettling thought from this phenomenon is the unprecedented way that a new virus has spread, affecting all types of farms and production systems. PCVAD was a shot across the bow — a warning of what could yet come. 

In the environment, PCV2 is quite similar to the foot-and-mouth disease virus. Both are very stable, resisting disinfection, drying and heat. Of course, FMD would not be allowed to spread with the same reckless abandon that PCVAD was given. Considering our recent track record with a new, emerging disease, it would likely get out of the gate much faster than even Great Britain’s recent case.     

We typically fail to understand the life cycle of those agents which are best excluded. This incomplete knowledge leads us to generic and general approaches that add cost and often fail to meet expectations. The hope is to prioritize our efforts toward interventions that have the greatest impact.

The American Association of Swine Veterinarians recently took responsibility for the PRRS Risk Assessment Tool, and with assistance from IowaStateUniversity it continues to develop. Eventually this tool will help us understand how new disease agents enter farms, risk factors that leave us vulnerable, and the success prospects for specific interventions. Hopefully it will significantly improve how we spend our biosecurity dollars.

Here I’d like to share an excerpt from my biosecurity comments in the September quarterly newsletter of PRRS-CAP (Integrated Control and Elimination of PRRS USDA‑NRI and NC‑229), which is the centerpiece of current PRRS research, control and elimination. 

Today, biosecurity is a relative term and/or strategy that’s based on the needs and expectations of the farm, site, system or region. To be effective, it must consider four inter-related parameters:

1. It must be simple enough to become a part of the daily routine, the company, the farm and the culture.

2. It must be economically sound and based on scientific evidence and experience.

3. It must be ordered by risk magnitude and intervention costs — targeting the greatest risk first and determining if the potential economic gains outweigh the cost.

4. The ecology of the agent or agents to be controlled or excluded must be understood and managed by a Hazard Analysis and Critical Control Point series of interventions, targeting specific points.

Next, there are two independent biosecurity spectrums: internal and external.

  • Internal biosecurity focuses on controlling agents already present in the farm or system.  This could be considered bio-management, and in the case of a new disease, bio-containment. 
  • External biosecurity concerns itself with exclusion, more specifically bio-exclusion.

Internal and external components should remain independent of each other. However, poorly implemented internal methods are often a sign of lapsed or weak external methodology. While external methods are significantly more difficult to monitor and maintain, they are essential for bio-exclusion. 

First off, farm gate security is essential to protect the barn environment. Additionally, farm shower-in-and-out procedures go a long way in excluding most human-fomite-delivered pathogens. Transport protocols must be controlled and managed to a standard comparable to a surgical suite in a busy hospital.

Transport biosecurity is our greatest “controllable” weakness. Yet, trailers are difficult to clean properly, and regardless of disinfectant effectiveness, they can’t be thoroughly sanitized. I am always amazed when disease disaster strikes we focus on mysterious aerial assaults, but not on the managers from whence our biosecurity weaknesses come.

As an example of what can be done, Ben Woolley, Sunterra Farms Ltd, recently reported that adding a clothing/boot barrier to the company’s northern Iowa finishing barns has successfully excluded PRRS most of the time. Prior to making these minor changes in biosecurity, 90 percent of the barns were PRRS-positive at slaughter time. After implementing the new biosecurity standards that shifted to 80 percent of the sites being PRRS-negative. 

As we move forward, adding costly biosecurity interventions and looking for the silver bullets, we should not forget the value of maintaining common-sense strategies.