Years of scientific study and on-farm research is paying off in providing effective strategies to help pork producers prevent and control porcine reproductive and respiratory syndrome virus. According to a panel of leading swine veterinarians and disease researchers at the 2010 World Pork Expo, producers and veterinarians are making a significant difference in controlling PRRS on production farms today.

Scott Dee, DVM, Swine Disease Eradication Center at the University of Minnesota, said the development of area regional control and elimination — or ARC&E — programs, along with increased understanding of aerosol transmission and developments in air filtration, biosecurity and refined herd diagnostic techniques have proven to reduce PRRS virus transmission.

“In the last five to seven years, the swine industry has made major strides in understanding how PRRS virus spreads; what biosecurity protocols to use to prevent transmission; and how to more accurately diagnose and manage the disease when it occurs,” Dee said. “One of the more recent developments is called area regional control and elimination, which takes a ‘big picture’ approach to disease control by calling for collaboration of producers and veterinarians. This process is based on understanding the PRRS status across farms, as well as the risk factors that promote virus spread, to improve disease control within an area or region.”

The ARC&E goal is to first eliminate PRRS virus on farms in low-prevalence and low-density swine areas, along with controlling PRRS in high-prevalence, high-density areas. The end result is to improve pig performance by reducing the wild-type virus load in control areas and reducing the long-term risk of those viruses returning to PRRS elimination areas.

Currently, the ARC&E working model that is used for every region includes five completion phases.

  • Feasibility assessment
  • Pig-related identification
  • Region characterization
  • Design of PRRS elimination or control strategies
  • Execution and monitoring of farm-specific plan

"We are exploring the feasibility of implementing this approach in Minnesota and preliminary results are promising,” Dee added.

John Waddell, DVM, Sutton Veterinary Clinic, Sutton, Neb., discussed some of the newer biosecurity protocols that producers are implementing to proactively minimize the potential contact points and eliminate the direct and indirect infection sources. “Using information gained from the Production Animal Disease Risk Assessment Program, which also involves detailed disease and biosecurity assessments from nearly 2,000 swine farms, we’ve been successful at identifying, benchmarking and indexing processes that are either effective or ineffective in PRRS prevention and control,” Waddell said.  

“Because the risk assessment data is so extensive and detailed, we have a high confidence level about what protocols work, based on an operation’s production flow, geography and production facility concentration in the area, as well as disease status, vaccination methods, transportation equipment and other variables,” he added. “These types of models help us manage not only PRRS virus, but a number of other swine diseases that follow similar transmission and infection routes.”

Jean Paul Cano, DVM, professional services veterinarian with Boehringer Ingelheim Vetmedica, Inc., said that PRRS vaccination plays a critical role in most disease-management protocols to reduce PRRS infections on the farm as part of area regional control.

“Research shows vaccine use has direct benefit when used to mitigate the clinical consequences of infection and improves pig health and performance,” he said. “In addition, we’ve learned that vaccinations have indirect benefits in reducing the virus level and transmission within vaccinated populations.”

Consequently, reducing the level of PRRS virus that can be transmitted within a facility impacts the dynamics of the entire swine production system.

“Depending on the type of production facility, PRRS status and other factors, immunizing pigs against the virus, stabilizing the herd or even reducing the virus level transmitted may help producers achieve their goals,” Cano added. “Mass vaccination intervention in area regional control programs can be one of the complementary tools along with a herd closure strategy; gilt acclimation programs; and appropriate pig flow and biosecurity protocols. Vaccine can provide protection and biologic and economic benefits when PRRS-naïve pigs are placed into high prevalence areas for finishing.”

Dee noted that, thanks to advances in PRRS research, industry tools and processes, swine veterinarians and producers now have enough information to make a difference when it comes to controlling this devastating disease.

“The most effective and successful PRRS control and prevention requires a high degree of cooperation, coordination and collaboration within and among production systems in a region,” Dee concluded. “Fortunately, producers have a number of effective tools and processes available today to better help them determine current status, assess PRRS risk, measure and monitor infection status and improve their disease-management decision making.”

Source: Boehringer Ingelheim Vetmedica Inc.