Controlling the PRRS Virus

Dr. Scott Dee, an Associate Professor with the University of Minnesota College of Veterinary Medicine, has been conducting research on the Porcine Reproductive and Respiratory Syndrome (PRRS) virus, and is considered one of the industry's leading authorities on the PRRS virus. According to Dee, the PRRS virus is the most economically significant pathogen disease in the swine industry today, resulting in annualized losses averaging $252 per breeding female. Based on his research, he does not believe that there is much potential for a human being to spread pathogens for swine. However, his research has shown that the virus is transferred by contaminated fomites such as clothing and boots, and the most likely time when people become an issue is when they don’t follow established biosecurity protocols.

Biosecurity and PRRS

Many questions still exist in the industry about biosecurity and the spread of the PRRS virus. Based on his experience, Dee estimates that animal to animal contact or semen (animals coming from an infected source), is responsible for a least 90 percent of the spread of PRRS and other infectious diseases. Dee said that although nothing is perfect, a closed herd is definitely the safest option for biosecurity purposes. The remaining ten percent of the PRRS virus transmission can be attributed in large part to biosecurity issues relating to transportation, as of yet unidentified vectors, or birds..

Because trucks and trailers are used primarily to transport animals to buying stations or slaughter houses, Dee considers them a high risk point. Strict biosecurity protocols should be established governing the vehicles used to transport animals. Many infectious agents, not just PRRS virus get introduced into a farm as a result of improperly cleaned vehicles. Dee recommends washing and disinfecting trucks after each load, before coming back to the farm, and also wearing disposable coveralls and boots while unloading animals.

Dee also noted that should a closed herd contract the virus, the closed herd system still works extremely well for control as well as recovering from the original outbreak.