The introduction of two new vaccines has helped turn the tide in the battle in Canada to contain a potentially deadly condition that’s taken a huge toll on swineherds around the world.
Porcine Circovirus Associated Disease (PCVAD), previously called Post-weaning Multisystemic Wasting Syndrome (PMWS), is a viral disease that typically affects young pigs, weanlings, from eight to 16 weeks of age. However, symptoms tend to manifest themselves in the grower phase and the disease is often fatal. The disease, first characterized in western Canada in 1995 became widespread worldwide since then.
Research shows the primary cause is a common pathogen, porcine circovirus type 2 (PCV-2). Because this organism is so common, researchers believe the disease requires some additional triggering mechanism for the infection to result in symptoms. Earlier this year two companies received emergency licenses to distribute vaccines in Canada. The company Merial developed Circovac, and Intervet developed the other product, yet unnamed. Two more products may receive approval within the next 12 months.
Circovac, administered to the sow before she farrows, helps increase the amount of protection passed on from the sow to the piglet in the colostrum. The piglet receives the Intervet product at weaning, about three to six weeks of age, to stimulate its own immune system making it more able to fight off infection. “In North America, or more specifically Canada, it appears we are past the point of crisis,” says Dr. John Harding an associate professor with the Western College of Veterinary Medicine at the University of Saskatchewan in Saskatoon.
His sources and colleagues in Quebec and Ontario report the number of cases and the severity of disease has declined in the last two to three months.
“In western Canada it remains a sporadic issue,” says Harding. “If anything, the number of cases is probably declining although it still remains quite serious in some particular farms.” Harding’s information shows the U.S. still has discreet areas still seeing fairly high levels of clinical disease and quite a concern in some specific areas. He says the most significant factor judging by the reports from the field, would be the use of the two vaccines in the last three to six months.
“I think those vaccines are having a substantial dent in the amount of cases that we have,” he said. “Controlled studies will report over the next one to two years and it’s hoped the vaccines are doing their job and this disease will continue to decrease.”