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New vaccine to battle PRRS
Each year swine producers in the U.S. lose $664 million to porcine reproductive and respiratory syndrome (PRRS). An Ohio State University researcher has created a unique vaccine to battle the disease.
Renukaradhya Gourapura, associate professor in the Food Animal Health Research Program, a division of the Ohio Agricultural Research and Development Center (OARDC), created the vaccine. It uses an inactivated virus to eliminate adverse reactions to pigs such as abortion, sick piglets, and further spread of the disease. The new vaccine is encased in a biodegradable nanoparticle, which improves the efficiency of absorption into the pig’s immune system.
"Our tests have shown that two doses of this vaccine, administered intranasally along with a potent mucosal adjuvant, achieve 100% protection in pigs against genetically variant PRRS virus," said Gourapura, who started working on this project in 2009.
Current PRRS virus vaccines are injected into the subject’s muscle. This method is not very effective in terms of immunity in the respiratory system, where the disease is the strongest. According to Gourapura, the vaccine is administered directly in the nose into the respiratory system. The cells absorb the vaccine and induce a local mucosal immunity against the virus.
The PRRS virus vaccine is made from a biodegradable polymer of lactic acid and glycolic acid, known as PLGA. The first time a PLGA-based nanotechnology is being used with food animals, the U.S. Food and Drug Administration approved the agent for use in human vaccines and cancer drug delivery systems.
"Our vaccine has proven to be completely safe in tests so far, with no side effects associated with it," Gourapura said. “The use of nanoparticles allows the vaccine to stay in the pig's system for four to eight weeks without being degraded. The vaccine is also shelf-stable. We have tested it for one year without showing any loss of quality."
PRRS was first recognized in 1987 and was isolated by OARDC associate director David Benfield and others in 1992. It is estimated today that 60% of herds in the U.S. have symptoms of PRRS. Symptoms include: fever, respiratory distress, anorexia, abortion (in pregnant sows), and weakening of the immune system, which leads to the pig's susceptibility to other diseases.
Ranked ninth in U.S. pork production, Ohio has had outbreaks become more common since 2010, even among vaccinated sow herds. The virus can cause a 10% to 20% mortality rate in the heard, leading to significant economic loss for the industry worth $681.5 million and 10,000 jobs. Gourapura says the vaccine has been successfully tested at Ohio State, but the next step is to field test it in hundreds of pigs in commercial herds.
The cost isn’t released yet, but it seems to be affordable. "The vaccine appears to be commercially feasible," he said. "Once it is produced in large quantities, its cost should be similar or just a little more than that of currently available vaccines for PRRS." The market for the vaccine is there. Industry leaders have reported sales near $100 million each year. The vaccine could potentially be marketed to operations in Europe, China, and other swine-producing countries.
Gourapura said his vaccine could also become a model for the development of similar nanoparticle-encapsulated vaccines for other diseases affecting pigs and other food-producing animals.