Common gut bacteria identified as cause of pig ear necrosis

It's a problem that's made its way through pig farms around the world for decades, with no clear cause or solution. But new research from the University of Saskatchewan (USask) has identified the cause of pig ear necrosis, a painful and troublesome affliction that causes the ear tissue of pigs to rot away.

"It's been around for so long and we were unable to effectively control it," said Dr. Matheus Costa (DVM, Ph.D.), an associate professor with USask's Western College of Veterinary Medicine (WCVM) and an expert in swine health. "I think now we can finally take a step toward controlling the disease and improving the quality of life of these animals."

Costa said pig ear necrosis was described in the 1960s, but it has been nearly impossible to identify what causes it. Costa described it as a very "ugly" condition that causes a pig's ear tissue to "necrotize," or progressively rot. It is painful and damaging for the pigs, causing lesions and affecting their growth and profits for producers.

"It was previously described as a multifactorial disease, likely because we didn't know what was causing it," Costa said. "We kept seeing it, it was always there, everyone talked about it ... and obviously the pigs suffer."

While pig ear necrosis itself is not a fatal disease for pigs, the bigger issues lie with the secondary ailments that result from pig ear necrosis. The infection is painful, affects growth and meat production, and often leads to injudicious use of antibiotics.

Through clinical research at USask, Costa and his team identified an unlikely culprit—a rather common bacteria called Fusobacterium necrophorum found in the gastrointestinal tract of many mammals, including humans.

Pig ear necrosis only occurs when the bacteria are transferred via saliva through biting or chewing ears, an identified habit of pigs. Costa and his team were able to confirm their findings in a lab setting, and their research was recently published in the journal PLOS One.