A team of veterinary researchers recently discovered a novel virus in the central nervous tissues of young pigs with polio-like weakness in their hind legs. The team was led by Paulo Arruda, DVM, Ph.D., an assistant professor of veterinary diagnostic and production animal medicine at Iowa State University, in an effort to investigate samples from 11-week-old pigs on a farm near the East Coast that couldn’t walk due to a mysterious weakness in their hind legs. The diagnostic team, which also included researchers from the University of Minnesota and Kansas State University, found microscopic lesions in the pigs’ central nervous tissues containing a novel sapelovirus that researchers hadn’t previously encountered. Sapeloviruses belong to a family of viruses commonly found in pigs, but this particular strain was different from all other sapeloviruses previously described, Dr. Arruda said. “We’re collecting evidence, sort of like in a forensic investigation,” he said. “But we still have a lot of questions that need to be answered about this virus.” For instance, despite the evidence collected, the team isn’t completely sure the virus is responsible for all the lesions in the spinal tissues or if there’s another unknown factor contributing to the neurological symptoms, according to Arruda. Lack of scientific evidence regarding the virus means it’s impossible to know just how widely it may spread, Arruda said. But the epidemiology of other viruses within its family leads Arruda to believe this particular strain may be fairly common on U.S. hog farms. However, only a small percentage of pigs with the virus likely will display symptoms, he said. The economic impact posed by the virus remains unclear, he said. Farms dealing with the disease may lose one or two percent of pigs, making it a concern for individual producers, he added. Arruda said there’s no evidence the virus makes pork unsafe to eat. The researchers used advanced techniques such as next-generation sequencing to map the entire RNA and DNA genomes of pathogens within the samples. That data allowed the diagnosticians to conclude the virus was novel and present in high numbers within the spinal cord samples of the affected pigs, according to Iowa State University.
