Researchers at Kansas State University’s Veterinary Diagnostic Laboratory have developed diagnostic tests to identify a novel pestivirus that has been killing pigs in North Carolina. The researchers hope the diagnostic tests — quantitative reverse transcript PCR and immunohistochemistry assays — are a step toward understanding the disease. A veterinarian in North Carolina submitted a sample from a swine herd where uncontrollable shaking, or intention tremors, was observed. Nearly 700 pigs died as a result, according to the university. “The veterinarian described the tremors as similar to those seen with Parkinson’s disease in humans — but more severe,” said Benjamin Hause, Ph.D., a clinical assistant professor in the university’s College of Veterinary Medicine. “A recent report described pigs born with congenital tremors caused by a novel pestivirus similar to one we identified this past summer, but this current situation involved older pigs with disease onset from 5 to 14 weeks of age. This has a significant economic impact, especially in a situation like this where 700 animals had died.” The pestivirus family has historically been associated with important livestock diseases such as bovine viral diarrhea in cattle, border disease in sheep and classical swine fever virus, according to the university. Pestivirus infections of pigs have caused a wide range of clinical symptoms, including neurological disease, the university further noted. Dr. Hause’s research sheds new light on the pathology associated with this newly described virus. Earlier this year, Hause and colleagues at the Kansas State Veterinary Diagnostic Laboratory identified and characterized a proposed new species of pestivirus, named atypical porcine pestivirus or APPV. It was identified through metagenomic sequencing of swine serum samples submitted to the diagnostic lab. “While we identified a novel, highly divergent pestivirus in swine samples and went on to show that the virus was widely distributed in the U.S. swine herd, we had no idea what, if any, disease was caused by this virus,” Hause said. It remains unknown how often the virus causes clinical disease, according to Hause. However, he noted that he has spoken to other veterinarians who have reported seeing similar symptoms in the herds they care for. “We’re hoping the diagnostic tests that we’ve developed to detect this virus lay the groundwork to improving our understanding of disease caused by APPV,” he said.
