AMES, Iowa – A once uncommon virus in pigs that’s appearing this year with greater frequency should keep pork producers and local veterinarians vigilant but is no cause for panic, according to an Iowa State University veterinarian.
The ISU Veterinary Diagnostic Laboratory has confirmed around 100 cases of Senecavirus A in pigs in seven states since July, said Chris Rademacher, a senior clinician in veterinary diagnostic and production animal medicine.
In a normal year, the U.S. swine industry encounters only a handful of cases, Rademacher said, and veterinarians have taken notice of this year’s increasing frequency.
Senecavirus causes blisters, or vesicles, around the snout, mouth and hooves of an infected pig, but the symptoms are rarely fatal and don’t last long. In fact, the virus rarely requires any sort of treatment, Rademacher said.
“In severe enough cases, it can cause lameness, but it’s generally not lethal for an adult pig,” he said. “The pigs heal quickly, usually in a matter of a few days.”
Of greater concern is that the symptoms of a Senecavirus A infection mirror those of several foreign vesicular viruses the American pork industry is working hard to keep outside U.S. borders. Those diseases include foot and mouth disease, swine vesicular disease, swine vesicular exanthema and vesicular stomatitis virus.
Rademacher said those viruses aren’t found in the United States, and the discovery of any of them among the U.S. swine herd could have serious trade implications for producers who export pork.
“The biggest concern with this uptick in Senecavirus is that producers may get numb to these symptoms and quit reporting them, since this disease isn’t a huge economic threat,” he said. “That would be a mistake because the symptoms are so close to those foreign viruses that we need to stay vigilant.”
He urged producers who notice vesicles on any of their pigs to report the symptoms to their local veterinarian. Local veterinarians can observe the symptoms and get state and federal officials involved for a diagnosis if necessary.
Rademacher said the Senecavirus A strain may have evolved into a pathogen that has the capability of spreading more easily among swine herds, which would account for the rise in cases this year.
The virus was first discovered in the United States in the late 1980s. Comparisons of samples of the virus taken back then to recent samples shows that between 10 and 15 percent of its genetic makeup has changed, Rademacher said. And today’s strain of the virus is similar to a strain that resulted in an outbreak in Brazil in 2014.
Rademacher also noted that Senecavirus A cannot infect humans and doesn’t make pork less safe to eat.