INDIANAPOLIS, Ind. — Seneca Valley virus (SVV) isn’t a new disease in swine, but until this year it has been rare enough in U.S. pigs that not much is known about it here.
In Perry, Iowa, the newly established Swine Health Information Center (SHIC) is grappling with amassing data to understand SVV better. So far in 2015, Indiana State Board of Animal Health (BOAH) swine specialist Dr. Craig Bowen said there have been more than 30 cases reported in the United States.
This doesn’t sound like much, but the SHIC notes it is "much higher than the 2-3 sporadic cases per year that is our historical experience."
Morbidity, or incidence of disease, is not uniform. Bowen said so far it has varied from just a few in a herd, to one that was 80 percent affected. One herd with more than 30 sows had only two that displayed clinical signs of SVV – and this was after prolonged contact, noted Bowen.
SVV doesn’t seem to be as contagious as the porcine epidemic diarrhea virus (PEDv) swine producers have dealt with for three years, but at the same time, he admitted "not a whole lot is known about (Seneca Valley) virus."
Mortality, or the rate of death, seems to be low. The SHIC noted in a group of 187 pigs coming into the country from Canada in 2007, 15 of pigs displaying symptoms were "deemed significant" by a USDA vet but none died. One case of SVV in an Indiana boar in 2010 did result in euthanasia because of progression of the clinical disease.
Three SVV cases were reported in Indiana, in two commercial herds and one 4-H case. Bowen said veterinarians are not sure where the virus came from, since there were not obvious travel vectors for the infected animals. BOAH’s concern now is notifying swine producers of SVV and urging them to report clinical symptoms associated with it – not only to understand SVV better, but because they tend to look like the much more worrisome foot-and-mouth disease (FMD).
According to the SHIC, SVV causes vesicular lesions and lameness is commonly observed. Gross lesions include multifocal, round, discrete erosive and/or ulcerative lesions on distal limbs, especially around the coronary bands, and redness and blanching of the bands.
Crusting and sloughing of the hoof wall may also be observed. Similarly, fluid-filled vesicles and multifocal chronic superficial and/or deep ulcers have been described in and around the oral mucosa, snout and nares.
Bowen said swine producers who see such symptoms should report them immediately to their vet for testing, primarily to rule out FMD. FMD is classified as a USDA Foreign Animal Disease subject to investigation; at this time, SVV is not.
"Pigs with illness or active SVV lesions should not be marketed until the lesions at least start to resolve. We can’t afford to have a packing plant shut down because of SVV being mistaken for FMD and stopping processing and commerce," stated the American Assoc. of Swine Veterinarians’ Swine Health Committee.
"At the same time, we can’t also become complacent and assume that active lesions are SVV, thus not alerting state or federal officials, whether on the farm or in the packing plant. Doing so puts pork producers, veterinarians and all of our industry at risk.
"Discussions are taking place with USDA and the packing companies about appropriate communications and responses about pigs that have had SVV, are healing, have had a FMD-negative test and are going to be presented to the market."
According to SHIC Executive Director Dr. Paul Sundberg, SVV has been found in cattle and other animals, "so it’s not specifically a pig disease, but we’re certainly concerned about it." SVV does not appear to cause clinical symptoms in humans.
Much more specific information on SVV is available on the SHIC website at http://swinehealth.org/emerging-disease-information – including a link on that page to a PDF fact sheet document.
At BOAH’s quarterly meeting last Thursday, Bowen also noted as incidents of Indiana PEDv have dropped off, the agency has reduced the frequency of its special reports on the disease and is down to quarterly updates (at its busiest, it was every two weeks).
He said there has been only one new case of it reported since June.
