Veterinarian sees changes to three high-risk swine viruses

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Three diseases affecting finishing hogs — Senecavirus A (SVA), porcine sapelovirus and erysipelas — have undergone changes over the past year that warrant the pork industry’s attention, according to Aaron Lower, DVM, Carthage Veterinary Service.

“We’ve been sporadically identifying all three of these over the past year,” Lower said. “Generally, the economic impact has been minimal, but the risk is relatively high with all three.”

Lower incidence of SVA

SVA “looks like it is starting to decrease in incidence,” Lower said at the 2018 Carthage Veterinary Service Swine Conference. “This isn’t a large-impact disease, but it is very disruptive to you and your packer.”

SVA mimics foot-and-mouth disease (FMD) and must be treated like a foreign animal disease until the government rules out FMD through diagnostic testing.

The disease appears to be a hot-weather virus because most of the outbreaks occur from July to November, Lower noted.

“My belief is these pigs show up with lesions when we put them under a lot of stress — heat stress and marketing stress,” he said. “This makes us wonder if the virus may be more widespread than we thought; it just takes a certain set of co-infections or stressors to show up as a clinical virus.”

Porcine sapelovirus emerges

Until he saw porcine sapelovirus, Lower said he didn’t believe the neurological virus existed. It is real, however, and on the increase, though still very low in incidence.

“The virus is found in both healthy and diseased animals,” Lower said. “Identification of the virus doesn’t mean you will have clinical signs. When it moves to clinical cases, you will see diarrhea, stillborns, mummies.”

The virus also can cause neurological damage including a complete loss of body movement.

“These pigs are 100% mortality once they start on this progression,” he added. “They don’t respond to treatment and all must be euthanized.

“Cases come on over a 3-week period and how long it stays is variable,” Lower said. “We’ve seen two or three cases and then it’s gone. We’ve heard other reports where in 1 to 1 ½ years they’ve continued to have issues with it.”

Lower recommends obtaining a diagnosis using one of the euthanized pigs.

“There’s a lot to learn on this virus,” Lower said. “So, if you see it in the flow, give us your observations on how it is spreading between sites, [its]consistency and if there are other drivers of it.”

Erysipelas reappears

Erysipelas cases have started increasing in number, he reported. “I usually get two to three calls a year on it in grow-finish or gilts. But it got to four cases a month in multiple flows [last] winter,” Lower explained.

“Because we don’t see much erysipelas, a lot of [pig] flows don’t vaccinate in grow-finish because they haven’t been able to justify it.”

The key to minimizing the impact of erysipelas and other finishing diseases is early identification followed by fast treatment.

“Make sure you’ve got it identified correctly and communicate with your team and packers with respect to the clinical descriptions and the problem,” Lower added.

 

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