Skunks blamed for rise in livestock rabies cases

Farm Forum

With the number of cases of rabies in livestock in South Dakota at its highest level in more than a decade, it’s worthwhile for ranchers to be on the lookout for the virus in cattle, health officials say.

There were 16 cases of livestock rabies reported in the state last year, according to the state Department of Health. That’s up from four cases the year before. It’s the highest total since 1999, when 22 cases were reported, said Lon Kightlinger, state epidemiologist.

“It’s driven by skunks,” Kightlinger said, of the number rabies cases in cattle.

His theory is that there are more skunks around and, as a result, more rabies. Skunks are the main carriers of rabies, he said.

Reports of unusually high numbers of skunks were reported across the state last year, including in Aberdeen. There were so many of the varmints that the Aberdeen animal control officer ran out of traps last fall. Kightlinger, who’s based in Pierre, said the state capital also had a skunk invasion. Numbers were “shockingly high,” he said.

While it’s speculative, it makes sense that interactions between skunks and livestock have increased, said Russ Daly, a South Dakota State University Extension veterinarian. With dry conditions, maybe more cattle were on the move looking for good pastureland, maybe skunks were moving more, or maybe ranchers were more closely watching their cattle, he said.

Cattle are curious, Kightlinger said. Calves, especially, are apt to wander up to a skunk, which could lead to being bitten.

Rabies is a cyclical virus, so the numbers tend to spike every 10 years or so, Daly said. Just why, though, is hard to say, he said. The 16 cases in South Dakota last year is huge number, Kightlinger said. He said there were 61 cases of animal rabies confirmed in the state in 2011, including 37 in skunks, three in rats, three in horses and two in cats.

Daly said that in the 1980s, hundreds of livestock in South Dakota were diagnosed with rabies. Improved vaccination practices have likely helped drive that number down, he said.

In order for a case of rabies to be counted, it first has to be noticed, Daly said. There could be instances in West River, for example, where a rancher doesn’t ever see a sick cow, only the carcass, he said.

Signs of rabies can often be vague and hard to discern from other illnesses. But, Daly said, a behavioral difference is one trait to look for. A docile cow might get loud and bellow a lot, he said. It’s smart for ranchers to be aware of rabies as a potential problem so they don’t come into contact with rabid livestock, he said.

When in doubt about an illness, call a vet, Daly said. If needed, a vet can send the animal’s brain into a lab for diagnosis, he said.

Rabid animals are dangerous, and even a cow’s saliva can lead to infection, he said.

Kightlinger said he knows ranchers often like to take matters into their own hand and might try to feed a cow a pill or stick their hands in a cow’s mouth. That’s a good way to get exposed to the virus, he said. If 16 cases of livestock rabies were reported in the state, 16 people probably were exposed to the virus, he said.

In animals, rabies is fatal. There is no treatment, though vaccination is an option, Kightlinger and Daly said. They said it would be uncommon to vaccinate an entire herd of livestock, but it is wise to vaccinate a cow that might be shown by a 4-H’er or taken to a petting zoo.

All pets should be vaccinated for rabies, Kightlinger said. And getting barn cats or farm dogs vaccinated is also a good idea, Daly said.

He said cats and dogs can spread rabies not only to humans but to livestock, though that would be far less common than the virus being spread to a cow by a skunk.

If you see a stray skunk in town, Kightlinger said, call the city animal control officer. And avoid contact with skunks in general, he said, referencing an instance in Brown County a couple of years ago in which a resident nursed and sold baby skunks after the mother had died. Some of the baby skunks wound up being rabid, he said. Skunks cannot be vaccinated for rabies, he said.

There hasn’t been a rabid human in South Dakota since 1970, but people still need to be aware of the virus, Kightlinger said.

“People don’t really pay attention unless they’re bitten by an animal, it seems, or their dog gets sick,” he said.

Cases of rabies in livestock in South Dakota

2012É16 2011É4 2010É5 2009É4 2008É2 2007É2 2006É4 2005É14

2012 cases of rabies in livestock by county in

South Dakota

BrookingsÉ2 CorsonÉ1 DayÉ2 DeweyÉ2 GregoryÉ1 HaakonÉ2 HardingÉ1 HutchinsonÉ2 McPhersonÉ1 MinnehahaÉ1 RobertsÉ1