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Dogs and sheep share a common parasite

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“It is not a food safety issue. It’s a cosmetic issue.”

Sheep and their guard dogs are a natural pairing, but the trusted partnership can also host a harmful tapeworm, says Dr. Kathy Parker, a veterinarian with a mixed practice in the Three Hills area.

Speaking at a seminar in Stettler Oct. 23, Parker said C. Ovis, which can be found in sheep, is the larval stage of a tapeworm which infects dogs.

“It is actually a dog tapeworm,” she said. “The dog sheds the eggs in its feces and then sheep or deer eat the contaminated grass and host the larva. It’s the larval stage that they are condemning the carcasses for in the packing plants. Your sheep is an intermediate host for this worm.”

The larva takes some time to develop in the sheep and is only seen in older lambs and sheep. The eggs are in a dormant stage when they are shed from the dogs, and become active once they get into the sheep.

“It is not a food safety issue. It’s a cosmetic issue. Those are actually blighted cysts that are in there,” said Parker, who has her own flock of sheep. The little white cysts be found inside the sheep are generally no longer infectious. The immune system of the sheep generally kills the larva, but the process creates a cyst in the sheep meat. Feeding dead sheep to dogs can transmit the larva back to the canine, and Parker does not recommend this practice.

Parker told producers to assume their dogs have the problem, and to worm the dogs often. She recommends worming every month. “There’s no point in doing a fecal test because you won’t see the worms or the eggs,” she said.

Parker recommends Biliticride, a tapeworm killer which can also be used to treat tapeworms in humans. This medication will have to be prescribed by a vet, and may require talks between the veterinarian and a pharmacist.

“It’s your veterinarian’s prerogative whether they want to give the scrip or not,” she said. She recommended having a discussion with the veterinarian about the medication. “If you get rid of the adult tapeworms in the dog, it can’t get back into the intermediate host (the sheep) and spread back to the dog,” she said.

There is no medication to treat C. Ovis, the larval stage, in the sheep, so treating dogs is the best step of defence. The parasite will do more harm to the dogs than to the sheep.

About the author


Alexis Kienlen

Alexis Kienlen lives in Edmonton and has been writing for Alberta Farmer since 2008. Originally from Saskatoon, Alexis is also the author of two collections of poetry, a biography, and a novel called "Mad Cow."



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