Bulletin #1002, Echinococcus granulosus canadensis (EG) in Maine Moose: Suggestions for Dog Owners

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By Anne Lichtenwalner, DVM, Ph.D., University of Maine Cooperative Extension, and Lee Kantar, Maine Department of Inland Fisheries and Wildlife.

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bull moose
Photo by Gail Smith

During a 2012 survey of Maine hunter-harvested moose, Echinococcus granulosus (EG) cysts were found in a number of moose lungs. EG is a very small tapeworm that has a two-part life-cycle: one in canids (coyotes/foxes/domestic dogs) and the second in ruminant-type animals, such as moose or sheep. Although EG can infect humans, the form that is known to do so most often is the domestic, or sheep-dog, genotype. Genetic testing of the Maine tapeworms found that this EG is the northern, wild-type form. This form is unlikely to cause human disease. However, finding EG in moose suggests that likely wild canids (such as coyotes) in Maine are infected and that possibly domestic dogs are infected as well. If dogs are infected, then their owners could be exposed.

The risk to people is low, but breaking the tapeworm cycle is simple, and can reduce that risk even more.

  1. Wear waterproof gloves when dressing out game.
  2. Keep your dog away from game (moose/deer) viscera.
  3. Thoroughly cook all game meat.
  4. If your dog might contact dead game (or gut piles), use a wormer effective against tapeworms at least twice yearly.
  5. Talk to your vet about a plan to minimize the risk of EG exposure.

How do moose get EG?

Moose may browse where infected wild or domestic canids have defecated. The eggs are in the canid feces, and these eggs are the form that infects the moose.

What is a “canid”?

Canid is a term referring to a dog-like animal. For this form of Echinococcus, canid hosts could include coyotes, wolves or domestic dogs.

What happens when the moose gets EG?

There will be cysts, or fluid pockets, in the moose’s lungs or liver. These cysts contain the scolex, which is the infective form for the canid host.

How does the canid host get EG?

The canid (wild or domestic) consumes the cysts from the moose lung or liver. These cysts are still infective after the organs are removed from the moose (“gutting”).

How could a human get EG?

The adult tapeworm lives in the intestines of the canid host, and eggs that are infective to the moose, or to humans, are passed in the canid’s feces. Humans may become infected by ingesting eggs of the parasite picked up by contact with canid feces; this could happen with poor hand-washing practices.

For more information, visit Maine.gov’s Maine Department of Inland Fisheries and Wildlife website (www.maine.gov/ifw).

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

© 2013

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