The yuck factor: Big game
Resembling spaghetti, these worms are slender and white, five to 22 centimetres in length, and commonly found in the connective tissue of grizzly and black bears across Canada. They most often appear in the soft tissues of the neck, groin and kidney regions. Their life cycle is tied to blackflies, but fortunately humans can’t be infected by either blackflies carrying the larvae or by consuming the meat of infected bears.
Commonly found in the lungs of infected moose and elk, and very rarely in caribou and mule deer, the larvae of these tapeworms appear as round, white cysts. While generally less than 25 millimetres in diameter, they can reach the size of a golf ball. The larval cysts are not infectious to humans, but the eggs, which are excreted in the feces of wolves, coyotes and dogs, can be.
While hunters can safely eat the meat of infected cervids, they should never feed infected lungs to their dogs. The cysts can develop into adult tapeworms in a dog’s intestine and eventually produce eggs that can be transmitted to humans, where they’ll grow into cysts in the lungs or liver. Though human infection is rare, this is one of the few wildlife tapeworms that can be of concern to hunters.
The meningeal brainworm is a tiny roundworm commonly found in eastern populations of white-tailed deer. For the most part, whitetails show no ill effects from this parasite, but when the larvae are transmitted to moose, elk, mule deer or caribou, which are not suitable hosts, the results are often fatal for the animals. In some regions where whitetails and moose coexist, in fact, brainworm is thought to be responsible for severe declines in moose numbers. However, the worm poses no public health concern, and the meat of infected animals is safe to eat.
It’s not unusual for hunters to find wart-like growths on deer and moose during the skinning process. These are a form of skin tumour. While they may be dramatic in appearance, ranging from one to 10 centimetres in diameter, they’re not infectious to humans—there’s no risk in handling the carcass or consuming the meat of animals that have these growths.
There are roughly 50 species of ticks in Canada. These bloodsuckers feed on mammals and, depending on the species of tick, they can pass along a variety of viruses, bacteria and sporozoans to humans, leading to the likes of Lyme disease, Rocky Mountain spotted fever and tularaemia. Winter tick infestations are common on moose across Canada; symptoms include considerable hair loss, which can contribute to significant moose die-offs, particularly during harsh winters.
On the bright side, there’s no risk in eating the meat from animals that have ticks. And given the vast numbers of ticks throughout Canada, surprisingly few of them attach to people. That said, hunters and other outdoor enthusiasts should check themselves regularly after spending time in the bush.
Don’t let the name fool you—ringworm is actually a fungus, not a worm. The fungal spores can survive in soil for long periods before entering a deer through cuts or abrasions. Once established in the skin, the spores spread outward from a central core, damaging tissue and hair in their path. The effects of this rare ailment are most often seen in the deer’s face and lower legs.
Ringworm affects the skin only, and there’s no risk in eating the meat of infected animals. However, care should be taken when handling or skinning an infected animal. Deer ringworm is not the same species that typically infects humans, but it can still cause a mild rash, requiring medical treatment.
These are the roundworms that can cause trichinosis in people, a serious human infection. These parasites are common in carnivores, including bears and cougars. Though generally not harmful to their wildlife hosts, trichinella can be fatal to humans. The adult worms are tiny—two to four millimetres in length—and the larvae are microscopic, so there’s no visual way to tell if an animal is infected. That’s why it’s important to ensure all meat from bears, wild felines and wild boars is cooked properly. Fortunately, infections in people are rare.
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