Common or serious wolf parasites.

Wolves are susceptible to a variety of internal and external parasites. These include at least 24 species of nematodes (roundworms), 21 species of cestodes (tapeworms), nine species of trematodes (flukes), heartworms, and three species of acanthocephalia (spiny-headed worms). Wolves are also susceptible to being infested by fleas, ticks or mites. Below is a list of the most common or serious wolf parasites.

Heartworm: Mosquitoes are the major vector of dog heartworm, Dirofilaris immitis. Once the worms end up in a canine, they will mature and grow on the right side of the animal's heart and on its pulmonary arteries. Initial symptoms include detectable heart murmurs and pulse deficits. As the problem progresses, the animal's heart may become enlarged and if the the infection becomes severe (up to 200 worms have been found in some animals), blood flow will be blocked. Heart failure may result from a major infection. Heartworm is thought to be one of the major causes of the red wolf decline that occurred in the southeastern United States during this century. Heartworm has been found in in free ranging wolves in Minnesota, and it has also occurred in captive wolf populations in the southern United States. It has not been reported in Canada or Alaska, as the mosquitoes that carry it prefer warmer climates. There are medications that can be administered to dogs and captive wolves that can prevent the disease, and it is recommended that all dogs and captive wolves living in areas where heartworm occurs be on the preventative medication.
Tags: wolf disease, wildlife

Just know a little more about Polar bears...

Polar Bears are large, meat-eating bears who are well-adapted for life in their frozen Arctic environment. They are powerful swimmers who hunt seals in the water. Polar bears can run in bursts up to 25 mph (40 kph).
Anatomy: Polar Bears are up to 10 feet (3 m) long and weigh about 1,700 pounds (770 kg); males are bigger than females. Polar bears have a small head, powerful jaws, and a black nose and tongue. They have a strong sense of smell. They have 42 teeth; the tail is small and flat. They have wide front paws with slightly webbed toes that help them swim. These bears paddle with their front feet and steer with the hind feet.
Fur and Skin: Polar Bears have two types of fur. They have thick, woolly fur close to the skin that keeps them warm. They also have hollow guard hairs that stick up and protect the bears from getting wet. These guard hairs are like drinking straws and are clear-colored (not white). The white-looking coat camouflages them well in the snow and ice. Under the fur, Polar Bears have black skin. They also have a thick layer of fat (up to 4 inches thick) under the skin that helps keep them warm.
Habitat and Range: Polar Bears live in icy Arctic areas of Alaska, Canada, Greenland, Norway, and Russia. They spend much of their time swimming in frigid seas.
Diet: Polar Bears are carnivores (meat-eaters) who frequently hunt and catch their prey in the water, often many miles from land. They are fierce predators who eat mostly seals (and some walruses and other marine mammals). A polar bear's stomach can hold up to 150 pounds. Polar bears don't drink water.
Reproduction: When pregnant, females (called sows) build snow dens in which they spend the winter; they usually give birth to twin cubs. Male polar bears (called boars) are active all year.
Classification: Kingdom Animalia (animals), Phylum Chordata, Class Mammalia (mammals), Order Carnivora, Family Ursidae (bears), Genus Ursus, species U. maritimus (meaning "sea bear").
Via; enchanted learning.com