A Field Guide
TO COMMON WILDLIFE DISEASES
AND PARASITES IN ALASKA

TRICHINOSIS

Bears and walruses are common hosts for trichinosis.

• Trichinosis is caused by a roundworm called Trichinella spiralis.
• Lifecycle: The larvae of the roundworm grow and mate in the intestines of the host animal. The females deposit larvae that travel in the blood to other parts of the body where they form cysts in the muscle. Animals become infected when they eat meat with cysts.

• Trichinosis occurs in bears (black, grizzly and polar bears), wolves, foxes (arctic and red), wolverine, lynx, walruses, seals, and ground squirrels.
• In Alaska, trichinosis is common in many species and locations.
• Humans and dogs can also get trichinosis by eating infected meat.

• Animals may appear healthy.
• Trichinosis is hard to detect when butchering because there are few signs.
• Larvae form cysts usually in the muscles of the jaw, tongue, and diaphragm.
• Cysts may not be visible to the naked eye.
• Animals may have swollen intestines with small bruises.
• Affected muscles and associated lymph nodes (glands) can be soft and swollen.

How can I protect myself?

• You can get trichinosis by eating meat from infected animals that has not been thoroughly cooked.
• All bear and lynx meat should be considered possibly infected.

Can I eat the meat?

• People can get trichinosis by eating infected meat that has not been adequately cooked.
• Meat should be well cooked (internal temperature of meat should be at least 150° F).
• Freezing, smoking, drying, salting and microwaving may not kill the larvae.
• Do not feed infected parts to dogs.

• Tongue and jaw muscles, diaphragm
• A large sample of muscle (at least 4 oz.) is required for analysis