Diphyllobothriasis

Alternative names:

fish tapeworm infection

Definition:

An infection caused by a fish tapeworm.

Causes, incidence, and risk factors:

The fish tapeworm, scientifically named Diphyllobothrium latum, represents one of the giant tapeworm species. Humans become infected when they eat raw or undercooked fish that contain tape worm larvae.

The parasite is commonly seen in areas with cold-water lakes but may also be picked up from salmon that spend part of their life in fresh cold water rivers and streams. Fish tapeworm infestation is fairly common in the Great Lakes area.

After a person has eaten of infected fish, the larva begin to grow in the intestine. The adult worm, which is segmented, may attain a length of 30 feet. Eggs are formed in each segment (proglottid) of the worm and are passed in the stool. Occasionally, a string of proglottids may be passed in the stool.

Fish tapeworm infection may lead to vitamin B12 deficiency and the subsequent development of megaloblastic anemia (pernicious anemia).