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Diphyllobothrium spp.

June 10, 2008 - 7:30am
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Diphyllobothrium spp.

Diphyllobothrium latum and other members of the genus are broad fish tapeworms reported from humans. They are parasitic flatworms. Diphyllobothriasis is the name of the disease caused by broad fish tapeworm infections.

What are the syptoms of diphyllobothriasis?

Diphyllobothriasis is characterized by abdominal distention, flatulence, intermittent abdominal cramping, and diarrhea with onset about 10 days after consumption of raw or insufficiently cooked fish. The larva that infects people, a "plerocercoid," is frequently encountered in the viscera of freshwater and marine fishes. D. latum is sometimes encountered in the flesh of freshwater fish or fish that are anadromous (migrating from salt water to fresh water for breeding).

How is diphyllobothriasis diagnosed and treated?

The disease is diagnosed by finding operculate eggs (eggs with a lid) in the patient's feces on microscopical examination. These eggs may be concentrated by sedimentation but not by flotation. They are difficult to distinguish from the eggs of Nanophyetus spp.. Treatment consists of administration of the drug, niclosamide, which is available to physicians through the Centers for Disease Control's Parasitic Disease Drug Service.

What food are associated with diphyllobothriasis?

The larvae of these parasites are sometimes found in the flesh of fish.

How common is diphyllobothriasis?

Diphyllobothriasis is rare in the United States, although it was formerly common around the Great Lakes and known as "Jewish or Scandinavian housewife's disease" because the preparers of gefillte fish or fish balls tended to taste these dishes before they were fully cooked. The parasite is now supposedly absent from Great Lakes fish. Some cases have been reported from the West Coast.

What are the complications of diphyllobothriasis?

In persons that are genetically susceptible, usually persons of Scandinavian heritage, a severe anemia may develop as the result of infection with broad fish tapeworms. The anemia results from the tapeworm's great requirement for and absorption of Vitamin B12.

Who is susceptible to diphyllobothriasis?

Consumers of raw and underprocessed fish are the target population for diphyllobothriasis.


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