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.
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
is sometimes encountered in the flesh of
freshwater fish or fish that are anadromous (migrating from salt
water to fresh water for breeding).
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.
The larvae of these parasites are sometimes found in the flesh
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.
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.
Consumers of raw and underprocessed fish are the target
population for diphyllobothriasis.
Food and Drug
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a
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