Adult Parasite:

The adult worms are up to 2 m in length and gravid proglottids have a tightly coiled uterus full of brown eggs.

Adult D. latum

Proglottid of D. latum

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Hosts:

Mink, humans, dogs, cats, bears and other fish eating mammals(definitive).
Copepod (first intermediate).
Freshwater fish (2nd intermediate or paratenic).

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Life Cycle:

The egg hatches in water releasing a ciliated, free-swimming coracidium. A copepod ingests the coracidium and it develops into a procercoid in the body cavity. When a fish ingests the infected copepod, the procercoid will migrate to the muscles or viscera and develop to the pleurocercoid stage. If the second intermediate host is eaten by another fish the pleurocercoid will migrate to the muscles or viscera of the new (paratenic) host. When the host containing the pleurocercoid is ingested by a definitive host the worm attaches to the small intestine wall and begins to develop proglottids. The prepatent period is 3 to 4 weeks. Eggs are released from the gravid proglottids and pass out in the feces.

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Site in host where adult parasite is found:

The small intestine

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Diagnostic Stage:

Egg, or examination of the proglottid if they happen to pass in the feces.
Eggs are 75 - 45 um.

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Common Diagnostic Test

Eggs can sometimes be seen on Fecal flotation, although they don't always float.
Eggs can be found in a fecal sedimentation.

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Clinical Signs:

Usually asymptomatic in the dog and cat. In humans may cause pernicious anemia due to vitamin B12 uptake by the worm.

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Treatment:

Epsiprantel, Praziquantel

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Comments or Questions please contact: Dr. Nolan at: