Nejm 1992;327:692, 696, 727; 1984;310:298

Cause:Taenia saginata(beef), T. solium(pork); Diphyllobothrium latum(fish); Hymenolepsis nana(dwarf tapeworm)

Adult worms in "definitive" carnivore hosts (dog, bears, etc), eggs in feces eaten by man or herbivorous animal ("intermediate hosts") and then encyst in muscle, etc. In T. soliumand dwarf, humans can be a definitive host or an intermediate host (muscle encystment) via autoinoculation or fecal–oral transmission, eg, in food handlers or in families; humans are only definitive hosts, ie, worm is in gi tract

Seen esp in children and the retarded. Dwarf tapeworm is most common in US. T. soliumis endemic in Mexico and in many immigrants, eg, in California

Sx:

Taenia andD. latum:rarely cause sx besides complaints of passage in stool

Dwarf: diarrhea and occasionally obstructive gi sx

D. latum:B₁₂ and folate deficiencies

T. solium:cysticercosis in brain (seizures), muscle, and skin (50%); sx may take 4-5 yr to develop when larva dies (Nejm 1984;311:1492)

Lab:

Bact:Stool O⁺ P shows characteristic ova and gravid segments in all but echinococcus

Serol:IHA titers increased with T. soliumcysticercosis

Xray:In cysticercosis: skull films and CT of head (Nejm 2000;343:420) show calcifications

Rx:

for adult forms, in gi tract, of Taenia, D. latum, and dwarf:

• Praziquantel 5-10 mg/kg × 1; 99% effective (Ann IM 1989;110:290); or
• Niclosamide 2 gm (500 mg under age 2 yr, 1 gm age 2-12 yr) once (89% cure), then 1 gm (500 mg age 2-12 yr) po qd × 5 d

for T. soliumcysticercosis: surgical excision; albendazole as above or praziquantel + dexamethasone (Nejm 1984;311:1492; Ann IM 1983;99:179)