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Key Features

Essentials of Diagnosis

  • Generally asymptomatic

  • Abdominal pain and other gastrointestinal symptoms may be present

  • Eosinophilia common

General Considerations

  • Six tapeworms infect humans frequently

  • The large tapeworms are

    • Taenia saginata (the beef tapeworm, up to 25 m in length)

    • Taenia solium (the pork tapeworm, 7 m)

    • Diphyllobothrium latum (the fish tapeworm, 10 m)

  • The small tapeworms are

    • Hymenolepis nana (the dwarf tapeworm, 25–40 mm)

    • Hymenolepis diminuta (the rodent tapeworm, 20–60 cm)

    • Dipylidium caninum (the dog tapeworm, 10–70 cm)

  • Humans are the only definitive host of T saginata and T solium

  • Humans are infected by eating raw or undercooked infected beef

  • An adult tapeworm consists of a head (scolex), a neck, and a chain of individual segments (proglottids) in which eggs form in mature segments

Demographics

  • Infection most common in cattle breeding area

  • Gravid segments of T saginata are passed in human feces to soil, where they are ingested by grazing animals, especially cattle

  • The eggs then hatch to release embryos that encyst in muscle as cysticerci

Clinical Findings

Symptoms and Signs

  • Most infected persons are asymptomatic

  • Abdominal pain and other gastrointestinal symptoms may be present

Differential Diagnosis

  • Pork, fish, dwarf, rodent, or dog tapeworms

  • Chronic fatigue syndrome

  • Chronic hepatitis

  • Irritable bowel syndrome

  • Amebiasis

  • Ascariasis

  • Enterobiasis (pinworm, mostly children)

  • Hookworm disease

  • Strongyloidiasis

  • Celiac sprue or tropical sprue

  • Pernicious anemia (D latum)

Diagnosis

Laboratory Tests

  • Complete blood count; eosinophilia is common

Diagnostic Procedures

  • Infection is often discovered by finding passage of proglottids in stool

Treatment

Medications

  • Praziquantel

    • Treatment of choice

    • Single dose of 5–10 mg/kg orally is highly effective

    • Side effects include headache, malaise, dizziness, abdominal pain, nausea

  • Niclosamide

    • Alternative therapy

    • Single dose (2 g for adults, chewed) is effective

    • Side effects include nausea, malaise, abdominal pain

Outcome

Prognosis

  • Excellent with therapy

When to Refer

  • For assistance in making the diagnosis

  • Inability to clear the infection

Prevention

  • Cysticercus bovis is killed by cooking at 56°C or freezing at –10°C for 5 days

  • Pickling is not adequate

Reference

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Craig  P,  et al. Intestinal cestodes. Curr Opin Infect Dis. 2007 Oct;20(5):524–32.
[PubMed: 17762788]  

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