Diphyllobothrium latum


D. latum life cycle (Courtesy of CDC)
D. latum proglottids
Diphyllobothrium latum
  • A type of tapeworm infection
  • D. latum and D. nihonkaiense are most common pathogens[1]
    • 15-45 day latency period
  • Found mostly in cold waters Palaearctic region and North America[1]
    • Generally due to eating raw or undercooked fish.
    • In US, Great Lakes and Alaska are most common locations.

Clinical Features

  • Usually asymptomatic or mild GI symptoms[1]
    • 20% of cases report diarrhea, abdominal pain or discomfort
  • Rarely, migrating proglottids can cause cholangitis, cholecystitis, or intestinal obstruction
  • Competes for absorption of vitamin B12 → can cause pernicious anemia

Differential Diagnosis

Helminth infections

Cestodes (Tapeworms)

Trematodes (Flukes)

Nematodes (Roundworms)


Abdominal CT showing multiple reactive mesenteric lymph nodes (arrows) in a patient with diphyllobothrium latum infection.
  • Stool sample - morphologic identification of eggs[1]
    • Molecular (PCR) diagnosis also possible, but less used



  • Discharge

See Also

External Links


  1. 1.0 1.1 1.2 1.3 1.4 Scholz T, Garcia HH, Kuchta R, Wicht B. Update on the Human Broad Tapeworm (Genus Diphyllobothrium), Including Clinical Relevance. Clinical Microbiology Reviews. 2009;22(1):146-160. doi:10.1128/CMR.00033-08.