Diphyllobothriasis (Fish Tapeworm Infection)

Excerpt

Diphyllobothriasis is a parasitic infection caused by broad or fish tapeworms. Attention to diphyllobothriasis has grown recently due to increasing numbers of case reports in nonendemic areas and improved understanding of the pathogen from studies that use molecular techniques. Most species causing human infection have recently been reclassified and renamed based on morphological and molecular analyses.[CDC. Diphyllosbothriasis. 2019]

Commonly known as broad or fish tapeworms, diphyllobothriids have the dubious distinction of being the longest intestinal zoonotic parasites to infect humans. After a mammal or bird ingests fish that harbor infectious larvae of the family Diphyllobothriidae, broad tapeworms mature in the intestines of their hosts. Human infections are usually mild or asymptomatic, often noticed only when the mature worm is passed in feces. Symptoms may include diarrhea, abdominal pain or discomfort, constipation, fatigue, the passage of proglottids, headache, and allergic reactions. The condition commonly causes B₁₂ deficiency, but anemia is uncommon. Diphyllobothriids may rarely obstruct lumina, leading to cholangitis, intestinal obstruction, appendicitis, and cholecystitis.