Introduction to Trematodes (Flukes)

Flukes are obligate parasitic flatworms that infect the blood vessels, gastrointestinal tract, lungs, or liver. They typically have complex life cycles requiring the involvement of at least 2 hosts. They are often categorized according to the principal organ system they invade:

• Clonorchis sinensis, Fasciola hepatica, and Opisthorchis species: Liver and bile ducts

• Fasciolopsis buski, Heterophyes heterophyes, and related organisms: Lumen of the gastrointestinal tract

• Paragonimus westermani and related species: Lungs

• Schistosoma species: Vasculature of the gastrointestinal or genitourinary system