Hepatobiliary fascioliasis: A neglected re-emerging threat, its diagnostic and management challenges

Figure 1 Life cycle of Fasciola spp. Immature eggs are discharged in the biliary ducts and passed in the stool (1). Eggs become embryonated in freshwater over approximately 2 weeks (2); embryonated eggs release miracidia (3), which invade a suitable snail intermediate host (4). In the snail, the parasites undergo several developmental stages (sporocysts 4a, rediae 4b, and cercariae 4c). The cercariae are released from the snail (5) and encyst as metacercariae on aquatic vegetation or other substrates. Humans and other mammals become infected by ingesting metacercariae-contaminated vegetation (e.g., watercress) (6). After ingestion, the metacercariae excyst in the duodenum (7) and penetrate through the intestinal wall into the peritoneal cavity. The immature flukes then migrate through the liver parenchyma into biliary ducts, where they mature into adult flukes and produce eggs (8). In humans, maturation from metacercariae into adult flukes usually takes about 3-4 months; development of F. gigantica may take somewhat longer than F. hepatica. Source: CDC-DPDx-Fascioliasis[12].

Figure 2 The termite's analogy illustration. We suggest calling the liver flukes the liver “termites” emphasizing the inhabitation and damage to the biliary tract and hepatic parenchyma.

Figure 3  Flowchart of mechanisms of liver and bile duct involvement and how they lead to symptoms.

Figure 4  Viable Fasciola spp. Specimens retrieved from the gallbladder during endoscopic retrograde cholangiopancreatography.