| Additional Info: |
The eggs of Fasciola hepatica are operculated (have a hatch-like structure) and average 140 μm in length.
Transmission occurs through the ingestion of raw, fresh-water vegetation which contain the encysted flukes. The plants become exposed when the water they are growing in becomes contaminated by eggs in the fecal matter of an infected sheep or cow. Nearly all cases are a result of watercress consumption, although alfalfa and water lettuce play a large role is some areas.
The adult flukes have large suckers that allow them to attach to the wall of the extrahepatic (or sometimes) intrahepatic bile ducts. The symptoms of chronic infection include biliary colic, abdominal pain, and sometime jaundice. These symptoms reflect the biliary obstruction and inflammation caused by the presence of the large adult worms. Chronic Fasciola infection can cause stricture and is a risk factor for cholangiocarcinoma.
Random note: Fasciola eggs have been isolated from Egyptian mummies!
DDx: Paragonimus westermanii (not operculated) and Clonorchis-Opisthorchis (much smaller)
|