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Fasciola hepatica (liver fluke)
Epidemiology:
1) distribution: may parts of the world
2) animal hosts: cattle, sheep, goats, other herbivores
3) intermediate host: snail
a) cercaria shed from snails encyst on aquatic vegetation
b) infectious metacercariae present on aquatic vegetation
4) humans most often acquire infection by eating watercress
5) infection may occur by eating infected cattle or sheep liver
Pathology:
1) ingested larvae penetrate intestinal wall
2) larvae migrate through peritoneal cavity to the liver
3) they burrow through the capsule & parenchyma to become adults in the bile ducts
4) egg-laying is initiated in about 2 months
5) migration of the larvae through the liver elicits a painful inflammatory reaction
6) bile ducts eventually become fibrotic
Clinical manifestations:
1) colic
2) jaundice
3) abdominal pain & tenderness
4) cholelithiasis
5) fever
6) nausea
7) diarrhea
9) cough
10) urticaria
Laboratory:
1) complete blood count: eosinophilia
2) liver function tests
- abnormal liver function tests (LFTs)
- increased conjugated bilirubin
3) diagnosis made by finding unembryonated eggs in feces
a) yellowish-brown, operculate eggs
b) 130-150 by 63-90 um
c) not easily distinguish from eggs of Fasciolopsis
4) Fasciola hepatica serology
Management:
1) bithionol 30-50 mg/kg on alternate days for 10-15 doses
2) albendazole may be useful
3) praziquantel is not very effective
Related
albendazole (Albenza)
bithionol (Bithin)
Clonorchis sinensis (Oriental liver fluke)
Fasciola hepatica antibody in serum
General
Fasciola
Properties
KINGDOM: animal
PHYLUM: helminth
References
- Clinical Diagnosis & Management by Laboratory Methods,
19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia,
PA. 1996, pg 1290
- Harrison's Principles of Internal Medicine, 13th ed.
Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 930