Page 153 - Medical Parasitology_ A Textbook ( PDFDrive )

146 12 Trematodes: Flukes

Pathogenesis and Clinical Features
Fasciola hepatica causes mechanical damage due to its large size. It causes paren-
chymal injury while passing through the liver tissues. Humans develop severe
inflammatory response as they are not its primary host. During larval migration,
patients may present with fever, right upper quadrant pain, eosinophilia and hepato-
megaly. The symptoms subside as parasites reach the liver. In chronic infection,
patients may present with biliary obstruction, cholelithiasis, obstructive jaundice,
biliary cirrhosis and anaemia. Its larvae may undergo ectopic migration and pene-
trate through the diaphragm to reach the lung. Other ectopic sites include subcuta-
neous tissue, genitourinary tract and brain.

Diagnosis
1. Microscopic examination
Demonstration of eggs in faeces or aspirated bile.
2. Serodiagnosis
3. Imaging
Ultrasound and CT abdomen.

Treatment
Triclabendazole (single oral dose of 10 mg/kg) is the treatment of choice. Bithionol
is an alternative drug.

Prevention and Control
1. Prevent pollution of water courses with sheep and cattle faeces
2. Proper sanitation
3. Wash watercresses and other water vegetations, preferably in hot water or cook
well before consumption

Intestinal Flukes

Fasciolopsis buski

Common name Giant intestinal fluke

Distribution
It is a common parasite of humans and pigs in China and in Southeast Asian countries.

Habitat
The adult worm lives in the duodenum or jejunum of pigs and humans.

Morphology
The adult is a large fleshy worm, 20–75 mm long, 8–20 mm broad and 0.5–3 mm in
thickness. It is elongated, ovoid in shape, with a small oral sucker and a large ace-
tabulum. The adult worm has a lifespan of about 6 months.