Sheep Liver Fluke Quiz

F. gigantica (Giant Liver Fluke)

• Common name: Sheep Liver Fluke or Giant Liver Fluke
• Hosts: Sheep, local cattle, herbivores
• 1st intermediate host (IH): Snails (Lymnaea philippinensis, Lymnaea auricularia rubiginosa)
• 2nd IH: Kangkong (Ipomoea obscura) and Water Cress (Nasturtium officinale)
• Habitat: Liver parenchyma, gall bladder
• Infective stage: Metacercaria
• Pathology: Fascioliasis or Liver Rot, Liver Atrophy, Halzoun
• Laboratory diagnosis: Stool exam, liver biopsy, PCR
• Drug of choice: Bithionol, Triclabendazole

Morphology

• Adult fluke: large, broad, and flat body (20-50 mm in length, 6-12 mm in width)
• Cephalic cone prominent
• Highly branched testis and dendritic ovary
• F. gigantica egg: large, ovoidal, operculated, and yellowish to brownish in color

Pathology

• Acute or invasive phase: asymptomatic or produces fever, abdominal pain, and hypereosinophilia
• Chronic phase: diagnosed through surgical operation, parasites reach bile ducts, and cause obstruction, inflammation, and fibrosis
• Small protuberance at the abopercular end

Diagnosis and Prevention

• Diagnosis: Stool exam, serologic tests (ELISA, EIA), molecular method (PCR)
• Prevention and control: Health education, proper waste disposal, proper food preparation, fish irradiation at a dose of 0.15 kGy

F. lanceolata (Lancet Fluke)

• Common name: Lancet Fluke
• Hosts: Sheep, cattle
• 1st IH: Cionella lubrica, Helicella candibula (snail)
• 2nd IH: Formica fusca (ant)
• Habitat: Biliary tree of herbivores
• Morphology: Blade-like, lancet-like shaped, aspinous body, large ventral sucking disc
• Laboratory diagnosis: Stool exam (eggs)

E. pancreaticum (Pancreatic Fluke)

• Common name: Pancreatic Fluke
• Hosts: Hogs (pancreatic ducts), sheep, cattle (biliary ducts)
• 1st IH: Bradbybaena similaris, Macrochlamys indica
• 2nd IH: Technomyrmex deterquens (ant)
• Habitat: Pancreas, duodenum, biliary duct
• Morphology: Larger oral sucker, 2 notched testes, 1 notched ovary
• Laboratory diagnosis: Stool exam (eggs)

P. westermani (Lung Fluke)

• Egg: oval, yellowish-brown, thick-shelled, and has a flattened but prominent operculum
• Pathology:
  • I. Granulomatous formation in the lungs, fibrotic encapsulation, dry cough, chest pains, dyspnea, hemoptysis
  • II. Erratic paragonimiasis: worm migration in the abdominal wall, lymph nodes, omentum, pericardium, myocardium, intestinal wall, and brain → Cerebral paragonimiasis
• Diagnosis: Radiography (X-ray), sputum examination (definitive diagnosis, 3% NaOH), intradermal test, serologic test (CF, EIA, etc.)

Schistosoma spp. (Blood Flukes)

• Dioecious, presence of gynecophoral canal or groove
• In perpetual copulation
• Ova is non-operculated
• Infective stage: cercaria
• Species:
  • Schistosoma japonicum
  • Schistosoma mansoni
  • Schistosoma haematobium
  • Schistosoma mekongi
  • Schistosoma intercalatum

Pathology

• I. Early Schistosomiasis: itching, chills, and fever
• II. Colonic Schistosomiasis: deposition of eggs in the colon (dysentery or diarrhea)
• III. Hepatosplenic Schistosomiasis: most serious consequence, characterized by hepatosplenomegaly and ascites
• IV. Pulmonary Schistosomiasis: larval migration to the lungs
• V. Cerebral Schistosomiasis: meningoencephalitis, headache, confusion, lethargy, and coma

Diagnosis

• 1. Stool exam
• 2. Immunodiagnosis:
  • A. Intradermal test
  • B. IHA
  • C. Merthiolate Iodine Formalin Ether Concentration Technique (MIFECT/MIFCT)

Flotation Techniques

• Principle: parasites are less dense than the solutions used and during centrifugation, they float to the surface
• Reagents: zinc sulfate, magnesium sulfate, brine, sugar
• Methods:
  • Brine Flotation Method (by Willis)
  • Zinc Sulfate Flotation Technique
  • Sheather’s Sugar Flotation Technique