Opisthorchis viverrini

Background

• a.k.a. "southeast asian liver fluke" (endemic)
• Trematode
• Also within genus: opisthorchis felineus (Europe/Asia incl Russia)

Life Cycle

• Eggs pass in feces --> freshwater snail ingestion --> larval trematode embeds in fish skin/flesh --> Fish consumed raw --> duodenal cyst and subsequent biliary infection
• Fluke count may effect clinical presentation (lower counts more asymptomatic)

Risk Factors

• Exposure to endemic areas (see above)
• Consumption of raw/undercooked fish

Clinical significance

• May have acute infectious phase
• Source of mild and moderate GI disease
• Chronic infection predisposes to cholangitis, cholcystitis, cholangiocarcinoma (rare)

Clinical Presentation

• Mild: dyspepsia, diarrhea, abdominal pain, constipation
• Moderate: hepatomegaly, malnutrition
• Felineus species may have an acute phase: alike to schistosomiasis (fever, facial edema, lymphadenopathy, arthralgias, rash, and eosinophilia) and involvement may extend to pancreatic duct in chronic cases

Differential Diagnosis

Helminth infections

Cestodes (Tapeworms)

• Taenia saginata
• Taenia solium (Cysticercosis)
• Diphyllobothrium latum
• Hymenolepis nana
• Echinococcus granulosus

Trematodes (Flukes)

• Fasciola hepatica
• Fasciolopsis buski
• Opistorchis viverrini
• Schistosoma spp
  • Schistosomiasis
• Chlonorchis sinensis
• Paragonimus spp.

Nematodes (Roundworms)

• Ascaris lumbricoides
• Enterobius vermicularis (Pinworm)
• Filarial worms
  • Loa Loa
  • Onchocerciasis
  • Lymphatic filariasis (Elephantiasis)
    • Wuchereria bancrofti
    • Brugia malayi
    • Brugia timori
• Hookworm
  • Necator americanus
  • Ancylostoma duodenale
  • Cutaneous larva migrans (Ancylostoma braziliense)
• Dracunculiasis
• Strongyloides stercoralis
• Trichuris trichiura (Whipworm)
• Anisakis
• Toxocara spp.
• Trichinosis

Management

• Praziquantel, 75mg/kg/day orally for 2 days (adults/pediatric) with meal

or

• Albendazole, 10mg/kg/day orally for 7 days (adults/pediatric) with meal [non-FDA alternative]

• Identical to treatment for Clonorchis
• In cases of clonorchis in China, Trebindamine 400 mg once has less side effects and equal efficacy (not available in U.S.)

See Also

• Helminth infections