Opisthorchis spp

From Dog
Adult O. felineus[1]

Parametorchis spp are a parasitic trematode of dogs in Asia and Africa.

Species which are pathogenic to dogs include:

  • Opisthorchis tenuicollis
  • Opisthorchis felineus[2]
  • Opisthorchis viverrini[3]

These trematodes rely on two intermediate hosts (snails and marine fish[4]). These flukes can survive within the dog for up to 10 years[5].

Metacercaria are ingested by dogs, which migrate up the bile and pancreatic ducts, where they lay eggs[6].

Clinical signs in dogs are usually absent but mild symptoms relating to unthriftiness include lethargy, diarrhea, ocular and nasal discharges. Migration of immature flukes can cause acute hepatitis and pancreatitis.

Hematological changes include increased activity of glutamate dehydrogenase[7].

Diagnosis is based on identification of eggs in feces using ethyl acetate sedimentation[8].

A differential diagnosis would include other hepatic and bile duct flukes such as Parametorchis complexus, Metorchis spp and Clonorchis spp.

Treatment is effective with praziquantel[9].


  1. Medical Parasitology
  2. Schuster RK et al (2007) Liver flukes in dogs and treatment with praziquantel. Vet Parasitol 150(4):362-365
  3. Aunpromma S et al (2012) High prevalence of Opisthorchis viverrini infection in reservoir hosts in four districts of Khon Kaen Province, an opisthorchiasis endemic area of Thailand. Parasitol Int 61(1):60-64
  4. Cribb TH et al (1999) Faustulid trematodes (Digenea) from marine fishes of Australia. Syst Parasitol 44(2):119-138
  5. Harinasuta C & Harinasuta T (1984) Opisthorchis viverrini: life cycle, intermediate hosts, transmission to man and geographical distribution in Thailand. Arzneimittelforschung 34(9B):1164-1167
  6. Bowman, DD (2009) Georgis' parasitology for veterinarians. Elsevier Saunders, Missouri. pp:125-126
  7. Schuster RK et al (2007) Liver flukes in dogs and treatment with praziquantel. Vet Parasitol 150(4):362-365
  8. Okaeme AN (1985) Zoonotic helminths of dogs and cats at New Bussa, Kainji Lake area, Nigeria. Int J Zoonoses 12(3):238-240
  9. Kotel'nikov GA & Varenichev AA (1988) The search for effective anthelmintics in opisthorchiasis in domestic carnivores--definitive Opisthorchis hosts. Med Parazitol (Mosk) 2:24-26