Metorchis spp

From Dog
Adult M. conjunctus[1]

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

Species which are pathogenic to dogs include:

  • Metorchis bilis
  • Metorchis conjunctus[2]

These trematodes rely on two intermediate hosts (snails and marine fish[3]). These flukes can survive within the dog for up to 10 years[4].

Metacercaria are ingested by dogs, which migrate up the bile and pancreatic ducts, where they lay eggs[5].

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[6].

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, Opisthorchis felineus and Clonorchis spp.

Treatment is effective with praziquantel[9].


  1. Stanford University
  2. Unruh DH et al (1973) Parasites of dogs from Indian settlements in northwestern Canada: a survey with public health implications. Can J Comp Med 37(1):25-32
  3. Cribb TH et al (1999) Faustulid trematodes (Digenea) from marine fishes of Australia. Syst Parasitol 44(2):119-138
  4. Harinasuta C & Harinasuta T (1984) Opisthorchis viverrini: life cycle, intermediate hosts, transmission to man and geographical distribution in Thailand. Arzneimittelforschung 34(9B):1164-1167
  5. Bowman, DD (2009) Georgis' parasitology for veterinarians. Elsevier Saunders, Missouri. pp:125-126
  6. Mills JH & Hirth RS (1968) Lesions caused by the hepatic trematode, Metorchis conjunctus, Cobbold, 1860. A comparative study in carnivora. J Small Anim Pract 9(1):1-6
  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. Schuster RK et al (2007) Liver flukes in dogs and treatment with praziquantel. Vet Parasitol 150(4):362-365