Hepatic Clonorchis & Opistorchis

• Hepatic flukes


  • Fasciola hepatica
  • Fasciola gigantica
  • Clonorchis sinensis
  • Opisthorchis felineus
  • Opisthorchis viverrini
• Life cycle of Clonorchis

  1. Adult worm in biliary duct lays eggs in bile duct, eggs discharged in duodenum and feces

  2. Embryonated ova ingested by snail host

  3. Miracidium infects snail, develops into sporocyst, rediae, cercariae

  4. Cercariae encyst as metacercariae in freshwater fish

  5. Humans ingest metacercariae in raw fish

  
• Clonorchis cercariae


  • Lophocercous (long-tailed)
• Life cycle of Opisthorchis


  1. Adult worm in bile duct, eggs discharged in feces

  2. Embryonated ova ingested by snail host

  3. Miracidium infects snail, develops into sporocyst, rediae, cercariae

  4. Cercariae encyst as metacercariae in freshwater fish

  5. Humans ingest metacercariae in raw fish

  
• Opisthorchis cercariae


  • Pleurolophocercous (fin-tailed)
• Infective stages


  • Embryonated ovum (to snail)
  • Metacercariae (to humans)
• Diagnostic stage


  • Embryonated ovum
• Definitive host


  • Humans
• First intermediate host


  • Snail
• Second intermediate host


  • Freshwater fish
• Clonorchis adult worm


  • 10-25mm long, 3-5mm wide
  • Oral sucker
  • Pharynx
  • Unbranched intestine
  • Vitellaria in middle 1/3 of body
  • Lobed ovary
  • Branched testes
  • Uterus
• Opisthorchis adult worm


  • 8-12mm long, 1.5-3mm wide
  • Oral sucker
  • Pharynx
  • Unbranched intestine
  • Vitellaria in middle 1/3 of body
  • Lobed ovary
  • Lobed testes
  • Uterus

  
• Clonorchis vs Opisthorchis


  • Share same morphology except testes (Clonorchis branched, Opisthorchis lobed)
  • Clonorchis vitellaria finely granular, Opisthorchis vitellaria not
• Opisthorchis species


  • Opisthorchis viverrini (Southeast Asia)
  • Opisthorchis felineus (Eastern Europe, Siberia, EU)
• Clonorchis and Opisthorchis ova

  • Yellowish-brown, broadly ovoid
  • Operculum fits into thickened rim of eggshell (shoulder)
  • Small protuberance at posterior end
  • Fully embryonated when laid
• First intermediate hosts


  • Clonorchis: Parafossarulus, Bulimus
  • Opisthorchis: Bithynia
• Second intermediate hosts


  • Cyprinidae family of freshwater fish
• Light Opisthorchiasis/Clonorchiasis infection


  • Asymptomatic or symptomatic (fatigue, weakness, altered appetite, diarrhea, weight loss, abdominal pain, enlarged liver)
• Heavy Opisthorchiasis/Clonorchiasis infection


  • Bile duct obstruction by adult worms, causing gallstone formation
  • Adult worms entering gallbladder can cause cholecystitis and cholelithiasis
• Chronic Opisthorchiasis/Clonorchiasis


  • Fibrosis of liver and bile ducts due to inflammatory and proliferative changes
  • Pancreatitis in Clonorchiasis from worm invasion of pancreatic duct
  • Increased risk of gallstones in diabetic patients with chronic Opisthorchiasis
• Presence of worms in bile duct can trigger proliferative changes and fibrosis
• Cholangiocarcinoma


  • Clonorchis and Opisthorchis produce carcinogenic nitroso compounds
  • Can cause adenocarcinoma of bile ducts and gallbladder
• No ectopic infection in Clonorchiasis and Opisthorchiasis
• Trematodes that can cause ectopic infections

  • Paragonimus
  • Schistosoma
  • Fasciola
• Treatment


  • Praziquantel
  • Praziquantel-Albendazole
• Prevention


  • Chemotherapy
  • Health education
  • Eating sufficiently cooked fish
  • Salt treatment with 3-6% acetic acid
  • Freezing
  • Proper human waste disposal