Clonorchis sinensis

• Clonorchis sinensis

  • Common Name: Chinese Liver Fluke
  • Disease: Clonorchiasis
  • Habitat: Liver, Bile duct
  • Final Host: Humans, Carnivorous mammals
  • Intermediate Hosts:
  • 1st IH: Freshwater snails (Alocinma, Bulinus, Parafossarulus, Semisulcospira, Melanoides)
  • 2nd IH: Freshwater fish (Cyprinidae family)
  • Diagnostic Stage: Embryonated eggs in feces
  • Infective Stage: Metacercaria
  • MOT: Ingestion of undercooked fish contaminated with encysted metacercariae
  • DOC: Praziquantel, Albendazole
• Egg Characteristics of C. sinensis

  • Size: 30 µm × 15 µm
  • Shape: Resembles an "old-fashioned lightbulb"
  • Features:
  • Embryonated with developed miracidium
  • Wide operculum with opercular shoulders
  • Abopercular/terminal knob
• Larval Characteristics of C. sinensis

  • Miracidium → Cercaria stages show typical fluke larvae traits
  • Cercaria: Has a tail, which is lost upon penetration of the host
• Adult Characteristics of C. sinensis

  • Shape: Flat, fleshy
  • Anterior & posterior portions narrower than midbody
  • Anterior end: Tapering
  • Posterior end: Rounded
  • Oral sucker: Large, bigger than ventral sucker
  • Testes: 2 deeply branched
• Clinical Manifestations of C. sinensis


  Asymptomatic Infections

  • Occurs in light infections
  • No obvious symptoms

  Clonorchiasis (Heavy Infections)

  • Symptoms:
  • Fever
  • Abdominal pain
  • Eosinophilia
  • Anorexia
  • Diarrhea
  • Epigastric discomfort
  • Occasional jaundice

  
  

  • Severe Cases:
  • Enlarged, tender liver
  • Some may develop leukocytosis
  • Chronic infections → Liver dysfunction
• Laboratory Diagnosis C. sinensis

  • Eggs of Clonorchis, Metagonimus, and Heterophyes are almost indistinguishable
  • Differentiation is based on recovery of adult worm
  • Egg identification: Report as "presence of heterophyd egg"
• Prevention & Control

  • Proper sanitation
  • Avoid eating raw, undercooked, or freshly pickled freshwater fish & shrimp
• Image of C. sinensis


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