Clonorchis sinensis, commonly known as the oriental liver fluke, is a parasite that infects the livers of humans. It is found primarily in Asia, where an estimated 30 million people are currently infected. People become infected by eating raw or undercooked freshwater fish that contain the parasite's larvae. The larvae hatch in the intestines and migrate to the bile ducts of the liver where they mature into adult flukes. Long-term infection can lead to liver inflammation, enlargement, and over time cirrhosis or cholangiocarcinoma if left untreated. Praziquantel is the drug of choice for treating infections.

1. Clonorchis sinensis
 Kingdom : Animalia
 Phylum : Platyhelminthes
 Class : Trematoda
 Order : Opisthorchiida
 Family : Opisthorchiidae
 Genus : Clonorchis
 Species : C. sinensis

2. Brief Introduction to C. sinensis
 “Oriental Liver Fluke”. Food born parasite
 601 million people are currently at risk, 570 million of
which live in China and Taiwan.
 An estimated 30 million people are infected with C.sinensis.
 The parasite may live up to 45 years in humans.

3. Epidemiology
 Geographical distribution:
 Asia only
 Mainland China, highly endemic in south eastern China,
Japan , Taiwan, Korea, Vietnam and eastern part of Russia
 Reports outside of Asia are important (imported cases)

4. Epi cont……
 Clonorchiasis is endemic where there is poor sanitation.
 The right snail host.
 The right fish (cyprinoid fish) as the second intermediate
host.
 A population who eats raw, poorly pickled, smoked, dried
or salted freshwater fish.

5. Geographic Distribution
• Japan
• Korea
• China
• Taiwan
• Vietnam

6. Hosts
Definitive
• Fish eating mammals
• Humans are the principal definitive host, but
dogs and other fish-eating canines act as
reservoir hosts.
Intermediate Hosts
• Snails(1st)- Parafossarulus manchouricus
• Fish(2nd)- 12 species of fish are capable of
passing the infection to human.

7. Transmission route
 Source of infection: patients, infected reservoir hosts: cats,
dogs, mice, pigs
 The infection is acquired by eating raw or inadequately
cooked freshwater fish or shrimp which are previously
infected.
 Susceptibility: human is generally susceptive, related with
the dietary habits

8. Life cycle

9. Pathogenesis
 Worms mechanical stimulation proliferate inflammatory
reaction in the biliary epithelium.
 The wall of the bile ducts thickened ,fibrous tissue around
the bile duct, and worm obstruction cause cholestasis.
 When bacteria infection occur, cause cholecystitis,
cholangeitis, sometimes cholelithiasis happens.

10. Pathology
 Intrahepatic bile ducts expansion, hepatomegaly, necrosis
of liver tissue
 Continuous severe infection may cause liver cirrhosis.
 Persistent Cholestasis cause biliary liver cirrhosis.
 Associate with cholangiocarcinoma and hepatic
carcinoma.

11. Clinical Manifestation
 Incubation period: 1-2 months
 In mild clonorchis sinensis infections are asymptomatic, only
eggs are found in the feces
 Acute symptoms appear in heavy infection: chill, high fever,
slight jaundice, hepatomegaly, eosinophilia, other patients
have splenomegaly, and chronic stage develops.
 Continuous re-infection: cirrhosis and portal hypertension. It
may cause stunted growth in children .

12. Diagnosis
 Patient History:
 Living in or come from the endemic area.
 Eating raw or inadequately cooked
freshwater fish and shrimp
 Clinical sign:
 Gastrointestinal symptoms, hepatomegaly,
neurasthenia, cholangoitis, cholecystitis, etc.

13. Diagnosis
 Laboratory findings:
Discovery of characteristic eggs in faeces or aspirated bile.
 Several serological tests.
 Intradermal allergic tests.
 Blood routine test: eosinophilia, anaemia in severe
infection.

14. Prevention and control
Cut off the route of transmission:
 Avoid eating inadequately cooked freshwater fish and
shrimp
 Sanitary disposal of the excreta
 Avoid of drinking contaminated water
 Control of snails.

15. Treatment
 Treat the patients and domestic animal(cats and dogs, etc.)
at the same time.
 Drugs:
 Praziquantel (most effective)
 Albendazole
 Surgical intervention may become necessary in cases with
obstructive jaundice.

16. Beware!!!
 Metacercariae can remain viable even after the fish has
been pickled, salted, dried, or smoked.