1) Clonorchis sinensis is a food-borne trematode parasite known as the oriental liver fluke. It infects over 30 million people in Asia, mainly in China and Taiwan. 2) It has a complex life cycle involving freshwater snails and fish as intermediate hosts. Humans become infected by eating raw or undercooked freshwater fish containing the infective metacercariae. 3) Most infections are asymptomatic but can cause liver inflammation and damage. Heavy infections may lead to complications like cholangitis, cholecystitis and liver cirrhosis. Diagnosis involves finding characteristic eggs in stool or bile. Praziquantel treatment is highly effective.

1. GHODIWALA TOSSIF
ML610
MOSCOW 2013
Clonorchis Sinensis

3. Taxonomy
Kingdom : Animalia
Phylum : Platyhelminthes
Class : Trematoda
Order : Opisthorchiida
Family : Opisthorchiidae
Genus : Clonorchis
Species : C. sinensis
*A quick note – Clonorchis sinensis was given its own genus by Looss
because of the parasites branched testes as apposed to the
Opisthorchis lobed testes

4. 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 in humans.

6. Etiology
Morphology
Adult worm
Flat, elongated worm, with the size 10-15×3-5 mm
They are monocious, with two suckers
The most characteristic feature is branched testis in the posterior third
of the body, and relative small ovary before them

8. Morphology (eggs)
Small, 26-30 x 15-17 um
Ovoid, yellowish color
Operculated at one end, small knob at opposite end

10. Metacercariae of Clonorchis sinensis collected from digested fish. The cyst
wall is elliptical 0.16-0.20 mm long. Dark granules are in the bladder.

11. Epidemiology
Geography:
Asia only
Mainland China, highly endemic in southeastern China
Taiwan, Korea, Vietnam and eastern part of Russia
Reports outside of Asia are important (imported cases)

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

14. Geographic Distribution
Japan
Korea
China
Taiwan
Vietnam

15. Definitive Hosts
Any fish eating mammals
Humans
Humans are an incidental host, the natural definitive hosts are
those that fallow in this list
Pigs
Dogs
Cats
Rats
Camels

16. Intermediate Hosts
Snails
Fish
First intermediate host must always be a snail, mainly
Parafossarulus manchouricus
Second intermediate host is usually a fish
12 species of fish are mainly responsible for passing the
infection to humans

17. Source of infection: patients, infected reservior hosts:cats,
dogs, mice, pigs
Route of transmission: 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

18. Life Cycle

20. Life Cycle
 Adults in biliary ducts, embryonated eggs pass to intestine and out with the
feces
 Eggs reach water, ingested by suitable snail (P. manchouricus)
 In the snail (first intermediate host, eggs release miracidium and goes through
several stages in host (sporocyst>rediae>cercariae)
 Cercariae released from snail, free-swimming in water, penetrates under scales
of an appropriate freshwater fish (second intermediate host)
 Metacercariae encyst in the fish muscle
 Humans infected by eating raw, partially cooked, smoked or pickled fish
 Metacercariae excysts in the duodenum
 Ascends up through intestine to bile ducts
 Matures to adult in 30 days
 Worms may live 30-40 years in final host
 Carnivorous animals can serve as reservoir hosts

21. Critical Thinking
The asexual reproduction of C. sinensis enables an exponential
multiplication of cercaria individuals from one miracidium.
How can this aid C. sinensis?
- This aids the Clonorchis in reproduction, because it enables
the miracidium to captilatize on one chance occasion of
passively being eaten by a snail before the egg dies.

22. Question
Why would the cercariae want to encyst themselves in the
flesh/skin of the second intermediate host?
- The metacercarial cysts are acid-resistant, thus ensuring that
they are protected from the acidic environment of the
stomach after ingestion

23. 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

24. 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

26. Clinical Manifestation
Incubation period: 1-2 months
Most person with mild
clonorchis sinensis infections are
asymptomatic, only eggs can be
found in the feces

27. Clinical Manifestation
Acute symptoms appear when the primary infection is
heavy: sudden onset, chill, high fever, slight jaundice,
hepatomegaly, eosinophilia, a few patients have
splenomegaly, and weeks later, enter chronic stage
Continuous reinfection: cirrhosis and portal
hypertension. In children may cause malnutrition
growth development disturbance, even dwarf

29. Complications
Acute or chronic cholecystitis, cholangeitis and cholelithiasis
are the most common complications
Portal liver cirrhosis: portal hepertension result in upper
gastrointestinal bleeding
Cholestatic cirrhosis
Pancreatitis
Primary carcinoma of the liver and cholangiocarcinoma

33. Diagnosis
Epidemiologic date:
living in or come from the endemic area
The history of eating raw or inadequately cooked freshwater fish and
shrimp
Clinical date:
gastrointestinal symptoms, hepatomegaly, neurasthenia,
cholangoitis, cholecystitis, etc.
Laboratory findings:
Discovery of characteristic eggs in feces or by duodenal aspiration
come to accurate diagnosis
Eosinophilia and positive immunologic test support the diagnosis

34. Laboratory Findings
Blood routine test: eosinophilia, anemia in severe infection
Eggs examination:
simple smear feces to find eggs
Stool concentration technique may increase the positive rate
Duodenal aspiration: raise the chance of finding eggs

35. Laboratory Findings
Immunological Test
Skin test: positive rate 97.9%, 99.5% coincide with the
result of the feces
PHA: positive rate 53.7%, 80% coincide with the result of
the feces
ELISA: positive rate 98.3%, 93.5% coincide with the result
of the feces

36. Differential Diagnosis
Viral hepatitis
Liver cirrhosis of other origins
Primary carcinoma of the liver
Fasciolopsiasis
Other specie of flukes infection

37. Treatment
Drugs:
Praziquantel (most effective)
Albendazole

38. Pathogenic Treatment
Praziquantel is the best choice of drug for the therapy
Dose: 15-25mg/kg, three times a day, for 2 days, the total dose
is 90-150mg/kg
Another choice of drug is Albendazole
Heteropathy Treatment

40. Prognosis
Good of the mild infection
Co-infection with viral hepatitis may make the disease severe

41. Prevention
Control of the source of infection:
Treat the patients and domestic animal(cats and dogs, etc.)
at the same time.
Cut off the route of transmission:
Avoid of eating inadequately cooked freshwater fish and
shrimp
Sanitary disposal of the excreta
Avoid of drinking raw water

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

43. reference:
http://www.phac-aspc.gc.ca/msds-ftss/msds34e.html
http://animaldiversity.ummz.umich.edu/site/accounts
/information/Clonorchis_sinensis.html
http://www.k-
state.edu/parasitology/625tutorials/Clonor02.html
http://www.k-
state.edu/parasitology/625tutorials/Trematodes08.htm
l
http://en.wikipedia.org/wiki/Clonorchis_sinensis