Clonorchis sinensis

1
Clonorchis sinensis

• by
• Albert Teo
• Doug Mandler

2
Taxonomy

• Kingdom AnimaliaPhylum PlatyhelminthesCla
  ss TrematodaOrder OpisthorchiidaFamily
  OpisthorchiidaeGenus ClonorchisSpecies 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

3
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.

4
Question!

• Why is Clonorchis sinensis known as the
  Chinese/Oriental liver fluke?
• Because out of the 601 million, 570 million are
  Chinese and Taiwanese. It is found predominantly
  in the regions of the world that raw fish is a
  delicacy.

5
Geographic Distribution

• Japan
• Korea
• China
• Taiwan
• Vietnam

6
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

7
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

8
Life Cycle
9
A Closer Look At the Life Cycle

• Egg of C. sinensis that contains miracidium
  floats in fresh water until it is ingested by a
  snail
• It will then develop into a sporocyst, which
  houses the asexual reproduction of redia
• Redia will themselves asexually reproduce to form
  the cercariae
• Cercariae are the free-swimming form of the
  parasites that enables the second intermediate
  host to be infected

10
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.

11
Life Cycle cont.

• The cercariae will then actively bore themselves
  out of the snail
• It will then seek out a fish, and bore into the
  skin/flesh of its target
• Once inside the second intermediate host, the
  cercariae will become a metacercarial cyst

12
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
  

13
Life Cycle cont.

• Once in the small intestine, the metacercariae
  will excyst
• They will then navigate to the liver
• Once at the liver, the Clonorchis will achieve
  its sexual maturity stage
• The hemaphroditic adults produce eggs every 1 -
  30 seconds

14
Picture of C. sinensis
15
Pictures cont.
16
Sites of Infection

• Infection occurs in the liver
• Bile duct is preferred site
• The parasite feeds on the bile

17
Pathogenesis/Clinical Signs

• Infection is usually asymptomatic however, heavy
  infestation may cause biliary obstruction
• Loss of appetite
• Nausea
• Diarrhea
• The sensation of abdominal pressure or pain
• Rarely, bile duct obstruction may produce
  jaundice followed by cirrhosis
• Enlargement and tenderness of the liver

18
Pathogenesis/Clinical Signs Continued

• Could result in the common bile duct and/or gall
  bladder to explode within the human body
• May cause adenocarninoma of the bile ducts
  (cholangiocarcinoma)
• Loss of fat digestion (severe infestation)

19
Diagnosis

• Fecal smears and examinations
• Duodenal aspirate
• Adult flukes can also be recovered at surgery

20
Treatment

• Drugs
• Praziquantel (most effective)
• Albendazole

21
Control Maneuvers

• Physical inactivation Sensitive to heating at
  56C for 30 minutes for all infectious stages
• Survival outside host Sensitive to freezing
• Susceptible to disinfectants All infective
  stages are susceptible to 1 sodium hypochlorite

22
Other Control Measures?

• What other control measures can be used to curb
  the prevalence of this parasite?
• Sanitation
• Human feces as fertilizer
• Think oral-fecal contamination measures

23
FYI

• BE WARNED!
• Metacercariae can remain viable even after the
  fish has been pickled, salted, dried, or smoked

24
Works Cited

• http//www.phac-aspc.gc.ca/msds-ftss/msds34e.html
• http//animaldiversity.ummz.umich.edu/site/account
  s/information/Clonorchis_sinensis.html
• http//www.k-state.edu/parasitology/625tutorials/C
  lonor02.html
• http//www.k-state.edu/parasitology/625tutorials/T
  rematodes08.html
• http//en.wikipedia.org/wiki/Clonorchis_sinensis
• Text Book