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Clonorchis Sinensis Lida Shaygan
What is Clonorchis Sinensis? • Chronic infection caused by the liver fluke • Parasitic worm 10 -25 mm long • Lives in bile ducts of liver in humans and other mammals • Acquired by eating fresh water fish containing fluke larvae. • One of the most severe food-borne parasitic diseases in China
Taxonomy & Morphology • Hermaphrodite • Digenetic • Unsegmented • Leaf- shaped • Bilaterally symmetrical excretory system • Bear 2 suckers • Ventral • Oral • Oblong shaped • Flat (platyhelminthes) • relatively small 10 -25 mm in length • Taxonomy Kingdom: Animalia Class: Platyhelminthes Order: Trematoda Family: Opisthorchiidae Genus: Clonorchis Species: Sinensis
Egg • oval-shaped, 26 -30 micrometers in length, has a thick yellow-brown shell surrounding it. • Embryonated eggs are discharged in the biliary ducts and in the stool
The Snail 1 st Intermediate Host • Eggs are ingested by a suitable snail intermediate host • there are more than 100 species of snails that can serve as intermediate hosts.
Developmental Stages Each egg releases a miracidia , which goes through several developmental stages:
Metacercariae • After a short period of free-swimming time in water, cercariae come into contact and penetrate the flesh of freshwater fish, where they encyst as metacercariae
Adult Fluke • Metacercariae excyst in the duodenum and ascend the biliary tract • Maturation takes approximately 1 month. • The adult flukes (measuring 10 to 25 mm by 3 to 5 mm) reside in small and medium sized biliary ducts.
Life Cycle 1. Eggs passed on through feces 2. Miracidia 3. Sporocysts 4. Eggs ingested by snail 5. Rediae 6. Cercaria 7. Free floating cercariae encyst 8. Metacercaria in skin or flesh of fish 9. Metacercaria ingested by human host 10. Excyst in duodenum & adults in biliary duct
Reproduction • Reciprocally Inseminating Simultaneous Hermaphrodite • Polyembryonic proliferation of miricidia to metacercaria • The sporocyst and redia stages asexually reproduce. • A juvenile adult reaches the bile ducts within 4 -7 hours after ingestion • It will then be one month before it is mature enough to start producing eggs.
Hosts • 1 st intermediate host: snail • 2 nd intermediate host: numerous freshwater fish • Hosts ingest metacerariae • Humans and animals (dogs, pigs, cats, rats)
Transmission Factors & Modes of Transmission 1. Eating raw fish or “porridge with raw fish” 2. Eating under-cooked small fish and shrimps 3. Infection due to using metacercariacontaminated utensils or hands
Symptoms • Asymptomatic • Nonspecific symptoms • Acute phases: abdominal pain, nausea, diarrhea, and eosinophilia
Pathogenic Effects • Inflammation & intermittent obstruction of biliary ducts • Dwelling in bile ducts induces • Inflammatory reaction • Hyperplasia • Cholangiocarcinoma (glandular cancer of bile ducts) • Possibility of adult metacercaria to consume all of bile duct in liver • Inhibits host from digesting food • Overcrowding of common bile duct • Risk of bile duct and gallbladder exploding within human body
Detrimental Effects • Eggs and worms that somehow migrate out of the biliary system may become nuclei of eventual gallstones. • Metacercariae travelling through the body can cause high fevers in the host. • May lead to possible disturbance of normal hepatic functions • Clonorchis Sinensis in rabbits leads to higher levels of potassium and cholesterol, lower calcium levels, lipid metabolism and glycogen synthesis are impaired.
Where is it found? • Endemic areas are Asia including Korea, China, Taiwan, and Vietnam. • Occasionally reported in non-endemic areas (including the United States).
Epidemiology • 19 million are infected in heavily populated regions of China • Southern provinces, Taiwan, Hong Kong, Red River, Korea, Japan • Cases also reported in Europe, United States, Middle East, China, Japan, and Africa. • Usually caused by immigrants from regions in China • Acquired by Hawaiians by eating raw, frozen, or salted fish shipped from China or Japan.
New Epidemiological Characteristics • change in diet from mainly grain and vegetable to fish and meats in China • The difference of infection rate between urban and rural areas is reducing. • Endemic area tends to expand gradually.
What Can be Done? • • • Health education Environmental modification Reform of traditional farming and fishing techniques Mass screening and chemotherapy Management of domestic animals are needed in developing control strategies to decrease spreading • Controlling the use of "night soil" (fertilizer contaminated with human feces), used to fertilize fish ponds • Avoid eating raw fish and using contaminated water for consumption.
Diagnosis • Depends on recovering and identifying the parasite’s eggs in stool sample. • Diagnostic Tests: medical history, physical assessment (palpation of the liver), ELISA blood test • Medical Tests: endoscopy and examination of stool sample, radiological and sonographic assessments, surgery
Medications • Praziquantel • Drug of choice for treatment • Increases cell membrane permeability in worms, resulting in paralysis of worm’s musculature • Attachment of phagocytes and death • Cons: bitter taste may cause nausea • Albendazole • Inhibits metabolism in worm’s cells • Immobilization & death of worm follow
Bibliography • Eckroad, E. and H. Lee. 2001. "Clonorchis sinensis" (Online), Animal Diversity Web. Accessed October 07, 2006 at <http: //animaldiversity. ummz. umich. edu/site/accounts/infor mation/Clonorchis_sinensis. html> • Brusca, R. , G. Brusca. 1990. Invertebrates. Sunderland, Massachusetts: Sunauer Associates, Inc. . • Buchsbaum, M. , R. Buchsbaum, V. Pearse, J. Pearse. 1987. Living Invertebrates. Boston, Massachusetts: Blackwell Scientific Publications. • Chappell, L. 1979. Physiology of Parasites. New York: John Wiley and Sons.
Bibliography • Clay, T. , M. Rothschild. 1952. Fleas, Flukes and Cuckoos. New York: The Mac. Millan Company. • Swellengrebel, N. , M. Sterman. 1961. Animal Parasites in Man. Princeton: D. Van Nostrand Company, Inc. . • von Brand, T. 1952. Endoparasitic Animals. New York: Academic Press Inc. , Publishers. • http: //tmcr. usuhs. mil/tmcr/chapter 21/intro. htm • www. dpd. cdc. gov/dpdx/HTML/Frames/A-F/Clonorchiasis • www. cdc. gov/nvidod/eid/vol 3 no 3/hotez. htm • http: //www. biosci. ohiostate. edu/~parasite/digenetic_trematodes. html • http: //www. dpd. cdc. gov/dpdx/HTML/Clonorchiasis. htm • http: //clonorchiasis. blogspot. com/ • http: //tmcr. usuhs. mil/tmcr/chapter 21/epidemiology. htm • http: //www. kstate. edu/parasitology/625 tutorials/Trematodes 08. html • http: //www. kstate. edu/parasitology/625 tutorials/Clonor 01. ht ml