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 Morphology Taxonomy 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

MORPHOLOGY

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 1st 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 Eggs passed on through feces Miracidia Sporocysts Eggs ingested by snail Rediae Cercaria Free floating cercariae encyst Metacercaria in skin or flesh of fish Metacercaria ingested by human host Excyst in duodenum & adults in biliary duct

Life Cycle

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 1st intermediate host: snail 2nd 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 Infection due to using metacercaria-contaminated 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 Albendazole 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" (On-line), Animal Diversity Web. Accessed October 07, 2006 at <http://animaldiversity.ummz.umich.edu/site/accounts/information/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 MacMillan 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/chapter21/intro.htm www.dpd.cdc.gov/dpdx/HTML/Frames/A-F/Clonorchiasis www.cdc.gov/nvidod/eid/vol3no3/hotez.htm http://www.biosci.ohio-state.edu/~parasite/digenetic_trematodes.html http://www.dpd.cdc.gov/dpdx/HTML/Clonorchiasis.htm http://clonorchiasis.blogspot.com/ http://tmcr.usuhs.mil/tmcr/chapter21/epidemiology.htm http://www.kstate.edu/parasitology/625tutorials/Trematodes08.html http://www.kstate.edu/parasitology/625tutorials/Clonor01.html