Clonorchiasis

Clonorchiasis

Clonorchiasis is an infection endemic in certain parts of the world particularly in the Far East. The causative organism is called Clonorchis sinensis. The disease is typically acquired by eating undercooked or pickled freshwater fish. ^{[1] [2]}

Epidemiology

Some countries where the infection is common include Korea, China, Vietnam and Taiwan.

Causes

Clonorchiasis undergoes a cycle. Clonorchis sinensis is a parasitic worm that resides in the bile duct of an infected person. The eggs are released in the stool and ingested by snails. Eventually, larvae from these eggs infect freshwater fish. Humans get the disease when they consume these infected fishes. Frequently, infection occurs after eating undercooked, salted, pickled, or smoked freshwater fish. ^[1]

Signs and Symptoms

People who get light infections do not experience symptoms usually. Those who are infected heavier may experience fever, chills, abdominal pain and jaundice or yellowing of the skin and the white portion of the eyes. The liver may enlarge and diarrhea may occur. Blood test may show elevated levels of eosinophil. ^[1]

Chronic clonorchiasis is a severe form resulting from repeated infections. The worms that inhabit the bile duct causes inflammation of these parts which in due course leads to fibrosis. In some cases, cholangiohepatitis, or recurrent pyogenic cholangitis may also be the upshots. Certain people also may develop complications like chronic pancreatitis. Chronic clonorchiasis is also linked to a type of cancer called cholangiocarcinoma. ^[3]

Diagnosis

Medical history is important to make a physician suspect clonorchiasis. After a physical examination, the patient often undergoes complete blood count. Eosinophil is often increased. Diagnosis of clonorchiasis is usually made after microscopic examination of the patient’s stool. Immunological and molecular techniques are also available as diagnostic tools. ^{[1] [3]}

Treatment

Praziquantel is the drug of choice. It is usually prescribed at 25 mg/kg thrice daily for 2–3 consecutive days or single dose of 40 mg/kg. ^[3] When there is obstruction, surgery may be necessary. Prevention among endemic areas is highly promoted. Freshwater fishes should be cooked thoroughly. To be safer, people are advised not to consume raw, pickled, or wine-soaked freshwater fishes. ^[1]

References:

1.      http://www.merckmanuals.com/professional/infectious_diseases/trematodes_flukes/clonorchiasis.html

2.      http://www.dpd.cdc.gov/dpdx/HTML/Clonorchiasis.htm

3.      http://www.who.int/foodborne_trematode_infections/clonorchiasis/en/

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