Clonorchiasis is limited to China (except NW), Japan (rarely), Taiwan, Korea, Vietnam, and probable Laos and Cambodia. Complications of chronic infection include obstructive jaundice, cholangitis, pancreatitis, cirrhosis, and cholangiocarcinoma. The source of infection is eating undercooked fish.
CASES/YEAR
0 (US); 15,000,000 (Global)
OTHER NAMES
Chinese or oriental liver fluke disease; Liver flukes (Clonorchiasis)
INCUBATION
Flukes reach maturity about one month after ingestion of encysted larvae; [CCDM]
INITIAL SYMPTOMS
Often asymptomatic; Symptoms of heavy infections include loss of appetite, diarrhea, and abdominal pressure; [CCDM, p. 358].
PRECAUTIONS
"Infected individuals may pass viable eggs for as long as 30 years; infection is not directly transmitted from person to person." [CCDM, p. 359]
COMMENTS
Snails are the first and fish the second intermediate hosts for these trematode infections. Humans become infected after eating undercooked, salted, pickled, or smoked freshwater fish. Flukes mature and lay eggs in the biliary ducts. Patients with acute infections are usually asymptomatic. Some patients have an acute illness with fever, fatigue, abdominal pain, eosinophilia, and hepatomegaly. Patients with chronic infections may have hepatomegaly and malnutrition. Marked eosinophilia is present early and may or may not be present during chronic infection. Complications of chronic infection include obstructive jaundice, cholangitis, pancreatitis, cirrhosis, and cholangiocarcinoma. Reservoirs include humans, cats, dogs, swine, and rats. [Guerrant, p. 943, 854-8; CCDM, p. 358-60; http://www.dpd.cdc.gov/dpdx/] Jaundice does not occur during acute infection. When jaundice is present, cholangiocarcinoma should be suspected. [Cecil, p. 2126] Patients with chronic disease may have episodes of cholangitis with bacterial sepsis. [PPID, p. 3459]
DIAGNOSTIC
Microscope: eggs in stool or duodenal aspirate; Ultrasound, MRI, or CT: cystic changes in the liver; Acute infection: Hx of ingestion of raw freshwater fish, then several wks later upper GI pain, eosinophilia, LFTs & eggs in stool; [Guerrant]
SCOPE
C. sinensis in China except NW; Japan (rarely), Taiwan, Korea, Vietnam, and probably Laos and Cambodia; [CCDM]
SIGNS & SYMPTOMS
-
>fatigue, weakness
-
>fever
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G abdominal pain
-
G diarrhea
-
G hepatomegaly
-
G jaundice
-
G liver function test, abnormal
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G nausea, vomiting
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H eosinophilia
-
H leukocytosis
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S urticaria
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*cancer
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*cirrhosis
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*hepatitis
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*pancreatitis
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*sepsis
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*weight loss
SOURCE
Animal Tissue, Eating Contaminated Food, Eating Infected or Toxin-Containing Fish
RESERVOIR
Cats, Dogs, Fish and Shellfish, Rodents, Swine, Human
RISK FACTORS
- Eat undercooked meat or fish
- Travel to endemic area
TREATMENT
Praziquantel is the drug of choice. [CCDM]
REFERENCES FOR CASES/YEAR
1.
2. (Global) 56 million suffered and 7000 died from foodborne trematodiases in 2005; [Fact sheets from WHO] About 15 million infected with C. sinensis; [CCDM, p. 359]