Fascioliasis is a liver fluke disease in the sheep and cattle areas of the world. Most cases in the USA are imported. In this trematode infection of bile ducts, humans are infected by eating plants, such as watercress, to which metacercariae have attached.
CASES/YEAR
50 (US); 17,000,000 (Global)
OTHER NAMES
Fasciola hepatica; Fasciola gigantica; Liver fluke (Fascioliasis);
INCUBATION
Acute symptoms may occur 4-7 days after exposure; Chronic symptoms may begin months to years after exposure; [CCDM] Eggs detectable in stool about 1-2 months after first symptoms; [PPID, p. 3459]
INITIAL SYMPTOMS
Abdominal pain, fever, eosinophilia, weight loss, and urticaria; [Guerrant]
PRECAUTIONS
"Infection is not transmitted directly from person to person." [CCDM, p. 208]
COMMENTS
EPIDEMIOLOGY:
In this trematode infection of bile ducts, humans are infected by eating plants, such as watercress, to which metacercariae have attached. Sheep and cattle are the natural hosts for F. hepatica. Metacercariae in drinking water may transmit infection. [CCDM, p. 207-8] F. hepatica is more widely distributed affecting over 2 million people in Bolivia, Peru, Iran, Egypt, Portugal, and France. Goats, camels, llamas, deer, pigs, horses, rabbits, and other wild animals also serve as reservoirs. [Guerrant, p. 859] Most cases in the USA are imported. [PPID, p. 3459] Transmission after eating raw liver containing immature flukes has been reported. [Harrison ID, p. 1151]
FINDINGS:
The hepatic or invasive stage lasts for several months. Symptoms during this stage include eosinophilia, abdominal pain, intermittent fever, weight loss, and urticaria. The liver may be enlarged and tender. CT scan or liver biopsy may reveal the hepatic microabscesses. The flukes rarely migrate to other organs and may cause cutaneous larva migrans. The chronic biliary stage begins when the flukes migrate to the biliary ducts to mature. The symptoms from the first stage abate, and the patient may become asymptomatic, but some patients develop recurrent biliary colic and some have episodes of ascending cholangitis with fever, jaundice, and abdominal pain. Another complication is stones in the gallbladder or common bile duct. Marked eosinophilia is present early. Eosinophilia may or may not be present during chronic infection. Cutaneous larva migrans has been reported with migrating erythematous nodules. CT scans may reveal migrating hypo-dense lesions in the liver. [Guerrant, p. 858-61] Patients develop the first symptoms about 6-12 weeks after ingestion. In addition to eosinophilia, fever, urticaria, and hepatomegaly, about 10% of patients have cough and chest pain, sometime associated with pleural effusion. Lesions may be detected in the liver, lung, brain, and GU tract. The acute symptoms last up to 4 months. Chronic fascioliasis is subclinical except for episodes of bile duct obstruction or occasionally ascending cholangitis. [PPID, p. 3459] Serologic tests may be useful during the acute phase since egg production does not start until 3-4 months after exposure. [CDC Travel, p. 210] Acute fascioliasis resembles acute cholecystitis. Eosinophilia occurs in about 50% of chronic patients. Alkaline phosphatase is commonly elevated and reflects biliary obstruction. [Cecil, p. 2126]
DIAGNOSTIC
Chronic infection: identification of eggs in stool; eggs or adults in surgical specimens; Acute infection: clinical dx & ELISA Ag detection; [Guerrant, p. 861] Serology (suggest disease when +); Eggs in stool or bile aspirated from duodenum; [CCDM]
SCOPE
Sheep and cattle areas of the world; Sporadic cases in the USA; Hyperendemic in Andean highlands of Bolivia and Peru; Outbreaks have occurred in other countries; [CCDM]
SIGNS & SYMPTOMS
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>arthralgia
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>fever
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G abdominal pain
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G diarrhea
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G hepatomegaly
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G jaundice
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G liver function test, abnormal
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G nausea, vomiting
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H anemia
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H eosinophilia
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H lymphadenopathy
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R chest pain
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R cough
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R dyspnea
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S skin or subcutaneous nodule
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S urticaria
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S skin lesion, linear or serpiginous
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X cystic or cavitary lesions
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X pleural effusions
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*brain abscess or lesion
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*meningitis
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*pancreatitis
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*weight loss
SOURCE
Animal Tissue, Eating Contaminated Food, Eating Contaminated or Infected Meat, Eating Contaminated Produce, Waterborne (Ingesting, Inhaling, or Swimming)
RESERVOIR
Cattle, Goats and Sheep, Deer, Elk and Antelope, Horses, Rabbits, Swine, Human, Wild Animals
RISK FACTORS
- Ingest infectious agents in food/water
- Travel to endemic area
TREATMENT
Triclabendazole is the drug of choice. [CCDM]
REFERENCES FOR CASES/YEAR
1. (US) A small number of cases, mostly imported, have been reported in the US; [PPID, p. 3459] Guesstimate: 50 cases/year;
2. (Global) 56 million suffered and 7000 died from foodborne trematodiases in 2005; [Fact sheets from WHO] Worldwide prevalence of 17 million cases; [Harrison ID, p. 1151]