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Synonyms of Fascioliasis

  • Fasciolosis
  • Liver fluke disease

Disorder Subdivisions

  • Halzoun Syndrome

General Discussion

Fascioliasis is a rare infectious disorder caused by parasites. These parasites are liver flukes that live in plant-eating animals. Liver flukes can be found on water plants in certain parts of the world. When the parasite invades the liver, bile passages may be blocked. A subdivision of Fascioliasis called Halzoun Syndrome affects the throat (pharynx). This infection can usually be controlled and/or cured with timely treatment.


The disease has three phases: acute, latent, and chronic. The acute phase begins approximately four days after infection and can last for two to four months. Symptoms during this phase include fever, abdominal pain with tender liver, gastrointestinal disturbances, and hives (urticaria) accompanied by bouts of bronchial asthma. The latent phase begins when mature flukes reach the bile duct and can last for several months. Individuals in this phase are asymptomatic. The chronic phase can persist for several years. Symptoms include gastrointestinal pain, fatty food intolerance, nausea, jaundice, itching, and abdominal tenderness.


Fascioliasis is caused by infection with the parasitic worms of the genus Fasciola, of which "Fasciola hepatica", found in temperate climates, and "Fasciola gigantica", found in tropical climates, are the most common. Encysted parasitic larvae of these parasites live on water plants, such as watercress, that may be eaten by man or eaten by animals that subsequently are eaten by man. Once ingested, the larvae escape from the cysts in the small intestine and migrate across the intestinal wall into the abdominal cavity. They transform into immature worms and, once they reach the liver, move around for up to six weeks, feeding on liver tissue. Eventually, they take up residence in the bile ducts, where they cause lesions and chronic liver disease. Generally, the parasite can be killed by adequate cooking of foods before they are eaten.

Affected Populations

Fascioliasis is rare in the United States, but sometimes occurs in southern and western areas of the nation where goats and sheep are raised. The parasites can be passed to man through goat or sheep meat that is inadequately cooked. This disorder tends to be more prevalent in the Orient and the tropics. An estimated that 2.4 million people are infected worldwide. An outbreak in northern Iran in 1989 and 1991 affected more than 10,000 people. Other outbreaks have occurred in Algeria, Cuba, and France. According to the World Health Organization, the infection is present in domestic animals in almost all countries where cattle and sheet are reared.

The disease affects both sexes and all ages. It is highly prevalent in Ecuador, Peru, Bolivia, Chile, Iran, and Egypt. Sporadic outbreaks occur in countries such as Portugal, France, and Spain.

Related Disorders

Other infectious disorders caused by parasites may be due to round worms, tape worms, protozoan organisms, flukes and other bacteria.

Halzoun Syndrome is a variant of Fascioliasis. This disorder affects the throat. It is caused by eating "Fasciola Hepatica", "Fasciola Gigantica" or other parasites known as "Linguatulid" larvae.

Standard Therapies

Liver fluke disease should be suspected if the patient recently spent time in a region where infection is prevalent in animals and/or humans. Patients usually report eating wild watercress, algae, or other aquatic plants. Acute and chronic infection can be confirmed by testing that detects liver fluke-specific antibodies in body fluids. Also, parasite eggs may be detected in the stool at the chronic stage of infection.

Prompt treatment of Fascioliasis is necessary to prevent liver complications caused by this disorder. Liver fluke disease can be successfully treated using the drug, Triclabendazole. This drug is administered after consumption of food and usually in a single dose. In severe cases, two doses may be administered, 12 hours apart. It is effective against both adult and immature worms.

The drug previously used, bithionol, had to be administered orally over five days, and another drug, praziquantel, which is effective against some similar parasitic organisms, is not effective against the Fasciola species.

Inspection programs of animals in high risk areas can do much to control the spread of this infection. Most importantly, all meats should be well cooked before they are eaten by man.

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010

For information about clinical trials sponsored by private sources, contact:

Fascioliasis Resources



O'Neill SM, Dalton JP. Fascioliasis (Liver Fluke Disease). NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:286.

Dalton JP. Fasciolosis. CABI Publishers. Wallingford, UK. 1999.

LaPook jd, Magun AM, Nickerson KG, et al. Sheep, watercress, and the internet. Lancet. 2000;345:462.

el-Karaksy H, et al., Human fascioliasis in Egyptian children: successful treatment with triclabendazole. J Trop Pediatr. 1999;45:135-138.

O'Neill SM, Parkinson M, Strauss W, et al. Immunodiagnosis of Fasciola hepatica infection (fasciolosis) in a human population in the Bolivian Altiplano using purified cathepsin LI cysteine proteinase. Am J Trop Med Hyg. 1998;58:417-23.

Dias LM, et al., Biliary fascioliasis: diagnosis, treatment and follow-up by ERCP. Gastrointest Endosc. 1996;43:616-620.

Bhargava DK, Endoscopy and biliary parasites. Gastrointest Endosc Clin N Am. 1996;6:139-152.

el-Newihi HM, et al., Biliary complications of Fasciola hepatica: the role of ectoscopic retrograde cholangiography in management. J Clin Gastroenterol. 1995;21:309-311.

Tendler M, Vaccination against schistosomiasis and fascioliasis with the new recombinant antigen Sm 14: potential basis for a multi-valent anti-helminth vaccine? Mem Inst Oswaldo Cruz.

Loutan L, Bouvier M, Rojanawisut B, et al. Single treatment of invasive fascioliasis with triclabendazole. Lancet. 1989;2:383.

The information in NORD’s Rare Disease Database is for educational purposes only. It should never be used for diagnostic or treatment purposes. If you have questions regarding a medical condition, always seek the advice of your physician or other qualified health professional. NORD’s reports provide a brief overview of rare diseases. For more specific information, we encourage you to contact your personal physician or the agencies listed as “Resources” on this report.

Report last updated: 2009/05/12 00:00:00 GMT+0

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