Fasciolosis – Transmission, Symptoms, Complications and Treatment
is a parasitic infection which essentially affect the bile ducts of the liver and the gallbladder. It is caused by two helminths which are identified as trematodes (parasitic flatworms referred to as flukes). The first one is Fasciola Hepatica (F. Hepatica), common liver fluke and the second one is Fasciola Gigantica (F. Gigantica). The adult worm F. Hepatica could be around 2 to 3 centimeters in length and gets lodged in the bile ducts or the gall bladder.
Earlier the disease would be mostly limited to animals. But now the World Health Organisation (WHO) has recognized it as an emerging human disease. It is a serious public health issue today. It is estimated that around 2.4 million people are infected with the said parasite and another 180 million are in the susceptible category. Fasciola Hepatica is the variety that is commonly found in Europe, North and South America. Many areas of Africa and Asia have the prevalence of both the varieties.
How is Fasciolosis transmitted?
The life cycle of the said parasite can give a clear picture of how the disease is transmitted.
- The host could be a human or an animal which releases immature eggs in the stool. Snail is an intermediate carrier of these eggs.
- In the snail the eggs mature into cerceriae ( larva of the parasite) and are released in the water. These larva encyst on the aquatic vegetation and other surfaces.
- Consumption of such aquatic vegetation especially water cress allows the larva to enter the digestive tract of the host.
- After consumption, the larve lodges itself on the duodenum and eventually bores through the intestinal wall to reach the biliary ducts of the liver where it grows into an adult worm.
- The worm is also transmitted on human consumption of raw or undercooked liver of infected animals.
What are the symptoms of the infection caused by the Fasciola parasite?
The incubation phase (the period between the ingestion of the larva and its migration to the bile ducts ) could be without any symptoms.
The invasive or the acute phase (when the fluke is lodged on to the bile ducts) essentially involve general symptoms of toxicity and infection. It is often indicative of permanent damage to the tissue of the bile ducts and the liver. The significant symptoms of this phase are as follows:
- Gastrointestinal abnormalities like nausea, bloating, flatulence, diarrhea, loss of appetite etc.
- Allergic reactions on the skin like Urticaria. It involves the emergence of red itchy welts on the skin with predefined edges.
- Moderate to severe abdominal pain.
- Abnormal enlargement of the liver and spleen as in Hepatomegaly or Splenomegaly respectively.
- Anaemia or a drop in the haemoglobin count in blood.
- Jaundice or yellowing of skin caused by the abnormal build up of excess bilirubin in the body.
- Ascites or the retention of fluid in the peritoneal cavity of the abdomen (the cavity in between the membranous covering of the intestinal wall and that of the abdominal organs).
The disease involves a serious infection of the bile ducts whereby the adult flukes in it causes hyperplasia or an abnormal proliferation of cells in the region causing undesirable inflammation and enlargement. The resulting cholangitis (inflammation of bile ducts) and cholecystitis (inflammation of pancreas) may cause an obstruction in the bile ducts inhibiting the flow of the bile. This condition causes permanent damage to the bile ducts of the liver and gall bladder and in rare circumstances has led to cholangicarcinoma ( cancer of the bile ducts).
Treatment of Fasciolosis
- It is mostly managed with anti helminthic drugs like Triclabendazole or Bithionol, Praziquantel, Nitazoxanide etc.
- Surgical intervention may be needed when the adult worm in the bile duct causes biliary obstruction.
- A protein rich diet along with sufficient rest is needed to make a full recovery.
- Irons and vitamin supplements are usually prescribed.
- Lastly, a preventive measure which involves thoroughly washing aquatic plants and cooking them before consumption is definitely recommended.