A review on fascioliasis in Egypt

Fascioliasis, caused by Fasciola species, is a disease of herbivorous animals. It has a worldwide distribution in a large variety of grass-grazing animals as sheep, goats, cattle, buffaloes, horses and rabbits. In Egypt, donkeys and camels as well, are hosts for F. gigantica. Fascioliasis may occasionally affect man. Human infection causes serious hepatic pathological sequences that add to the already known threats to the liver of the Egyptian population. Two clinical stages are recognized in human fascioliasis. An acute stage coincides with the larval migration and worm maturation in the hepatic tissue, and a chronic stage coincides with the persistence of Fasciola worms in the bile ducts. Human infection with fascioliasis was very sporadic until the last three decades where clinical cases and outbreaks were reported. The estimated the number of people currently having fascioliasis to be 360,000 in Bolivia, 20,000 in Ecuador, 830,000 in Egypt, 10,000 in Islamic Republic of Iran, 742,000 in Peru, and 37,000 in Yemen. The total estimated number of people infected is 2.4 million in 61 countries and that the number at risk is more than 180 million throughout the world. Human fascioliasis has to be differentially diagnosed from some diseases as acute hepatitis, infection with other liver flukes as schistosomiasis, visceral toxocariasis, biliary tract diseases and hepatic amoebiasis. The parasitological diagnosis is based on identification of eggs in stool, duodenal contents or bile, also by the recovery of adult worm during surgical exploration, after treatment or at autopsy. However, the eggs may be present in very small number at irregular intervals, hence difficult to be found. Besides, the eggs may be transiently present in stool after ingestion of raw or undercooked liver from infected animals. The direct methods of diagnosing the egg are usually unsatisfactory. The symptoms may be present for several weeks before eggs are recovered in stool. Thus, the serologic tests are the alternative method of confirming early and extrabiliary human fascioliasis. However, cross-reactions with other helminthic antigen may confuse the interpretation of the results.