Fascioliasis: A Foodborne Disease of Veterinary and Zoonotic Importance

Fascioliasis is a food-borne neglected disease caused by digenetic trematodes in the genus Fasciola. There is a significant increase in the global prevalence of human fascioliasis with a strong correlation with a high infection rate among ruminant definitive hosts. Fasciola is a liver fluke with complex life cycle. Fascioliasis is endemic in every continent of the world with the exception of Antarctica. Discharge of the metabolites of liver flukes into the circulatory system of hosts has pathological consequences. Fascioliasis has been diagnosed by parasitological, immunological, and molecular means, and it is being reliably treated chemotherapeutically. The emerging drug-resistant strains of liver flukes have led to the need for vaccine development. Most vaccine candidates were first isolated as native proteins from adult worms. Several of the early antigens, including cathepsin L proteases, Glutathione S-transferase (GST), and fatty acid binding protein (FABP), significantly reduced worm burden, egg output, and liver pathology in cattle and sheep. Climate change, emerging drug resistance, and the development of new parasite strains through hybridization are the current challenges that could potentially alter the epidemiology of fascioliasis soon. Therefore, researchers need to produce promising vaccines that offer maximum protection to farm animals and humans.