Fascioliasis is a helminthiasis, from the group of trematodoses, a disease of many species of mammals caused by the trematode Fasciola hepatica (Fasciola vulgaris). The causative agent is F. hepatica, a large trematode leaf-shaped, flat. The parasite is 20–30 mm long and 5–12 mm wide.
Fasciola parasitizes in the adult state in the bile ducts of the liver, sometimes in the gall bladder, in the early stages in the liver tissue in nutria, rabbits, many wild and domestic mammals, and in humans.
Sources and routes of infection
Fascioli develops with the participation of intermediate hosts – freshwater mollusks, which are most often found in moist, especially water-flooded areas. Adult parasites lay eggs in the liver of sick animals, which enter the intestines with bile, from where they enter the external environment with feces. Under favorable conditions, larvae (miracidia) develop from eggs in 10-12 days. In the external environment, eggs are very stable. With sufficient humidity, they retain the ability to develop throughout the year. Miracidia are actively introduced into the body of the intermediate host. In the liver, they turn into tailed larvae that leave the mollusk and swim freely in the water. The fasciol development cycle in the intermediate host lasts about three months, depending on temperature conditions. In water, cercariae become coated and turn into adolescari. They float freely in water bodies, sink to the bottom or attach to aquatic plants. Most animals become infected in the pasture.
Fascioliasis is acute or chronic. In the acute form of fascioliasis, animals lose their appetite, lethargic, lie for a long time, lose weight quickly, the fur becomes disheveled. Progressive weakness is noted. The incisors lose their orange-yellow color and acquire a gray-yellow or even grayish-white color. There is pain in the liver. In individual animals, body temperature rises to 39-40 degrees Celsius. Sometimes before death there are nervous excitement and cramps. Nutria die due to exhaustion, or from purulent inflammation of the bile ducts. Toxins released by parasites poison the body. There are changes in the morphological and chemical composition of the blood. Cattle reduces milk yield. Small cattle (goats, sheep) die with intense invasion.
In the acute form of fascioliasis – a triple dose of per os bithionol in a dose of 0.2 g / kg of animal weight with a one-day interval between doses. In case of chronic fascioliasis and for prophylaxis, albendatim-100 is used once in a dose of 0.2 g / kg of nutria mass, 22% tymbndazole is granulated at 0.045 g / kg. Treatment measures play a secondary role compared to preventive measures, since the disease is often detected after the slaughter of animals. In order to avoid infection, it is not necessary to give nutrias food from moist meadows and pastures that are unsuccessful due to the disease. You can’t water animals with water from open, stagnant water bodies (swampy lakes, ponds, etc.) and feed them grass from areas inhabited by mollusks – intermediate hosts of parasites.