Explain the meaning and relationship of the terms “intermediate host” and “final host”. Using the example of a bovine tapeworm, describe how the host change of the parasite occurs.
The hepatic fluke is hermaphrodite. It forms eggs, which enter the intestines of the host, and from there are excreted. Eggs develop only in water. Here, a free-swimming larva with cilia emerges from the egg, which penetrates into the body of an intermediate host – a small pond snail. There, the larva grows and multiplies, forming a new generation of larvae. They leave the body of the pond snail into the water and settle in the reservoir. The larvae then attach to the leaves of aquatic plants, become covered with membranes and turn into cysts. When drinking water and eating grass, livestock becomes infected with hepatic fluke cysts. In the intestine, cysts burst. Young flukes emerge from them and enter the liver.
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