Abstract
Nematodes and cestodes are present in almost all animals and humans. These parasites spread to a considerable degree among animals that are continuously grazing because in the case of nematodes, the eggs or larvae excreted in the feces leas to and immediate subsequent infection when they are ingested orally with food. Infections also occur very simply in the case of tapeworms, even though in most cases intermediate hosts are involved, which are likewise infected by the egg- or larvae-containing piles of feces of infected grazing phase, particularly when the animals stay close together, for example in mass production farms. Infestations with nematodes and cestodes are therefore a major problem threatening the rearing of livestock animals, ruminants in particular, because of the reduction in weight related to the amount of worms. The present chapter gives an overviews on the efficiency of various plant extracts on trematodes, tapeworms and nematodes. In detail it is described, that extracts of onion bulbs and of coconut given at the same time-are able to control infections due to platyhelminths and round worms in animals. These experiments are so convincing that products may become bunched soon onto the agricultural markets.