Immunocompetence against gastrointestinal nematodes and its genetic improvement in sheep-1. Infection, immunological response and immunity

On pasture, sheep are exposed to infections with gastrointestinal nematodes. Infections with gastrointestinal nematodes cause damage to the animal and also have economic relevance. In order to avoid an excessive parasite load in the animal and to treat parasitosis, anthelmintics are used for deworming. However, gastrointestinal nematodes are becoming increasingly resistant to anthelmintics, making treatment less and less effective. Accordingly, alternative strategies are required to combat gastrointestinal nematodes. Breeding sheep with increased immunocompetence against gastrointestinal nematodes is a sustainable and long-term strategy. In order to proceed responsibly and effectively, the complexity of infections with gastrointestinal nematodes must be considered in more detail. This review article therefore deals with the infection, the effects of the infection on the animal, the immunological response shown by the animal, the acquired immunity to gastrointestinal nematodes as well as with parasite-host interactions. The article refers to the situation in Germany and concludes with a summary of the need for national action.