A review of the use of Duddingtonia flagrans as a biological controller of strongylid nematodes in horses

In horses, the nematodes of the Strongylidae family are the most important due to their prevalence and pathogenicity. Sanitary plans include parasite control based on chemical anthelmintics. Among these, the benzimidazole compounds have been used since the 1960s to control the nematode Strongylus vulgaris. Its inappropriate use resulted in the development of resistance in parasites with a shorter biological cycle, such as the small strongyles. Currently, the genera that make up this group show widespread resistance to all chemical treatments available in veterinary medicine, except for macrocyclic lactones, where less effective action has been detected. The need to find alternative routes for its control is recognized. International organizations and markets are increasingly restrictive in the allowed levels of drugs in products of animal origin, so one of the drawbacks is the permanence of chemical compounds in tissues. Therefore, other tools not chemically based are proposed, such as the biological control of gastrointestinal nematodes. Various research groups around the world have carried out tests on the control capacity of the nematophagous fungus Duddingtonia flagrans against this group of parasites. The objective of this review is to compile the different tests that are available on biological control in this species, in in vivo and in vitro tests, and the possible incorporation of this tool as an alternative method of antiparasitic control in an integrated control scheme of parasites.