VetScan 2009 Vol 4 No 1 Article 31

Biological control of animal parasites could become a strong arm for Integrated Parasite Control in the very near future. Though various nematode-destroying fungi received attention, predominantly on academic interest, from the 18th Century in Scandinavian countries, work on their application to control animal parasites gathered momentum from 1990's. The philosophy behind biological control is to utilise one or more of the natural enemies of the nematodes, making it possible to reduce the infection on pasture to a level where grazing animals can avoid both clinical and subclinical effects of the parasitic nematodes. The important requirement is the presence of the fungi in the faecal pats where the development of the pre-parasitic larvae takes place. Therefore, to be effective, the fungi should pass through the gastrointestinal tract of the host without loss of viability. The fungi, Duddingtonia flagrans and Verticillium chlamydosporium, which can be isolated from organic environment of India produces thick walled chlamydospores, the stage responsible for their survival during passage through the gut of ruminants following oral administration. The results had indicated survival of the fungus during gastrointestinal transit in grazing animals and successful reduction of numbers of parasitic nematode larvae on pasture. The dose of fungal spores to be given to an animal and the time of administration for effective parasite control has been standardised. The fungus behaves in density dependent manner and appears to be environment-friendly. The challenge lies ahead in its field application.