A worm-eating fungus brings new hope in the fight against parasitic gastro-intestinal worms.
Anthelmintic resistance is now a widespread and growing problem. It is becoming increasingly clear that we cannot rely on chemicals alone to control gastro-intestinal parasites.
Consequently, alternative worm control strategies are being investigated. One method showing promise is the use of a fungus that attacks the free-living larval stages of parasitic worms and so reduces the number of infective larvae on the pasture.
Duddingtonia flagrans is a nematophagous fungus (from the Greek for “worm eating”). The fungus grows rapidly in fresh faeces and its chlamydospores (resistant spores) can survive the passage through the gastro-intestinal tract of the horse. These fungal spores have no effect on the animal and only germinate once passed in the faeces where they develop into nematode-trapping fungal nets.
Recent work in Australia showed that feeding BioWorma®, a supplement containing the Duddingtonia spores, produced substantial reductions in infective larvae on pasture surrounding faeces of treated horses, cattle and goats.
The placebo-controlled trials were conducted in different seasons and bioclimatic regions of Australia (New South Wales, Queensland).
Faeces were collected from worm-infected animals after they had been treated with either the D flagrans supplement or a placebo. The manure was placed on pasture plots and the researchers monitored the numbers of parasitic larvae on the pasture around the faecal pats over an eight-week period.
They report that a minimum daily dose of 3 × 104 D flagrans spores/kg bodyweight reduced parasite larvae in the pasture surrounding the faeces by 53–99 % over the eight-week period after treatment in horses, cattle and goats.
Other work has shown that, unlike some chemical wormers, the fungus does not harm dung beetles or other organisms found in the faeces.
BioWorma® is about to be approved for sale in Australia and New Zealand. It should be available in the United States shortly and in Europe within the next year or two.
For more details, see the following open access article:
Field evaluation of Duddingtonia flagrans IAH 1297 for the reduction of worm burden in grazing animals: Pasture larval studies in horses, cattle and goats
Kevin Healey, Chris Lawlor, Malcolm R.Knox, Michael Chambers, Jane Lamb, Peter Groves
Veterinary Parasitology. Vol 258, pp 124-132