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Microscopic fungi are the latest weapon in the war against worm parasites.
These worm-devouring fungi are being used by CSIRO to ambush and destroy worms before they can infect animals such as sheep and cattle.
Research by CSIRO Division of Animal Production scientists Dr Peter Waller and Ms Margaret Faedo has found that these special naturally occurring fungi will live in animal dung along with worm parasites.
Normally sheep are infected by eating grasses containing these tiny worm parasites and this can cause animal production losses through poor health, parasitic diseases and even death.
"Australian sheep producers are losing about $340 million each year due to losses in animal production caused by worms," said Dr Peter Waller of the Division of Animal Production.
"We have now isolated Australian worm-devouring fungi that can be fed to sheep. The fungi pass through the sheep and are finally excreted together with worm eggs in the sheep's dung."
"The fungi form amazing threadlike networks in the dung and send out lassoes that trap the worms when they hatch. Once trapped, the fungi penetrate and devour the worms."
"It is extremely unlikely that the worms will find a way to fight back" Dr Waller said. "It is a form of biological control that looks most promising."
"The fungi are remarkably effective because they can attack all important nematode worm parasites. This form of control is not restricted to one worm species, which is a limitation to approaches that rely on vaccines."
"This technology is equally applicable to control worm parasites in all livestock - cattle, sheep, pigs, horses and other animal production systems."
"In rural Australia, farmers traditionally use chemical drugs (drenches) to kill worms. However, the worms are now becoming increasingly resistant to these treatments."
"Farmers are becoming desperate in their battle to control worms. More than 80% of sheep farms in high rainfall regions (with more than 500 mm of rain per year) have a problem with worm resistance to two of the three available classes of drugs."
"Reports of increasing resistance to the remaining drug treatment are becoming more frequent. It is highly unlikely that any new types of drugs will be available this century due to the very high costs and risks associated with developing new products."
"It is vital that we develop alternative non-chemical solutions to control worm infections."
"Although the existence of worm-destroying fungi has been known for many years, very little work has been done in Australia until recently. In our search for the ideal naturally occurring fungi, we screened over 2000 fresh dung samples obtained from grazing animals in various regions throughout Australia."
"We have now found the best fungi to use to control the worm parasite problem. For fungi to be a practical proposition, they must survive passage through the gut of an animal and be able to colonise and thrive in fresh dung."
"Rather than treating the worm parasites in the animal, as is the case with drenches, this form of biological control attacks the free living parasite in the field and breaks its life cycle," explained Dr Waller. "Biological control will not remove the worms completely from pastures but is expected to eliminate the rise in worm numbers which leads to production losses and parasitic diseases in animals."
"We have been looking at various ways of administering fungi to sheep, and our research has shown that feed blocks containing fungi show great promise in pen trials, and these are currently being tested in the field. Dosing the sheep with capsules containing the fungi is an alternative approach which we are also investigating."
"We are now at the stage where we need to undertake more extensive field testing to determine the form of dosing best suited for Australian conditions."
"The use of fungi has great potential, and we anticipate that it could be readily scaled up for commercial use for farmers to use as a suitable worm control strategy in the not too distant future."
For further information please contact:
Peter Waller at CSIRO Division of Animal Production, Armidale
Video footage of fungi devouring worms is available, as well as cartoons.
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