Novel approaches to control of parasites—a workshop.

With the advent of helminth parasite populations that have developed resistance to anthelmintics over the last decade or so, especially in small ruminants, sustainable productivity has been threatened. This workshop on novel approaches to control was held at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP) at New Orleans,LA, USA, during 10–14 August 2003. The workshop was organized and chaired by J.E. Miller and P.J. Waller. Novel or alternative approaches to control have been the focus of research (basic and applied) in many parts of the world. The objective of the workshop was to discuss where we have been and what direction(s) appears to be viable for both the short and long term future. In the long term, all represented regions at the workshop have promulgated programs where breeding for resistance may be the best approach as genes for resistance can be fixed in host populations. However,it does take many years to achieve results and the question of tradeoff concerning alteration of production traits needs further evaluation. Vaccination, especially against Haemonchus contortus,has been a thrust of laboratories in Scotland and Australia where natural “hidden gut” antigens have shown promise, but recombinant products have yet to be developed. In Europe, North and South America, Australia, South Africa and Asia, biocontrol using the nematode-trapping fungus Duddingtonia flagrans has been shown to be effective under experimental conditions, but some field evaluations have been disappointing. Most recently, the FAMACHA system was developed in South Africa. This system is directly and immediately applicable to all regions where H. contortus is a problem. Although not a new or novel approach, copper-oxide wire particles have been revived as a means to control H. contortus.Work being done in Europe, North and South America,South Africa and Australia have shown very encouraging results and can probably be considered the best short term approach available. However, caution needs to be considered in sheep to avoid potential copper toxicity problems. Work in New Zealand, Scotland and the US with forages and feeds containing condensed tannins have shown some limited control. Many laboratories have demonstrated that adequate and balanced nutrition programs are also important to maintain mechanisms that combat infections. Overall, no one approach alone is the answer. Approaches that are integrated, including “smart” use of anthelmintics, are necessary.