Abstract:
Anthelmintic resistance is recognised as a major problem affecting small ruminant
production worldwide and now threatens the sustainability of many of these systems. One
method that has been proposed to prolong the efficacy of our current anthelmintics is the maintenance of a parasite population in refugia (unexposed to a drug) which will maintain the genes for susceptibility within the parasite population. Management strategies that employ refugia-based methods include targeted or strategically timed whole flock treatments, targeted selective treatments (TST), whereby only a proportion of the flock is treated at any one time, and the dilution of resistant with susceptible parasites. The ability
to effectively target anthelmintic use relies on the identification of those animals that will most benefit from treatment. This review explains the concept of refugia, describes the role of refugia-based approaches to the management of anthelmintic resistance and reviews the markers that have been studied as indicators for TSTs as well as the
implementation of refugia-based strategies. Recent results suggest that targeting
anthelmintic treatment on the basis of anaemia, milk production and liveweight gain
may offer a means of reducing anthelmintic usage whilst still maintaining animal
performance.
