Refugia som metod för att minska utvecklingen av anthelmintikaresistens hos får

Sammanfattning: Anthelmintic resistance is a major problem in sheep husbandry all over the world. One way toslow down the development of anthelmintic resistance is to keep part of the parasitepopulation in refugia (unexposed to drugs) which will maintain the genes for susceptibilitywithin the population. Climate, type of parasite and drenching regimes effect the size of therefugia. Dilution of resistant with susceptible parasites, targeted treatment and targetedselective treatment are all management strategies that employ refugia. Dilution is possible butcomplicated. Targeted treatment means not drenching when there are few parasites in refugiaas this selects for resistance. Targeted selective treatment means only drenching animals thatneed treatment. FAMACHA© has turned out to be an effective method to pick out theanimals which suffer from an infection with H. contortus. To use daily weight gain as anindicator of which animals to treat is effective but costly. Five point check© needsdevelopment and evaluation to be a useful alternative. The methods need to be simple, cheapand functional in order to be used by farmers. There is also a need for foregoers among thefarmers that can show the others that the new methods work and do not lead to productionloss and a worsened animal health. Refugia delay the development of anthelmintic resistance– it does not stop it.