THE EFFICIENCY OF PATCH SAMPLING FOR DETERMINATION OF RELATIVE TICK BURDENS IN COMPARISON WITH TOTAL TICK COUNTS

Quantitative data on host tick burdens are fundamental for the initiat ion of control strategies and effective management of wildlife populat ions, but the methods of live sampling employed for domestic animals a re unsuitable for sampling wild animals. Despite advances in the use o f destructive methods (the scrub and digestion techniques) to obtain m easures of the total tick burden on wildlife, these methods are too in volved for many field workers, who often need only measures of relativ e tick burden. Recently, patch sampling methods have been introduced w hereby only certain predilection sites are sampled, the presumption be ing that the number of ticks collected gives an indication of the rela tive degree of infestation. We examined the validity of patch sampling as a measure of relative tick burden by comparing adult ticks collect ed from the ears, head, neck, foreleg and perianal region of impala (A epyceros melampus) with total tick burdens of the same animals derived from the digestion technique. Adult ticks from patch sampling were po sitively and significantly correlated with total adults and total tick s (larvae, nymphs, and adults) on impala, with ticks patch sampled fro m the neck showing the highest correlation with the total tick burden. Comparison of relative tick loads from patch sampling with absolute t ick loads from digestion for three classes of impala (females, bachelo r males and territorial males) gave qualitatively similar results. We conclude that, when measures of relative tick load are sufficient and destructive sampling is not feasible, patch sampling can provide relia ble information on relative tick burdens that are positively correlate d with the total tick burden.