Sampling strategies to detect anthelmintic resistance: the perspective of human onchocerciasis.

The large-scale use of mass drug administration in human helminthiases control has raised awareness that anthelmintic resistance could develop. This has motivated an increasing number of studies to investigate changes in genetic structure of parasite populations undergoing treatment. For these studies to reflect accurately the current situation, parasitologists need to consider the sampling schemes they employ. In this article, we use mathematical models to discuss issues such as which hosts to examine, on which parasite life stage(s) to focus, and when after treatment to sample to quantify the presence and frequency of genetic markers of treatment-induced selection or drug resistance.