Molecular markers as indicators of antimalarial drug failure rates.

Several mutations have been identified in Plasmodium falciparum that cause, or contribute to, drug resistance. It is relatively easy to measure their prevalence in human blood samples, so they are often used to infer drug failure rates, clinical and parasitological, that will occur in the human population. One current method of making this inference is through the use of genotypic resistance and genotypic failure indices. These indices are rather sensitive to background drug failures rates (i.e. failures not caused by the mutation), to mutation prevalence, and to the genetic background in which the marker occurs. Extreme care should therefore be taken in the construction and interpretation of these indices.