Reproduction numbers in malaria and their implications.

The malariologist Lewis Wendell Hackett famously observed that, "Like chess, (malaria) is played with a few pieces, but is capable of an infinite variety of situations". This paper discusses one such piece, the Red Queen. Red Queen phenomena arise when an intensification of effort leads to a need for further intensification to maintain the new status quo. Such phenomena represent dangers for current strategies to combat the disease. Understanding reproduction numbers is key to understanding these dangers. In this paper, we show why the variability and dynamics of reproduction numbers is important for analyzing the effects of interventions against malaria. This has importance for both formal modeling of malaria and for planning malaria intervention strategies in the field.