Working without a blindfold: the critical role of diagnostics in malaria control

Abstract

Diagnostic testing for malaria has for many years been eschewed, lest it be an obstacle to the delivery of rapid, life-saving treatment. The approach of treating malaria without confirmatory testing has been reinforced by the availability of inexpensive treatment with few side effects, by the great difficulty of establishing quality-assured microscopy in rural and resource-poor settings, and by the preeminence of malaria as a cause of important fever in endemic regions. Within the last decade, all three of these factors have changed. More expensive artemisinin combination therapy (ACT) has been widely introduced, simple immunochromatographic tests for malaria have been developed that can be used as an alternative to microscopy by village health workers, and recognition of the health cost of mismanaging non-malarial fever is growing. In most of the world a small fraction of fever is due to malaria, and reflex treatment with ACT does not make medical or economic sense. Global malaria control efforts have been energized by the availability of new sources of funding, and by the rapid reduction in malaria prevalence in a number of settings where bed nets, indoor residual spraying with insecticides, and ACT have been systematically deployed. This momentum has been captured by a new call for malaria elimination. Without wide implementation of accurate and discriminating diagnostic testing, and reporting of results, most fever will be inappropriately managed, millions of doses of ACT will be wasted, and malaria control programmes will be blindfolded to the impact of their efforts.

Figure 1

High mortality at 10 Tanzanian hospitals among patients admitted with severe disease and treated for malaria. (Adapted from [22]).

Figure 2

Scaled-up use of ACT and RDTs in India, in millions.

Figure 3

As malaria moves towards elimination and funding agencies require clearer feedback on progress, malaria reporting will need to move towards more real-time and geographically-refined incidence reporting. This will require the vast majority of malaria-like fevers to be diagnosed using parasite-based diagnosis to confirm presence or absence of malaria parasites. At present, malaria reporting is at a relatively gross level. (a) Map of estimated malaria incidence per 1000 population, 2006 (Source: World Malaria Report, 2008), compared with some other diseases with well-developed case finding and reporting systems. (b) Map of wild poliovirus infections detected 29 Oct 2007 to 28 Oct 2008.