For a long time now there has been concern about the possibility of an approaching disaster as chloroquine resistance spreads across Africa. A paper by Jean Francois Trape and his colleagues1 should jolt anyone who was beginning to think that the issue had been oversold. Trape and colleagues have examined mortality patterns in three areas of Senegal over a period of 11 years, during which chloroquine resistance first emerged there. The areas differ in malaria endemicity and health-care provision but in all of them essentially the same methods were used for monitoring cause-specific mortality. All three areas have shown a striking rise in malariaspecific mortality. In each case the rise has begun exactly at the time that chloroquine resistance was first noted. The risk of death from malaria in two of the areas—one with high transmission of malaria and the other low to moderate—more than doubled. In the third area, Mlomp, a moderate transmission area with unusually good health care, the risk of malaria deaths in children aged under 5 years rose eight-fold. The researchers discount other changes, whether in climate, other diseases, or human behaviour, as a reason for these rises. Although the result from any one of the areas would be cause for concern, the strength of the paper is the consistent pattern across the three sites.

Some people will say that the findings are hardly surprising. After all, if there is a common disease that may be fatal, and the drug for its treatment is withdrawn, the consequences are predictable. The problem has been that the impact of chloroquine resistance has been difficult to measure. Most malaria deaths in Africa happen “out of sight” in rural areas scattered over a massive continent. In such places accurate measurement of overall mortality rates is difficult enough and that of cause-specific rates almost impossible. Many epidemiologists have been convinced that malaria mortality has been rising in East Africa. Trape and colleagues have shown that the process is already well advanced in West Africa, where levels of chloroquine resistance are much lower. There has been much, rather inconclusive, debate on levels of resistance at which countries should consider a switch to alternative first-line drugs. The data from the Trape study suggest that radical review of this issue is urgently required. The data also highlight the fact that, for Africa, case treatment is central to the control of malaria. Experience in Mlomp is especially instructive. Here an unusually comprehensive health service provided by Catholic nuns has greatly improved child survival. All-cause mortality among children aged under 5 years had dropped to around a third of that in the other sites and malaria-specific mortality to around a tenth. Malaria deaths had accounted for only 2% of all deaths, but since the emergence of chloroquine resistance, this percentage has risen to 25%, a proportion similar to that in the other two areas. However, at 5· 5/1000 per year, the absolute number of deaths from malaria is still under half that of the other areas, even though chloroquine resistance has reached higher levels in Mlomp. The implication is that choroquine properly used is still preventing deaths and that the situation can only get worse.