19 studies that included older children led to an estimate of 587 per 1,000 (on average, about one episode every other year). The median estimate for non-pregnant adults (based on only seven studies) was 107 per 1,000 people each year. Rates in low-transmission and fringe areas were correspondingly lower.
Given the fragmentary statistics on malaria morbidity and mortality, it may seem presumptuous to attempt an assessment of how the spread of resistance to chloroquine and sulfadoxine-pyrimethamine (SP) has affected these measures over the past decades. There is, in fact, little direct information on how the number of cases of malaria has changed in the most endemic areas. What has been documented, however, are stark bellwethers of worsening conditions: a well-documented instance is the malaria epidemic of 1999-2000 in KwaZulu Natal, South Africa, which was a direct result of failing antimalarial drugs—SP had a failure rate of 88 percent. Other factors—increased vector resistance to the pyrethroid insecticides that were introduced in 1996, and the reinvasion of the highly anthropophilic Anopholes funestus vector—further exacerbated this epidemic (Muheki et al., 2003). The introduction of ACTs (and other control measures) brought the epidemic under control. And the question of changes in mortality has been addressed by thorough reviews of the data that do exist, in two major efforts. The first, the long view across the 20th century, used a variety of historical records from the BOMA project (Snow et al., 2001). The other case is an examination of trends in the 1980s and 1990s on a finer scale, contrasting East and West Africa (Korenromp et al., 2003), using the relatively uniform data reported in African Demographic Surveillance Systems (DSS).
The BOMA project provides the best opportunity to chart malaria’s past in Africa, and how drug resistance has affected its course over the final decades of the 20th century. The BOMA project began in 1998 with the aim of assembling in a single database all available evidence on morbidity, disability, and mortality associated with falciparum malaria in Africa, starting as far back as possible. The data come not only from the usual electronic databases, but from hand searches of early, unindexed papers in English and French tropical medicine journals, and a mass of unpublished material from local and regional conference proceedings, libraries, and Ministries of Health records (Snow et al., 2001).
In 2001, Snow and colleagues selected as much information as possible