Recent applied field research activities carried out in tropical Africa.

A review has been undertaken of applied field research in malaria in tropical Africa from 1975 onwards, the aim being to show recent trends and to emphasize the needs for further research in support of malaria control.Studies are grouped according to whether they relate to parasites, vectors, epidemiology, or control. The first group is concerned mainly with the study of the appearance and development of resistance of Plasmodium falciparum to drugs. The second group deals with vector bionomics and the differentiation of various species in the Anopheles gambiae complex. Next come descriptive and analytical surveys and studies on the characterization of malaria as a health and social problem, the importance of some congenital factors, and immunological aspects of the disease. Studies on control comprise the use of drugs, insecticides, and biological methods.The main achievements of research to date have been to improve knowledge of the distribution of chloroquine resistance, which is still mainly confined to East Africa; to clarify the distribution of the components of the A. gambiae complex, even in the formerly known A. gambiae sensu stricto; and to provide indications that the use of mass chemosuppression may favour drug resistance and reduce the malaria antibodies in the population, although the clinical significance of the latter needs to be elucidated.Among the domains considered important for future research are the monitoring of drug sensitivity, not only to 4-aminoquinolines but also to alternative drugs; the determination of optimum drug regimens in various circumstances and population groups; studies on malaria mortality, morbidity, and immunity as related to the use of drugs; the study of the epidemiological importance of various vector species, their behaviour and amenability to control; and feasibility studies on various methods of control in the context of the primary health care settings, including cost-effectiveness and cost-benefit determination.