Transmission factors in malaria epidemiology and control in Africa.

Genetic and environmental components of factors contributing in malaria transmission are reviewed. Particular attention is given to density dependent regulation of vector populations in relation to the survival rate of anophelines. The expectation of vector control activities are different according to the epidemiological characteristics of malaria, mainly its stability. In areas with perennial and high transmission (stable malaria) vector control could reduce malaria related morbidity and mortality, without any effect on the endemicity. However this need further investigations. In areas where the transmission period is very short (unstable malaria), vector control will have an important impact on the disease and on the endemicity. Control projects using indoor spraying with insecticide and impregnated bed nets are discussed.