[Limits of impregnated bednets for malaria control in tropical Africa]

There is no direct relationship between malaria transmission intensity and the burden of the disease. Due to acquired immunity there is little difference both in potential malaria mortality and the total number of malaria attacks over an entire lifetime between individuals bitten by infected anophelines a few times a year and those bitten by infected anophelines hundreds of times a year: It is only for low levels of transmission that there exists a relation between the entomological inoculation rate, the disease incidence rate and potential malaria mortality. Even if impregnation by insecticides improves bednet efficiency the vector capacity of Anopheles gambiae, An. arabiensis and An. funestus is too high for impregnated bednets to be an efficient means of malaria control in most rural areas of tropical Africa. The reduction of malaria mortality observed during several pilot projects is probably a short term effect. We propose focussing vector control on low and/or unstable malaria transmission areas, i.e. where these activities have proved crucial for the reduction or even eradication of malaria. In moderate or high transmission areas, better access to health care and improvement of malaria case management are currently the only means for reducing durably the burden of malaria.