Prevention and control of malaria epidemics.

Malaria epidemics have recently occurred in many areas of the world, particularly in the irregular fringe, along the limits of distribution of malaria endemicity, whether the limiting factors are temperature (latitude or altitude) or relative humidity (deserts), which were the scene of the major epidemics of the past. A review is made of the current approaches to epidemic prevention and control in line with the global malaria control strategy, of which it constitutes an essential element. The different components are discussed, including the identification and study of epidemic prone areas, the search for indicators of epidemic risk, their monitoring, and the early detection and control of actual epidemics. The potential implementation of preventive and control activities depends, nevertheless, on the degree of preparedness of the health services to detect alarm signals, the real time left for action and their capacity of implementation within that time. Recent developments in geographical information systems (GIS) and satellite derived meteorological information offer most useful tools for precise and timely epidemic forecasting, although it should be recognised that such information is only useful if based on a real understanding of their local significance. There remains an urgent need to develop and support local capabilities for the ground truthing of satellite information and for translating it into preventive and control actions.