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SummaryChloroquine resistance was first detected in Kenya in 1978 and escalated during the 1980s. Chloroquine remained the treatment of choice for uncomplicated malaria infections until revised guidelines were launched in 1998 despite a plethora of scientific evidence on failure. This review analyses the range and quality of the evidence base that was used to change the drug policy in Kenya from chloroquine to SP and examines the process of consensus building and decision making. Our review illustrates the difficulties in translating sensitivity data with gross geographical, temporal and methodological variations into national treatment policy. The process was complicated by limited options, unknown adverse effects of replacement therapies, cost, as well as limited guidance on factors pertinent to changing the drug policy for malaria. Although Ͼ 50% of the studies showed parasitological failures by 1995, there was a general lack of consensus on the principles for assessing drug failures, the inclusion criteria for the study subjects and the relative benefits of parasitological and clinical assessments. A change in international recommendations for assessment of drug efficacy in 1996 from parasitological to clinical response further perplexed the decisions. There is an urgent need for international standards and evidence-based guidelines to provide a framework to assist the process by which decision-makers in malaria-endemic countries can make rational choices for antimalarial drug policy change.keywords chloroquine resistance, Kenya, drug policy correspondence Professor Robert Snow, KEMRI/Wellcome Trust Programme,

This review highlights the progress and current status of remote sensing (RS) and geographical information systems (GIS) as currently applied to the problem of Plasmodium falciparum malaria in sub-Saharan Africa (SSA). The burden of P. falciparum malaria in SSA is first summarized and then contrasted with the paucity of accurate and recent information on the nature and extent of the disease. This provides perspective on both the global importance of the pathogen and the potential for contribution of RS and GIS techniques. The ecology of P. falciparum malaria and its major anopheline vectors in SSA in then outlined, to provide the epidemiological background for considering disease transmission processes and their environmental correlates. Because RS and GIS are recent techniques in epidemiology, all mosquito-borne diseases are considered in this review in order to convey the range of ideas, insights and innovation provided. To conclude, the impact of these initial studies is assessed and suggestions provided on how these advances could be best used for malaria control in an appropriate and sustainable manner, with key areas for future research highlighted.

The use of insecticide-treated bednets (ITBNs) has been shown to be effective in reducing mortality and morbidity from malaria. However, there is mixed evidence as to whether or not community-wide use of ITBNs engenders a 'mass effect', such that those not sleeping under bednets are offered protection from widespread ITBN use in the area in which they live. We have analysed data collected in Kilifi, Kenya, from a cohort of children followed from birth to investigate how the degree of net usage in the locality of a child affects the risk of developing malaria. This effect was explored using a Cox proportional hazards model. For those not using ITBNs, we found that an increasing level of ITBN usage within the area surrounding each child was associated with a decreasing risk of developing malaria, thus providing evidence in support of a mass community effect. The size and significance of this effect were found to decrease as non-overlapping areas of increasing distance away from a child's home were considered. The effect was significant for areas at distances of up to 1.5 km away from each child.

Reemergence of epidemics in tea plantations will likely result in antimalarial-drug resistance.