Reducing the burden of malaria in different eco-epidemiological settings with environmental management: a systematic review.

The public health and economic significance of malaria is enormous, and its control remains a great challenge. Many established malaria control methods are hampered by drug resistance and insecticide-resistant vectors. Malaria control measures built around environmental management are non-toxic, cost-effective, and sustainable. However, there has been no comprehensive review of the literature or meta-analysis examining the effect of these interventions. We therefore did a systematic literature review and identified 40 studies that emphasised environmental management interventions and reported clinical malaria variables as outcome measures. Of these 40 studies, environmental modification (measures aiming to create a permanent or long-lasting effect on land, water, or vegetation to reduce vector habitats--eg, the installation and maintenance of drains) was the central feature in 27 studies, environmental manipulation (methods creating temporary unfavourable conditions for the vector--eg, water or vegetation management) in four, and nine quantified the effect of modifications of human habitation. Most of the studies (n=34, 85%) were implemented before the Global Malaria Eradication Campaign (1955-69), which mainly relied on indoor residual spraying with dichlorodiphenyltrichloroethane (DDT). In 16 studies that applied environmental modification and in eight studies on modification of human habitation, the risk ratio of malaria was reduced by 88.0% (95% CI 81.7-92.1) and 79.5% (95% CI 67.4-87.2), respectively. We conclude that malaria control programmes that emphasise environmental management are highly effective in reducing morbidity and mortality. Lessons learned from these past successful programmes can inspire sound and sustainable malaria control approaches and strategies.