Climate and infectious diseases

Climate plays an important role in the transmission of many infectious diseases; it not only determines spatial and seasonal distributions, but influences inter-annual variability, including epidemics, and long-term trends. This paper collates published scientific literature on climate and 20 infectious diseases that cause considerable morbidity and mortality worldwide. It highlights what has been done to date, identifies gaps and assesses the role of climate information in improving health system performance, especially in developing countries. Parasitic, viral and bacterial diseases are discussed in the light of climate impacts on classified according to geographic distribution, seasonality, interannual variability, or climatic shifts. Study methods range from simple comparisons in seasonality, to detailed risk analyses, predictive models and early warning systems for epidemics. Malaria and dengue were found to be the most researched diseases with respect to climate, followed by meningococcal meningitis, schistosomiasis, rotavirus, and leishmaniasis. Studies on diseases with long development periods tended to focus on spatial patterns for the creation of risk maps while acute diseases focused interannual variability and the creation of climate-driven early warning systems. An emerging area identified in this review is the potential for climate information to improve the quality of intervention impact assessment where diseases are climate sensitive. We note that despite an extensive literature for some diseases very little research has been done in the countries with the highest number of child deaths and under-five mortality rates. This review provides a platform from which to launch future research and policy development in relation to climate-sensitive disease, and suggests that vulnerable countries should be the priority focus of this effort.