Journal Article > CommentaryFull Text
Am J Trop Med Hyg. 2017 June 1; Volume 96 (Issue 6); 1270-1273.; DOI:10.4269/ajtmh.16-0427
Lessler J, Azman AS, McKay H, Moore SM
Am J Trop Med Hyg. 2017 June 1; Volume 96 (Issue 6); 1270-1273.; DOI:10.4269/ajtmh.16-0427
The importance of spatial clusters, or "hotspots," in infectious disease epidemiology has been increasingly recognized, and targeting hotspots is often seen as an important component of disease-control strategies. However, the precise meaning of "hotspot" varies widely in current research and policy documents. Hotspots have been variously described as areas of elevated incidence or prevalence, higher transmission efficiency or risk, or higher probability of disease emergence. This ambiguity has led to confusion and may result in mistaken inferences regarding the best way to target interventions. We surveyed the literature on epidemiologic hotspots, examining the multitude of ways in which the term is used; and highlight the difference in the geographic scale of hotspots and the properties they are supposed to have. In response to the diversity in the term's usage, we advocate the use of more precise terms, such as "burden hotspot," "transmission hotspot," and "emergence hotspot," as well as explicit specification of the spatiotemporal scale of interest. Increased precision in terminology is needed to ensure clear and effective policies for disease control.
Journal Article > ResearchFull Text
Lancet. 2018 May 1; Volume 391 (Issue 10133); DOI:10.1016/S0140-6736(17)33050-7
Lessler J, Moore SM, Luquero FJ, McKay H, Grais RF, et al.
Lancet. 2018 May 1; Volume 391 (Issue 10133); DOI:10.1016/S0140-6736(17)33050-7
Cholera remains a persistent health problem in sub-Saharan Africa and worldwide. Cholera can be controlled through appropriate water and sanitation, or by oral cholera vaccination, which provides transient (∼3 years) protection, although vaccine supplies remain scarce. We aimed to map cholera burden in sub-Saharan Africa and assess how geographical targeting could lead to more efficient interventions.
Journal Article > ResearchFull Text
Proc Natl Acad Sci U S A. 2017 April 10; Volume 114 (Issue 17); 4436-4441.; DOI:10.1073/pnas.1617218114
Moore SM, Azman AS, Zaitchik BF, Mintz ED, Brunkard J, et al.
Proc Natl Acad Sci U S A. 2017 April 10; Volume 114 (Issue 17); 4436-4441.; DOI:10.1073/pnas.1617218114
The El Niño Southern Oscillation (ENSO) and other climate patterns can have profound impacts on the occurrence of infectious diseases ranging from dengue to cholera. In Africa, El Niño conditions are associated with increased rainfall in East Africa and decreased rainfall in southern Africa, West Africa, and parts of the Sahel. Because of the key role of water supplies in cholera transmission, a relationship between El Niño events and cholera incidence is highly plausible, and previous research has shown a link between ENSO patterns and cholera in Bangladesh. However, there is little systematic evidence for this link in Africa. Using high-resolution mapping techniques, we find that the annual geographic distribution of cholera in Africa from 2000 to 2014 changes dramatically, with the burden shifting to continental East Africa-and away from Madagascar and portions of southern, Central, and West Africa-where almost 50,000 additional cases occur during El Niño years. Cholera incidence during El Niño years was higher in regions of East Africa with increased rainfall, but incidence was also higher in some areas with decreased rainfall, suggesting a complex relationship between rainfall and cholera incidence. Here, we show clear evidence for a shift in the distribution of cholera incidence throughout Africa in El Niño years, likely mediated by El Niño's impact on local climatic factors. Knowledge of this relationship between cholera and climate patterns coupled with ENSO forecasting could be used to notify countries in Africa when they are likely to see a major shift in their cholera risk.