Mapping the Risk and Distribution of Epidemics in the WHO African Region

Executive Summary

Disease epidemics result in substantial ill health and loss of lives and therefore pose a threat to global health security, undermine socio-economic lives and destabilize societies. Disease surveillance is a critical component in detecting and effectively responding to epidemics to minimize loss of live and their disruptive consequences. Carefully assembled surveillance data at the highest possible spatial resolutions also permit the understanding of the burden of epidemics, their co-occurrence and the key biological, ecological, economic, health system and governance determinants. It is for this purpose that the WHO-AFRO has commissioned this report. The overarching objective was to develop a comprehensive spatially defined database of outbreaks and epidemics and delineate the ecological zones of diseases that are classified as Public Health Emergency of International Concern (PHEIC) according the International Health Regulations (IHR) 2005 and malaria.

The main tasks included the assembly of an inventory of all epidemics reported in Africa from 1970-2016 characterised by date of occurrence, length of epidemic and magnitude and district of occurrence; definition of ecological zones of PHEIC diseases and malaria; the assembly of data on important socio-economic, health systems and environmental correlate and an basic statistical analysis of their relationship with occurrence and frequency of epidemics and outbreaks.
Through this study, several products have been developed including time series graphs of outbreak and epidemic occurrence by country, maps of the ecologies of the PHEIC diseases and epidemics, the distribution of these diseases by district. Overall, over 1730 outbreaks/epidemics have been reported in the WHO African region in the period 1970 to 2016. Because the outbreak/epidemic thresholds of the different diseases vary and the actual case data is incomplete, it is difficult to compare which diseases are most prevalent or pervasive. However, in terms of frequency of events, cholera, the arboviruses, measles and meningitis rank the highest. Of the nearly 5250 administrative 2 units analysed in this study, almost each one has reported some form of a disease outbreak in the period 1970-2016, with cholera being the most geographically widespread. The resulting databases are spatially defined and should serve as the basis of subnational inventory of disease outbreaks and epidemics in the region.

Several challenges were encountered in the process of implementing this exercise:

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