Global hotspots of disasters and waterborne disease outbreaks

In 2019, cyclones Idai and Kenneth hit Mozambique’s coast only six weeks apart. A state of emergency was declared by the World Health Organisation (WHO) due to the outbreak of cholera and other infectious diseases. This was exacerbated by a lack of sanitation and access to clean drinking water, especially in densely populated, poorer regions. After Idai, financial resources were already strained, impairing the response to the impacts of subsequent cyclone Kenneth. The continued displacement of people and ongoing disruption of basic services after Kenneth contributed to another cholera outbreak. 

In recent years, society faced immense challenges resulting from the increasing complexity of disaster risk. As the example demonstrates, the impacts of consecutive disasters are often exacerbated by the consecutive nature of the hazards themselves. Several recent international agreements have called upon the disaster risk science community to move away from assessing the risk from hazards one-by-one and to improve our understanding of temporal dynamics of disaster risk. Subsequently, in past years, we have seen a rise in multi-(hazard) risk studies trying to understand some of these complexities conceptually and statistically. However, these studies do not consider the consecutive occurrence of disease outbreaks following hazards.  

In this research, we use the Myriad-HESA database (Claassen et al., 2023) to link historic disasters caused by natural hazards with historic waterborne diseases outbreaks. We develop spatiotemporal footprints of disease outbreaks based on open-source databases of historic disease outbreaks. We then apply Myriad-HESA using the eleven single hazards already included in the database and overlay them with the disaster outbreaks data. This allows us to map hotspots of overlapping events but also to assess events with a time window (allowing for a temporal lag between disasters and subsequent disease outbreaks). Our findings allow practitioners to respond more accurately and promptly depending on the local situation.