Toward Cholera-Free Nations: How NASA Satellites Help Track Pathogenic Vibrios

Data on disease prevalence and infectious pathogens is sparingly collected/available in region(s) where climatic variability and extreme natural events intersect with population vulnerability (such as lack of access to water and sanitation infrastructure). Therefore, traditional time series modeling approach of calibration and validation of a model is inadequate. Despite significant advances in etiology of pathogenesis, we are still not able to predict when and where an outbreak of infection will occur. Lack of civil infrastructure (access to clean water and sanitation) increases risk of interaction between infectious pathogens and human population. Cholera, a deadly waterborne disease is transmitted by drinking water contaminated with Vibrio cholerae. The bacterium is autochthonous to aquatic system and hence cannot be eradicated from the environment. Occurrence and growth of the bacteria is linked to modalities of climatic processes, and hence it is possible to develop mathematical models to determine risk of infection in human population. Here, using satellite derived data on precipitation, temperature, population density and available water and sanitation infrastructure, we will show that the model predicted high risk of cholera, at least four weeks in advance, in Yemen in June 2017. A new real time algorithm using only satellite remote sensing data was developed and implemented in Yemen for year 2018. We will also present a case study on practical applicability of the algorithm.