Cholera is an acute diarrheal infection and remains a global public health problem across many countries and regions of the developing world. Changing climatic conditions and recurrent natural disasters make the population of Bangladesh exceptionally vulnerable to both epidemic and endemic cholera. Heavily populated areas in the Bengal Delta present with both seasonal cholera occurrence (typically epidemic) as well as persistence over the entire year (endemic). While the bacterium cannot be eradicated, environmental conditions that helps it survive, thrive, and persist in the local aquatic ecosystems and the underlying hydroclimatic drivers can be assessed using appropriate earth observations (Colwell, 1996; Akanda et al. 2011; Jutla et al. 2013).
Studies have linked this disease burden to two seasonal transmission cycles driven by regional coastal and terrestrial geophysical processes (Akanda et al., 2013). Severe water scarcity during the prolonged dry season (November through April) affects water access and quality in inland freshwater bodies as well as the salinity and pathogen concentration in coastal rivers and reservoirs. Analysis shows that a majority of the vulnerable population is willing to change its preferred water collection methods or sanitation and hygiene habits during these high-risk periods if given advance warning. However, limited information and resource constraints often preclude people from taking protective action (Aziz et al., 2015; 2021)
The CholeraMap project is designed to provide cholera early-warning risk maps for the Matlab region in Bangladesh through direct dissemination of cholera risk maps to grass-root workers and end-users, or the people of rural Matlab. The derivation of these risk maps using a range of NASA satellite observations, including precipitation data from the Global Precipitation Measurement mission, and air and ocean temperatures from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Terra and Aqua satellites have been discussed in Akanda et al. (2018).
The app will be used by residents of this region in cooperation with project personnel in charge of developing and facilitating this project. In order to be able to use this free mobile app, the users have to register with a ‘Name’ and a unique 'RID’ number, given to them by project personnel.
This mobile application is designed to disseminate disease early-warning (risk maps and geospatial detailed risk information) directly to users in Matlab, Bangladesh at the grass-root level. The spatial resolution of the risk maps will be 1 km x 1 km grid cells, and the risk will be communicated through three risk categories (High, Medium, and Low). Depending on the risk levels in each grid cell, corresponding water usage and disease safety measures will also be delivered through the app. An accompanying field survey component of the project will use this app to collect information on app usage, changes in water usage behavior, and disease incidence rates. Using app and survey data, an avoided damages approach will quantify the value of cholera early warning that uses satellite-derived disease risk predictions.
We expect that the early warning system will create additional incentives for the at-risk population in Bangladesh to alter their water and sanitation practices in response to cholera risk (Akanda et al. 2012). We understand that these practices and associated water usage and storage behaviors are dependent on the spatio-temporal patterns of water availability, the monsoon season and the occurrence of water-related hazards such as droughts or floods in the region.
This work improves decision making at two levels. First, the risk predictions allow households to make decisions about the types of behaviors in which they should engage, and the level of their investments, based on better information about the cholera risk level they face. Providing households with additional, high-quality information regarding the nature of cholera risk should improve their averting decisions. Second, by analyzing household response to the information provided and valuing the response using an averted damages approach, this work provides valuable insights for policymakers to determine the types of investments—both in terms of magnitude and focus—that should be made in working to prevent and reduce cholera damages (Aziz et al. 2021).
The development of this application was funded by a research grant of the VALUABLES Program jointly administered by the Resources for the Future Foundation (RFF) and the National Aeronautics and Space Administration (NASA) Applied Sciences Program. This challenge grant was awarded as part of the GABS (Grants for Assessing Benefits of Satellites) initiative in 2020 to quantify the benefits of using satellite data in decision making that improve socioeconomic outcomes benefitting people and the environment.
This application was developed at the University of Rhode Island in collaboration with Moravian College, Pennsylvania State University and Virginia Tech University. The investigators are:
Sonia Aziz, Moravian College (Project PI)
Akanda, A.S., S. Aziz, A. Jutla, A. Huq, M. Alam, G.U. Ahsan, and R.R. Colwell (2018), Satellites and cell phones form a cholera early-warning system, Eos, 99, https://doi.org/10.1029/2018EO094839
Akanda, A.S., A. Jutla, D. Gute, T. Evans, and S. Islam (2012), Reinforcing cholera intervention through prediction-aided prevention, Bull. World Health Organ., 90(3), 243–244, https://doi.org/10.2471/BLT.11.092189
Akanda, A.S., Jutla, A.S., Alam, M., De Magny, G.C., Siddique, A., Sack, R.B., Colwell, R.R., Islam, S. (2011). Hydroclimatic Influences On Seasonal And Spatial Cholera Transmission Cycles: Implications For Public Health Intervention In The Bengal Delta. Water Resources Research, 47(3). https://doi.org/10.1029/2010WR009914
Aziz, S.N., et al. (2015), Parental decisions, child health and valuation of avoiding arsenic in drinking water in rural Bangladesh, J. Water Health, 13(1), 152–167, https://doi.org/10.2166/wh.2014.213
Aziz, S., Pakhtigian, E.L., Akanda, A.S., Jutla, A., Huq, A., Alam, M., Ashan, G.U. and Colwell, R.R. (2021). Does improved risk information increase the value of cholera prevention? An analysis of stated vaccine demand in slum areas of urban Bangladesh. Social Science & Medicine, 272, p.113716. https://doi.org/10.1016/j.socscimed.2021.113716
Colwell, R. R. (1996). Global climate and infectious disease: the cholera paradigm. Science, 274 (5295), 2025-2031. DOI: 10.1126/science.274.5295.2025
Jutla, A.S., Akanda, A.S., & Islam, S. (2013). A Framework For Predicting Endemic Cholera Using Satellite Derived Environmental Determinants. Environmental Modelling And Software, 47, 148–158. http://doi.org/10.1016/J.Envsoft.2013.05.008