A water marker monitored by satellites to predict seasonal endemic cholera

Abstract

The ability to predict an occurrence of cholera, a water-related disease, offers a significant public health advantage. Satellite based estimates of chlorophyll, a surrogate for plankton abundance, have been linked to cholera incidence. However, cholera bacteria can survive under a variety of coastal ecological conditions, thus constraining the predictive ability of the chlorophyll, since it provides only an estimate of greenness of seawater. Here, a new remote sensing based index is proposed: Satellite Water Marker (SWM), which estimates condition of coastal water, based on observed variability in the difference between blue (412 nm) and green (555 nm) wavelengths that can be related to seasonal cholera incidence. The index is bounded between physically separable wavelengths for relatively clear (blue) and turbid (green) water. Using SWM, prediction of cholera with reasonable accuracy, with at least two month in advance, can potentially be achieved in the endemic coastal regions.

Environmental Factors Influencing Epidemic Cholera

“…[47][48][49][50] For example, if the strong likelihood of a new cholera epidemic in Port-Au-Prince is known two months in advance, such a warning will enable health authorities in Haiti to prepare for and minimize the impact of the elevated incidence of cholera in potentially vulnerable localities by implementing carefully planned prevention approaches. A reliable and robust cholera prediction model coupled with a spatio-temporal population vulnerability or risk map of potential cholera outbreaks will allow: Vaccination of vulnerable demographic groups (children and elders) in advance, mobilization of expert resources (physicians, nurses, and public health workers), allocation of material (water purification equipment and oral hydration therapy, implementation of water, sanitation, and hygiene (WASH) regulations and practices in regions at risk of outbreaks, and education and awareness campaigns for epidemic warnings and WASH compliance.…”

Predictive Time Series Analysis Linking Bengal Cholera with Terrestrial Water Storage Measured from Gravity Recovery and Climate Experiment Sensors

“…Previous research linking cholera with hydroclimatic processes have convincingly shown that, to understand a cholera in the Bengal Delta, seasonality of the disease must be separately investigated. 3,11,34 In summary, Figure 6 presents a schematic hydroclimatological cascade linking cholera with GRACE sensor data in which low and high flows can be interpreted as creating favorable conditions for growth of cholera bacteria but each for different reasons. Both high and low river flows were found to be statistically related with a lead time of at least 2 months for autumn and spring cholera peaks.…”

Population Vulnerability to Biannual Cholera Outbreaks and Associated Macro-Scale Drivers in the Bengal Delta

“…For future research, better health surveillance data and higher resolution climate and hydrologic data would be invaluable to understand these processes in more detail. [25][26][27] A cholera warning system based on the geographic specificity of salinity and flood signatures holds the promise of predicting the future intensity and location of epidemics. Such a system can potentially provide public health authorities with spatially specific warnings regarding the extent and magnitude of impending outbreaks, especially in slum areas lacking in necessary water infrastructure, to alert medical personnel and start implementing preventive measures.…”