Table 4 Synthesis of remote sensing contribution for schistosomiasis risk profiling
From: Risk profiling of schistosomiasis using remote sensing: approaches, challenges and outlook
| Â | Factor impacting on disease transmission | Remote sensing (proxy) variable | Ecological impact |
|---|---|---|---|
Parasite | Water body | Near and middle infrared reflectance | Hatching of eggs; infection of snail and human host |
Water temperature | Thermal infrared (emissivity) | Length of prepatent period; activity, survival and infection rate | |
Water flow velocity | Topography: slope angle, curvature | Determination of maximal cercarial density; passive transport of parasite | |
Predators | NA | Reduction of parasite population | |
Sunlight | Shaded habitats (tree coverage) | Reduction of parasite population | |
Pathogenicity | NA | Severity of disease in humans | |
Species | NA | Different efficiency of snail infection | |
Snail | Water body | Near and middle infrared reflectance | Fundamental habitat of snail to maintain a population |
Water temperature | Thermal infrared (emissivity) | Fecundity, mortality and rate of reproduction | |
Water flow velocity | Topography: slope angle, curvature | Determination of snail density; passive transport of snail; food availability | |
Vegetation | Visible and near infrared reflectance | Food supply; surface for oviposition; increase of dissolved oxygen | |
Substratum | NA | Abundance of snails in water body | |
Water depth | Visible and near infrared reflectance | Abundance of snails in water body | |
Stability of water level | Temporal dynamic of water body | Abundance of snails in water body | |
Rainfall | Cloud thickness and temperature | Creation of temporary snail habitats; modification of water flow velocity; supports contamination of water | |
Turbidity | Visible and near infrared reflectance | Reproduction cycle of snails | |
Water chemistry/quality | NA | Abundance of snails in water body | |
Sunlight | Shaded habitats (tree coverage) | Abundance and activity of snails | |
Predators, parasites and pathogens | NA | Reduction of snail population | |
Species | NA | Susceptibility to parasite and cercarial productivity | |
Human | Water contact behaviour | NA | Exposure to parasite infested water; contamination of surface waters |
Gender | NA | Determinant of water contact activities (culturally variable) | |
Age | NA | Related to degree of exposure and level of immunity | |
Immunity | NA | Resistance to reinfection can be developed following previous infections | |
Ethnic origin | NA | Susceptibility to infection | |
Religion | NA | Religious practices may affect patterns of water use | |
Socioeconomic status | NA | Standard of hygiene; access to protected water supply; ability to cope with disease | |
Migration | NA | Modification of spatial distribution of disease | |
Occupation | NA | Work related to water increases exposure | |
Location of the house | Settlement mapping | Exposure of population to potential disease transmission sites | |
Prevention/control measures | NA | Modification of spatial pattern of disease transmission |