Skip to main content

Table 1 Risk factors and fuzzy membership functions used to create risk maps

From: A multi-criteria decision analysis approach to assessing malaria risk in northern South America

Data Source Factor Control points Fuzzy function Rationale
Deforestation Global Forest change [54] Distance (km) 0, 5 Linear ↓ Vectors are found within 5 km of deforested areas
Elevation SRTM 90 m Elevation (m) 500, 1800 J-shaped ↓ Exposure to vectors decrease above 500 m and is non-existent above 1800 m
Population LandScan Population density 2, 50, 100, 150 Sigmoidal ↑↓ Populations between 2 and 150/km2 are sufficient for malaria transmission
Precipitation WorldClim Precipitation (mm) 0, 80 Linear ↑ Precipitation of 80 mm is suitable for vectors for stable transmission to occur [43]
Roads DCW Distance (km) 0, 5 Linear ↓ Transmission occurs within 5 km of roads where blood meals are available
Temperature WorldClim Temperature °C 18, 22, 32, 40 Sigmoidal ↑↓ Sporogony starts at 18 °C and is completed at 22 °C, vector survival decreases above 32 °C and death occurs at 40 °C [43]
TWI SRTM 90 m Soil Saturation (%) 0, 5 Linear ↑ An area requires about 5 % water saturation to serve as breeding site
Urban areas DeLorme, Inc. Distance (km) 1, 10, 20, 30 Sigmoidal ↑↓ Vectors are absent in urban areas but found in the urban periphery
Wetlands WWF Distance (km) 0, 3 Linear ↓ Vectors are found within 3 km of wetlands
  1. Abbreviations and Symbols: SRTM Shuttle Radar Topography Mission, DCW Digital Chart of the World, WWF World Wildlife Fund. The ↑ arrows indicates an increasing function, ↓ a decreasing function and ↑↓ a symmetric function