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Table 1 Categorization of exposure risk factors

From: Modelling local areas of exposure to Schistosoma japonicum in a limited survey data environment

Risk factor (weight)

Spatial resolution

Temporal resolution

Data type

Coordinate system

Data source

Hypothetical link

Classification

Ï€ weights

Based upon

Elevation (0.03)

~ 30 m at equator

na

Raster

EPSG:4326

Aster GDEM V2 from USGS

While elevation decreases, the risk of infection increases

High risk: < 900 m

0.70

[32, 51, 56]

Medium risk: 900–2300 m

0.25

Low risk: > 2300 m

0.05

Land use (0.26)

~ 30 m

2-3-2017

Vector

EPSG:4326

OpenStreetMap project

Wet surfaces are more suitable to ahigher risk of infection

Very high risk: wet soils

0.42

[32, 57]

High risk: water bodies

0.29

High and medium risk: Agriculture land and grass

0.16

Medium and low risk: forest and natural areas

0.08

Low risk: barren land

0.02

Very low risk: built land

0.03

Slope (0.13)

~ 30 m at equator

na

Raster

EPSG:4326

Derived from elevation

At more flat surfaces the risk of infection increases

High risk: < 11 degrees

0.70

[49, 51]

Medium risk: 11–30 degrees

0.23

Low risk: > 30 degrees

0.07

Distance to water bodies (0.50)

30 m

2-3-2017

Raster

EPSG:32651

Derived from roads, urban areas, river network and water bodies from the OpenStreetMap project

While distance to water bodies decreases, the risk of infection increases

High risk: < 1000 m

0.74

[51, 52, 58]

Medium risk: 1000–5000 m

0.21

Low risk: > 5000 m

0.05

Snail infection rate (0.06)

na

2015–2016

Vector

EPSG:4326

Derived from recorded surveys

While snail infection rate increases, the risk of infection increases

High risk: > 3.6%

0.65

[23, 24, 30, 31]

Medium risk: 0.5–3.6%

0.28

Low risk: < 0.5%

0.07

  1. Abbreviation: na, not applicable