Table 3 Relationships between key variables and suitability for endemic and epidemic Rift Valley fever.
| Â | Endemic suitability | Epidemic suitability | ||||
|---|---|---|---|---|---|---|
Factor | Shape | Maximum suitability | Minimum suitability | Shape | Maximum suitability | Minimum suitability |
Rainfall | Symmetrical | 750–2000 mm | <50 mm; >3000 mm | Monotonic decreasing | <10 mm | >3000 mm |
Land Surface Temperature | Symmetrical | 40 – 45°C | <25°C; >50°C | Monotonic increasing | >40°C | <25°C |
Elevation | Monotonic decreasing | <10 m | >2500 m | Monotonic decreasing | <10 m | >2500 m |
Distance to major rivers | Monotonic decreasing | <0.1 dec. degrees | > 2.0 dec. degrees | Monotonic decreasing | <0.1 dec. degrees | > 2.0 dec. degrees |
Distance to minor rivers | Monotonic decreasing | 0.0 dec. degrees | > 0.1 dec. degrees | Monotonic decreasing | 0.0 dec. degrees | > 0.1 dec. degrees |
Livestock density | Monotonic increasing | >1000 head/km2 | <10 head/km2 | Monotonic increasing | >1000 head/km2 | <10 head/km2 |