Table 1.
Risk factors associated with the amplification and spread of Rift Valley fever in livestock populations as identified by the published literature review.
Fig 1.
Location of Rift Valley fever outbreaks in livestock reported in Kenya and Tanzania between 1998 and 2012.
Table 2.
Risk factor weights calculated using the analytical hierarchy process, regarding RVFV amplification and spread processes.
Fig 2.
Suitability maps for RVF amplification (a) and spread (b) are combined to produce a synthetic suitability map for RVF occurrence in livestock with nine classes corresponding to all possible combinations of amplification suitability (low/medium/high) and spread suitability (low/medium/high) (c) and a second synthetic RVF suitability map expressed as a continuous suitability index (d).
Fig 3.
Contribution of the different risk factor weights to model output variance.
Fig 4.
Assessment of the suitability index for RVF occurrence in livestock in Kenya and Tanzania.
a) ROC curve. b) Box-plot showing RVF occurrence suitability index values for cases (RVF outbreak locations) and controls (random ‘pseudoabsence’ locations). Box-plots show median values (solid horizontal line), 50th percentile values (box-plot outline), 90th percentile values (whiskers), and outlier values (open circles).
Fig 5.
Suitability maps for RVF occurrence and the locations of RVF outbreaks in livestock: a) Combination of amplification and spread suitability categories; (b) continuous suitability index.
Blue dots indicate the outbreak locations that were identified in the RVF at-risk areas. Yellow dots indicate outbreak locations not considered to be at-risk.