Table 1.
Results of general additive modeling (GAM) explaining the number of outbreaks of infectious diseases, zoonotic or vector-borne, per country and per year, with forest cover or oil palm areas, human population size and the matrix of longitude/latitude of country centroids as independent variables, using a negative binomial link and controlling for spatial and temporal effects, with approximate significance of smooth terms (edf, estimated residual degrees of freedom; df, degree of freedom) (see Methods for the models, data from GIDEON, FAOSTAT and World Bank) (see Figure 3).
| Response variable | Explanatory variables | edf | Chi2 (df) | P-value | Deviance (in%), R2 adjusted, n |
|---|---|---|---|---|---|
| 1. Outbreaks of zoonotic diseases | (Forest cover, year) | 19.7 | 106 (29) | <0.0001 | |
| (Population size, year) | 19.9 | 1,250 (28) | <0.0001 | ||
| (Longitude, latitude) | 24.1 | 645 (29) | <0.0001 | 53.4, 0.65, 5311 | |
| 2 Outbreaks of vector-borne diseases | (Forest cover, year) | 13.4 | 52.5 (29) | <0.0001 | |
| (population size, year) | 17.0 | 619.8 (28) | <0.0001 | ||
| (Longitude, latitude) | 21.2 | 348.1 (29) | <0.0001 | 40.5, 0.49, 4784 | |
| 3. Outbreaks of zoonotic diseases | (Oil palm area, year) | 0.001 | 0.0 (29) | 0.54 | |
| (Population size, year) | 15.1 | 488 (28) | <0.0001 | ||
| (Longitude, latitude) | 11.7 | 161 (29) | <0.0001 | 55.1, 0.65, 1126 | |
| 4. Outbreaks of vector-borne diseases | (Oil palm area, year) | 1.74 | 6.79 (29) | 0.0029 | |
| (Population size, year) | 11.05 | 127.34 (28) | <0.0001 | ||
| (Longitude, latitude) | 11.25 | 81.74 (29) | <0.0001 | 49.3; 0.54, 1072 |