Mean monthly rainfall rate (mm) from IMERG gridded satellite data in New Caledonia, Fiji, Tahiti, Reunion Island, Mayotte, Futuna, Vanuatu, and Puerto Rico. Rainfall was averaged over the period of leptospirosis data for each island (see Table 1).

Baseline map made with Natural Earth. Free vector and raster map data @ naturalearthdata.com and contains information from OpenStreetMap and OpenStreetMap Foundation, which is made available under the Open Database License (https://opendatacommons.org/licenses/odbl/). No changes where made to the original map. Guadeloupe, Reunion island and Mayotte administrative divisions were downloaded from https://data.humdata.org. New-Caledonia administrative divisions were provided by Kontur (https://www.data.gouv.fr). Tahiti boundaries were provided by the Section Cadastre-Topographie de la Polynésie française (https://www.data.gouv.fr). Futuna boundaries were provided by SPC—SDD Statistics for Development (https://pacificdata.org). Vanuatu administrative boundaries were provided by Secretarial of the Pacific Community (SPC), Statistics for Development Division, Fiji boundaries were provided by Fiji Islands Bureau of Statistics, Pacific Catastrophe Risk Assessment and Financing Initiative (PCRAFI) and Puerto Rico boundaries were provided by GADM project (https://data.humdata.org).</p

Third dimension of the principal component analysis plotted against dimension 1 and 2 for Tahiti and Futuna.

Third dimension of the principal component analysis plotted against dimension 1 and 2 for Tahiti and Futuna.</p

Principal Component Analysis (PCA) for each island and the observed anomalies of log incidence.

The correlation of variables (arrows) and individuals are projected in the two first dimensions of the PCA. The percentage of variability explained by the two first dimensions of the PCA is given within brackets. Each individual of the PCA represents a month of the leptospirosis time-series. The sign (+/-) and the intensity (size) of the anomalies of log incidence were represented.</p

Effect of the explanatory variable in the SVR seasonal model.

The importance score (a) represents the increase in MAE caused by repeated permutations of the variable in the dataset. The partial dependence curves (b) estimate the marginal effect of each variable by computing the average (blue line) (± standard error, blue ribbon) of Individuals Conditional Expectancy (ICE) curves (see methods).</p

Leave-island-out MAE scores for the tested global seasonal models.

Leptospirosis normalized seasonal profile was estimated based on the normalized seasonal profile of temperature (S(T)) and precipitation (S(P)) with a lag ranging from 0 to 2 months. We performed normalization by removing the mean of the variables in each island. The black dotted boxes frame the best model selected for modelling the leptospirosis seasonal dynamics. (TIF)</p

Leave-year-out Δ<i>MAE</i> scores of the per island inter-annual models.

Models estimate the anomalies of log incidence based on precipitation and temperature anomalies (respectively A(P) and A(T)) with a lag ranging from 0 to 2 months. ΔMAE compares the accuracy of the predicted incidence to the seasonal profile. The black dotted boxes frame the best models selected for modelling the leptospirosis anomalies in each island. (TIF)</p

Observed and predicted normalized seasonal profile of leptospirosis.

We adjusted a global SVR model encompassing Reunion Island, Guadeloupe, Tahiti, Fiji, New Caledonia, and Mayotte with normalized seasonal precipitation at lag 0 and 2 and temperature at lag 0 to 1 months as explanatory variables. The predicted seasonal profile (blue line) was obtained using a) cross-validation on the island used to build the model and b) prediction of the global model for the island not included in the model. The observed seasonal profile (black line with dots) was obtained by computing the median incidence each month.</p

Leptospirosis, precipitation and temperature seasonal profiles of the studied Islands.

The seasonal profile for Reunion Island (a), Guadeloupe (b), Tahiti (c), Fiji (d), New Caledonia (e), Mayotte (f) and Futuna (g) are defined by the mean temperature (°C—red line) and the mean precipitation rate (mm/hr—grey bar) of each month (left panel). Leptospirosis profile is given in incidence per 100,000 inhabitants and was defined as the median value of incidence of each month (blue line). (TIF)</p

Characteristics of New Caledonia, Fiji, Tahiti, Reunion Island, Mayotte, Futuna, Guadeloupe, Vanuatu and Puerto Rico.

Characteristics of New Caledonia, Fiji, Tahiti, Reunion Island, Mayotte, Futuna, Guadeloupe, Vanuatu and Puerto Rico.</p

Effect of the explanatory variable in the SVR inter-annual models adjusted on each island.

The importance score (a) represents the increase in MAE caused by repeated permutations of the variable in the dataset. The partial dependence curves (b) estimate the marginal effect of each variable by computing the average (blue line) (± standard error, blue ribbon) of ICEs curves (see methods).</p