Seasonal baseline (solid line) and upper limit of the 95% confidence interval (dashed line).

<p>The observed number of leptospirosis cases in each month is shown for 2007–2012. Blue circles indicate months that had been forecasted to be below the epidemic threshold and red crosses indicate months where the forecast predicted an epidemic. When the red crosses are above the 95% confidence interval, this indicates that the forecast had correctly predicted an epidemic intensity in that month.</p

Observed (grey) and predicted (red) cases of leptospirosis occurring in each month in New Caledonia, 2000–2012.

<p>Observed (grey) and predicted (red) cases of leptospirosis occurring in each month in New Caledonia, 2000–2012.</p

El Niño Southern Oscillation and Leptospirosis Outbreaks in New Caledonia

<div><p>Leptospirosis is an important cause of seasonal outbreaks in New Caledonia and the tropics. Using time series derived from high-quality laboratory-based surveillance from 2000–2012, we evaluated whether climatic factors, including El Niño Southern Oscillation (ENSO) and meteorological conditions allow for the prediction of leptospirosis outbreaks in New Caledonia. We found that La Niña periods are associated with high rainfall, and both of these factors were in turn, temporally associated with outbreaks of leptospirosis. The sea surface temperature in El Niño Box 4 allowed forecasting of leptospirosis outbreaks four months into the future, a time lag allowing public health authorities to increase preparedness. To our knowledge, our observations in New Caledonia are the first demonstration that ENSO has a strong association with leptospirosis. This association should be tested in other regions in the South Pacific, Asia or Latin America where ENSO may drive climate variability and the risk for leptospirosis outbreaks.</p></div

Human T-cell lymphotropic virus type 1 serologic confirmation by Western blot.

<p>HTLV-1 seroreactivity patterns obtained by Western blot with recombinant GD21 (common to HTLV-1 and HTLV-2) and two synthetic peptides specific for HTLV-1 (MTA-1) and HTLV-2 (K55). Lane 1, HTLV-1 positive control; lane 2, HTLV-2 positive control; lane 3, HTLV-1/2 negative control; lanes 4–6, plasma samples from the HTLV-1 positive women from New Caledonia (NCP91, NCP173 and NCP201) displaying a strong reactivity to GD21 and to p19, p24, p26, p28, p32, p36 plus rgp46-I (MTA-1).</p

Map of the western Pacific region.

<p>The Australo-Melanesia region comprises the islands group extending from Papua New Guinea to New Caledonia including Solomon Islands and Vanuatu archipelago plus Australia, where HTLV-1 epidemiological and clinical situation has been investigated.</p

Phylogenetic tree generated with neighbor-joining (NJ) method on a 2,346-bp fragment of the HTLV-1 <i>gag-tax</i> concatenated genes for 29 HTLV-1 available sequences including the 2 sequences generated in this work (NCP201 and EM5).

<p>HTLV-1 strains were aligned with DAMBE software (version 4.2.13). The final alignment was submitted to the Model test program (version 3.6) to select, according to the Akaike Information Criterion (AIC), the best model to apply to phylogenetic analyses. The selected model was the GTR. The numbers at some nodes of the tree (bootstrap values) were calculated for 1,000 replicates and indicate frequencies of occurrence for 100 trees (bootstrap ≥50%). The branch lengths are drawn to scale with bar indicating 0.01-nucleotide replacement per site. The ATK-1 strain was used as outgroup. The NCP201 and EM5 strains belong to the Australo-Melanesian HTLV-1c subtype and clustered with the strains previously characterized in Vanuatu (ESW44) the Solomon Islands (Mel5). Strains from Central Australia constitute a second clade (Genbank accession nos. KX905202 and KX905203).</p

Phylogenetic tree generated with Neighbor-joining (NJ) method on a 522-bp fragment of the HTLV-1 gp-21 <i>env</i> gene for 25 HTLV-1 available sequences including the 2 sequences generated in this work (NCP201 and EM5).

<p>HTLV-1 strains were aligned with DAMBE software (version 4.2.13). The final alignment was submitted to the Model test program (version 3.6) to select, according to the Akaike Information Criterion (AIC), the best model to apply to phylogenetic analyses. The selected model was the Tamura Nei. Bootstrap values were calculated for 1,000 replicates and indicate frequencies of occurrence for 100 trees (bootstrap ≥50%). The branch lengths are drawn to scale with bar indicating 0.01-nucleotide replacement per site. The ATK-1 strain was used as outgroup. The NCP201 and EM5 strains belong to the “Solomon/Vanuatu/New Caledonian” sub-clade, while the two other “Australian” and “Papua New Guinean” clades exist within HTLV-1c subtype. (Genbank accession nos. KX905202 and KX905203).</p

Human T-cell lymphotropic virus type 1 serologic screening tests.

<p>Human T-cell lymphotropic virus type 1 serologic screening tests.</p

Spatial heterogeneity of dengue annual incidence rates in New Caledonia.

<p>Map of annual incidence rates per commune averaged over epidemic years of the 1995–2012 period (years 1995, 1996, 1998, 2003, 2004, 2008, 2009).</p

Results of the best multivariable model of the spatial structure of dengue incidence rates.

<p><b>A:</b> Predicted mean (across epidemic years) annual incidence rates as a function of the two best explanatory variables (mean temperature and mean number of people per premise). The axes represent the value of the two best explanatory variables. Predicted average annual incidence rates are represented by the colour (blue for low incidence rates to orange for high incidence rates) and by the contour lines giving incidence rates in number of cases per 10,000 people per year. Each commune that has been used to build the model is placed on the graph according to the observed value of the two explanatory variables in the commune. Its position on the graph hence provides the average (across epidemic years) annual incidence rate in the commune as predicted by the model. For each commune, the coloured dot represents the difference between the predicted and the observed incidence rate (model error). <b>B:</b> Scatter plot of the predicted and observed average (across epidemic years) annual incidence rates for each of the 28 communes. The RMSE of this model is 45 cases per 10,000 per year.</p