Supplementary appendix This appendix formed part of the original submission and has been peer reviewed. We post it as supplied by the authors. Supplement to: Lowe R, Stewart-Ibarra AM, Petrova D, et al. Climate services for health: predicting the evolution of the 2016 dengue season in Machala, Ecuador. Lancet Planet Health 2017; 1: e142 51.
Climate services for health: predicting the evolution of the 2016 dengue season in Machala, Ecuador Appendix C A B Figure A1: Land use in Machala, Ecuador Machala is a midsize port city (latitude: 3.3 S, longitude: 79.9 W, elevation: 6 metres above sea level) located on the Pacific Ocean in El Oro province in southern Ecuador. The map indicates the following: (A) land use around Machala, (B) a map of Ecuador showing the location of El Oro province in red, (C) a map of Latin America showing the location of Ecuador. 1
Dengue cases 0 200 400 600 800 1000 1400 Chikungunya Dengue J F M A M J J A S O N D Figure A2: Reported dengue cases and proportion estimated to be chikungunya in 2015 Proportion of monthly reported dengue cases (from Ministry of Health passive surveillance system) in 2015 estimated to be chikungunya cases (blue portion of bar), based on results from an active surveillance study. 1 Table A1: Corrected dengue cases in 2015 ly dengue cases reported by the Ministry of Health passive surveillance system, proportion of confirmed chikungunya cases from an active surveillance study 1 and corrected dengue cases in 2015. Reported dengue cases Proportion of confirmed chikungunya cases Corrected dengue cases Jan 16 0% 16 Feb 14 0% 14 Mar 29 14.3% 25 Apr 80 10.5% 72 May 332 43.2% 189 Jun 1392 60% 557 Jul 717 65% 251 Aug 162 70% 49 Sep 76 40% 46 Oct 36 0% 36 Nov 15 0% 15 Dec 8 0% 8 2
Dengue incidence 0 20 40 60 80 a J M M J S N Precipitation (mm/day) 0 1 2 3 4 5 6 7 b Precipitation Mean temperature Min/max temperature J M M J S N 22 24 26 28 30 32 Temperature ( C) Figure A3: Annual cycle of dengue and climate Mean annual cycle of (a) dengue incidence (per 100,000 population) and (b) average precipitation (mm/day; bars), mean temperature ( C; solid curve), maximum and minimum temperature (dashed curves) for Machala, Ecuador, for the period 2002-2015. 3
Precipitation (mm/day) 0 2 4 6 8 10 a Minimum temperature ( C) 20 21 22 23 24 25 b J F M A M J J A S O J F M A M J J A S O Figure A4: Ensemble seasonal climate forecasts in 2016 Ensemble forecast (24 ensemble members) initiated on the 1 January 2016 showing monthly averages of (a) precipitation (mm/day) and (b) minimum temperature ( C), for the 10 months following the forecast start date (January-October 2016). Observations from the weather station in Machala are also shown (dashed black curve). 4
Figure A5: Selected grid point for bias correction Topography in the Ecuador area as seen by the Climate Forecast System version 2 (CFSv2) model with 1 degree resolution (111 km at the Equator). Points marked as sea by the model land-sea mask are shaded in blue. The weather station in Machala is indicated with a red dot. The grid point chosen as being representative of the climate in Machala is marked with a black cross. Min. Temperature ( C) 26 24 22 20 18 16 14 a Observation Forecast Min. Temperature ( C) 12 26 24 22 20 1986 19871988 b 1989 19901991 1992 19931994 1995 19961997 1998 19992000 2001 20022003 Year 2004 20052006 2007 20082009 Observation 2010 20112012 2013 20142015 Forecast 1986 19871988 1989 19901991 1992 19931994 1995 19961997 1998 19992000 2001 20022003 Year 2004 20052006 2007 20082009 2010 20112012 2013 20142015 Figure A6: Bias in temperature forecasts for nearest grid point and most representative grid point Raw monthly forecasts from the Climate Forecast System version 2 (CFSv2) model for Machala, Ecuador, from January to October 1986-2015 for (a) the grid point nearest to Machala weather station and (b) the grid point immediately to the west. The shaded areas represent the 95% confidence intervals for the ensemble forecast (24 members). Observations from the weather station located in Machala for 1986-2015 (black curve) are included. 5
log(dengue incidence) 0 2 4 6 8 10 2011 2012 2013 2014 2015 J F M A M J J A S O N D Figure A7: Dengue incidence 2011-2015 Log dengue incidence (per 100,000 population) in Machala, Ecuador for the years 2011 (solid red curve), 2012 (solid blue curve), 2013 (dashed green curve), 2014 (dashed purple curve) and 2015 (dotted orange curve) in Machala, Ecuador. This data was used to calculate the five-year mean dengue incidence and 95% confidence interval of the mean dengue incidence, used as benchmark thresholds in the 2016 dengue forecast. 6
log(dengue incidence) 0 2 4 6 8 10 Observed Mean (2011 2015) Upper 95% CI (2011 2015) Predicted median 2016 95% prediction interval J F M A M J J A S O N log(dengue incidence) 0 2 4 6 8 10 Observed Mean (2011 2015) Upper 95% CI (2011 2015) Predicted median 2016 95% prediction interval Figure A8: Probabilistic dengue forecast 2016 before and after correcting the reported dengue cases Posterior predicted median (dashed purple curve) and 95% prediction (credible) interval (purple shaded area) for log dengue incidence (per 100,000 population) in Machala, Ecuador, January November 2016. The five-year mean dengue incidence (blue curve) and upper 95% confidence interval (red curve), for the period 2011-2015, is shown. Observed dengue incidence rates are also included (dashed black curve). The predictive model was simulated, and five-year mean and upper confidence interval curves calculated, before correcting the reported dengue cases (upper panel) and after correcting the reported dengue cases (lower panel; see figure 4 in Article), i.e. by removing the proportion of cases thought to be chikungunya based on an active surveillance study 1. References J F M A M J J A S O N 1 Stewart-Ibarra AM, Kenneson A, King CA, et al. The high burden of dengue and chikungunya in southern coastal Ecuador: Epidemiology, clinical presentation, and phylogenetics from a prospective study in Machala in 2014 and 2015. biorxiv 2017; 102004. 7