Evidences of coupling between El Niño-Southern Oscillation and Dengue
incidence in Colombia
Abstract
The El Niño-Southern Oscillation (ENSO) phenomenon is the main mechanism
forcing climate variability in tropical South America in several
timescales, impacting the life cycles of disease vectors and host/vector
relationships. The dengue is a vector-borne disease with great
socioeconomic impact in Colombia, being the arbovirus with the highest
mortality. In this analysis, we related the records of Dengue cases
registered in Colombia in the period 2007-2017 and the series of sea
surface temperature anomalies in the Niño 3.4 region. Furthermore, we
studied the effect of the ENSO on precipitation, relative humidity,
maximum and minimum air temperature, and wind velocity in Colombia to
understand the impact of the ENSO in the dengue incidence. The effect of
the ENSO on climatic variables spatially varies. During the warm (cold)
phase, i.e., El Niño (La Niña), the maximum and minimum air temperature
increase (decrease) throughout the country, but in the Amazonian region,
it is less likely to occur. During El Niño the mean rainfall decreases,
except in the Orinoquía region where it can increase. In the Pacific and
Caribbean regions, rainfall is more likely to decrease in this phase of
the ENSO, while surface radiation increases in the Andean region. Wind
speed increases in the Andean, Caribbean and Pacific regions, and
decreases in the Orinoquía and Amazonian regions. El Niño phase
intensifies the incidence rate of Dengue in the Andean, Caribbean, and
Pacific regions (correlation between 0.3 and 0.8 with 95% of confidence
for lags between 1 and 14 months approximately) and La Niña in the
Amazonian and Orinoquía regions (correlation between 0.2 and 0.5 with
95% of confidence for lags between 10 and 20 months approximately). The
above should be explained by the decreasing in rainfall and increasing
on temperature and wind velocity (less relative humidity) in the Andean,
Caribbean and Pacific regions, and the increase in radiation in the
Andean region during El Niño. On the other hand, during La Niña,
rainfall decreases in the Orinoquía region and decreases on the
temperature are unlike in the Amazonian region.