Are temperature suitability and socioeconomic factors reliable predictors of dengue transmission in Brazil?
Authors: Simon Lorena M. , Rangel Thiago F. 
Published: November 2020

Background

Dengue disease is an ongoing problem, especially in tropical countries. Like many other vector-borne diseases, the spread of dengue is driven by a myriad of climate and socioeconomic factors. Over recent years, mechanistic approaches have predicted areas of dengue risk according to the temperature effect on mosquitos’ lifespan and incubation period shaping their persistence and competence in transmission. Within developing countries such as Brazil, heterogeneities on socioeconomic factors are expected to create variable conditions for dengue transmission by its main vectors. However, both the relative role of socioeconomic aspects and its association with the temperature effect in determining the effective dengue prevalence are poorly understood.

Methodology/Principal findings

Here we gathered essential socioeconomic factors comprising demography, infrastructure, and urbanization over 5570 municipalities across Brazil and evaluated their relative effect on dengue prevalence jointly with a previously predicted temperature suitability for transmission. Using a simultaneous autoregressive approach (SAR), we showed that the variability in the prevalence of dengue cases across Brazil is highly explained by the combined effect of climate and socio-economic factors. Moreover, the temperature effect on transmission potential might be a better proxy at some dengue epidemy seasons but the socioeconomic factors are tightly linked with the recent increase of the dengue prevalence over Brazil.

Conclusions/Significance

In a large and heterogeneous country such as Brazil recognizing the drivers of transmission by mosquitoes is a fundamental issue to effectively predict and combat tropical neglected diseases as dengue. Ultimately, it indicates that not considering socioeconomic factors in disease transmission predictions might compromise efficient strategies of surveillance. Our study indicates that sanitation, urbanization, and GDP are regional indicators that should be considered along with temperature suitability for dengue transmission, setting a good starting point to effective vector-borne disease control.

AUTHOR SUMMARY

Dengue, a disease transmitted by mosquitoes, is a great problem in countries where the climate is predominantly hot and wet. Researchers know that temperature plays an important role in mosquitoes’ ability to transmits diseases. Usually, temperature alone is a good explanation for why dengue occurs in certain regions that have stable warm temperatures. Here we show that, in addition to the role of temperature on dengue spread, large urban areas with sanitation infrastructure and health assistance also prelude dengue cases prevalence. We highlight that dengue surveillance should consider socioeconomic regional differences. For instance, greater urban centers might be the focus of the dengue burden, where the presence of medical assistance and sanitation seems not to avoid the increase in disease cases. Conversely, less urbanized regions with suitable temperature for dengue transmission might require distinct actions for the disease combat.