Intersecting vulnerabilities: Climatic and demographic contributions to future population exposure to Aedes-borne viruses in the United States

Abstract

Understanding how climate change and demographic factors may shape future population exposure to viruses such as Zika, dengue, or chikungunya, transmitted by Aedes mosquitoes is essential to improving public health preparedness. In this study, we combine projections of cumulative monthly Aedes-borne virus transmission risk with spatially explicit population projections for vulnerable demographic groups (age and economic factors) to explore future county-level population exposure across the conterminous United States. We employ a scenario matrix -combinations of climate and socioeconomic scenarios (Representative Concentration Pathways and Shared Socioeconomic Pathways) -to assess the full range of uncertainty in emissions, socioeconomic development, and demographic change. Human exposure is projected to increase under most scenarios, up to +177% at the national scale in 2080 relative to 2010. Projected exposure changes are predominantly driven by population changes in vulnerable demographic groups, although climate change is also important, particularly in the western region where future exposure may decrease by >30% under the strongest climate change mitigation scenario. The results emphasize the crucial role that socioeconomic and demographic change play in shaping future population vulnerability and exposure to Aedes-borne virus transmission risk in the United States, and underscore the importance of including socioeconomic scenarios in projections of climate-related vector-borne disease impacts.

Trade-off between climatic and human population impacts on Aedes aegypti life history shapes its geographic distribution

“…In addition to climate factors, human population contributions to the expansion of Aedes aegypti and future population exposure to Aedes-borne virus might also be of large importance (Rohat et al, 2020). Our model revealed that a future human population change significantly influences the climate-based predictions (Fig.…”

“…Our model is an extension of a previous model (Liu-Helmerssne et al, 2019a) by incorporating predicted population patterns into the mosquito's life history traits. This incorporation makes our model advantageous over previous models where predicted population patterns were merely used to estimate future population vulnerability and nearly independent of the mosquito's life history (Monaghan et al, 2018;Kraemer et al, 2019;Messina et al, 2019;Rohat et al, 2020), in terms of minimizing skewed estimates of climatic impacts across different SSPs.…”

“…Conversely, the reduced infestation potential in an environmentally less friendly region can be compensated by high blood-mediated fecundity rate (e.g., the east). The crucial role of population changes has also been strongly emphasized by a couple of previous studies using projected population patterns and climate changes to assess the future population exposure to Aedes-borne virus from non-mechanistic perspectives (Monaghan et al, 2018;Kraemer et al, 2019;Messina et al, 2019;Rohat et al, 2020). Taken together, the future distribution of Aedes aegytpi will be substantially impacted by the interplay between climatic and human factors.…”

“…This is mainly because Aedes aegypti is an urban vector where the habitation sites are rarely found more than a hundred meters away from human houses and they feed almost entirely on human blood, making human beings perfect hosts (Ponlawat and Harrington, 2005;Reiter, 2007). However, very few studies have used the projected human population growth scenarios in a mechanistic modelling framework in order to estimate the future populations exposure to Aedes aegypti, an important research gap since a growing number of primarily statistical studies have suggested the crucial role of socioeconomic changes in the predictions of the development of climate-related vector-borne diseases (e.g., Kraemer et al, 2019;Messina et al, 2019;Monaghan et al, 2018;Rohat et al, 2020, Liu-Helmersson et al, 2019b.…”

Disentangling the contribution of socioeconomic pathways to future climate-related risks : The case of heat stress

“…For instance, in the field of climate-sensitive vector borne diseases studies, the overwhelming majority of risk assessments are still superimposing RCPs-based climate projections on the current state of the society (e.g. Ryan et al, 2019)although a few recent exceptions must be pointed out (Monaghan et al, 2018;Messina et al, 2019;Rohat et al, 2019d). This is particularly problematic because socioeconomic development -and in particular migration, urbanization, economic development, and population growth -are thought to be key drivers of the spread of vector-borne diseases.…”