A groundbreaking study published in PLOS Neglected Tropical Diseases projects a significant increase in the risk of mosquito-borne diseases across Brazil by the year 2080, painting a vivid picture of the looming public health challenges driven by climate change and urbanization. Spearheaded by Katherine Heath of the Burnet Institute in Melbourne, Australia, alongside collaborators from the United Kingdom and Brazil, this rigorous computational modeling effort delivers some of the most detailed forecasts to date regarding the population dynamics of Aedes aegypti mosquitoes—the primary vectors of dengue, Zika, and chikungunya viruses—in response to evolving environmental and societal factors.
These mosquitoes thrive in urban environments, where they have ample access to human hosts and breeding sites, transmitting debilitating viruses through their bites. Prior epidemiological evidence has long highlighted correlations between warming temperatures, altered precipitation patterns, and rising incidences of mosquito-borne diseases globally. However, accurately projecting future transmission risks has remained a complex challenge, largely because of the intricate interplay between biological mosquito behaviors, climate variables, and anthropogenic forces such as urban sprawl.
To surmount this challenge, Heath and her team developed an innovative mathematical model grounded in delay-differential equations that explicitly incorporate lifecycle-dependent survival and reproductive rates of Ae. aegypti. This approach allows the model to simulate how temperature and rainfall impact mosquito development stages—from eggs through to adults—under different climatic scenarios. Furthermore, the model integrates human population growth and urban expansion data to refine predictions of mosquito-human interactions, which are critical to viral transmission dynamics.
The researchers employed Shared Socioeconomic Pathways (SSPs), a suite of standardized scenarios representing varying degrees of greenhouse gas emissions, climate mitigation policies, and urbanization trajectories, to explore how different futures might shape mosquito population densities through the latter half of the century. Under the lowest emissions scenario (corresponding to strong climate action), the nationwide density of Ae. aegypti mosquitoes is predicted to experience an 11% increase by 2080 compared to 2024. This modest uptick signals that while environmental changes still favor mosquito proliferation, mitigation efforts could substantially restrain their expansion.
In stark contrast, under the highest emissions scenario with continued urban growth and minimal climate interventions, Ae. aegypti densities are projected to rise by an alarming 30% across Brazil’s vast territory. Particularly concerning are designated hotspots in the South and Southeast regions, where mosquito densities could nearly double. These hotspots signify areas of heightened vulnerability due to a convergence of favorable climatic conditions and dense human populations, creating zones where the risk of arboviral outbreaks could surge exponentially.
Dengue fever, already a major cause of morbidity in Brazil, is expected to correspondingly intensify in scope and severity. The study meticulously illustrates that mosquito population growth in the Southeast will outpace human population growth, exacerbating transmission potential and challenging current public health infrastructures. This spatially and temporally granular forecasting underscores the need for targeted interventions, emphasizing the importance of localized vector control strategies alongside broad-scale emissions reductions.
Importantly, the model’s novelty lies in its dynamic capturing of both climatic and anthropogenic factors, offering a multifaceted view into the drivers of disease risk rather than simplistic temperature-based projections. By incorporating delay-differential equations, the researchers could simulate temporal lags in mosquito population responses to environmental stimuli, reflecting real-world biological processes more accurately. This technical sophistication enhances the reliability of the predictions, furnishing decision-makers with a robust scientific tool.
The implications of these findings stretch far beyond Brazil’s borders, as Ae. aegypti mosquitoes pose global threats in tropical and subtropical regions. As climate change reshapes temperature and rainfall patterns worldwide, similar modeling frameworks might become invaluable for anticipating evolving disease risks, guiding preventive measures, and resource allocation in vulnerable areas. The study’s evidence-driven emphasis on emissions reduction resonates with broader public health advocacy stressing climate action as a crucial strategy against vector-borne diseases.
Moreover, the research advocates for integrating public health planning with urban development policies. The interplay between urban expansion and mosquito ecology means that controlling breeding habitats—such as stagnant water in construction sites or domestic containers—could mitigate some projected risk increases. Therefore, intersectoral collaboration blending epidemiology, environmental science, urban planning, and community engagement is essential to preemptively lower disease burdens.
Heath’s team notes that Brazil already shoulders one of the highest global burdens of mosquito-borne viral diseases. The study’s projections portend a reinforcement of this heavy toll unless decisive climate policies and public health interventions are implemented. Strikingly, the researchers highlight that under a low-emissions future, projected mosquito density increases could be curtailed by as much as two-thirds compared to a high-emissions scenario, illustrating the stark differences that policy choices can make.
The study’s publication in an open-access format allows global access to these vital insights, encouraging further research and policy deliberations. Its computational modeling methodology exemplifies how modern scientific tools enable nuanced exploration of complex ecological and epidemiological phenomena, paving the way for more predictive, anticipatory public health science.
Future research building on this model might incorporate additional biological parameters, such as viral evolution or mosquito resistance to insecticides, to refine predictions further. However, the current study already establishes an essential foundation by quantitatively linking climate trajectories with tangible disease risk markers, underpinning the urgency of coordinated global action.
In summation, this ambitious and technically sophisticated study provides a sobering yet actionable forecast: climate change and urbanization will profoundly influence the density and distribution of Ae. aegypti mosquitoes in Brazil, with a direct bearing on the transmission of devastating arboviruses. Strong climate mitigation policies, combined with integrated vector management and urban planning, represent the most promising path to safeguarding public health in the decades ahead.
Subject of Research: Computational simulation/modeling of Aedes aegypti mosquito populations and arboviral disease transmission under climate change and urbanization scenarios in Brazil.
Article Title: Climate change, urbanisation and transmission potential: Aedes aegypti mosquito projections forecast future arboviral disease hotspots in Brazil.
News Publication Date: September 18, 2025
Web References:
10.1371/journal.pntd.0013415
References:
Heath K, Muniz Alves L, Bonsall MB (2025) Climate change, urbanisation and transmission potential: Aedes aegypti mosquito projections forecast future arboviral disease hotspots in Brazil. PLoS Negl Trop Dis 19(9): e0013415.
Image Credits: Raúl Escobar, Unsplash (CC0)
Keywords: Aedes aegypti, mosquito-borne diseases, dengue, climate change, urbanization, mathematical modeling, delay-differential equations, Brazil, arboviruses, Shared Socioeconomic Pathways, vector control, public health planning
