Global Change and Emerging Infectious Diseases

Abstract

Our world is undergoing rapid planetary changes driven by human activities, often mediated by economic incentives and resource management, affecting all life on Earth. Concurrently, many infectious diseases have recently emerged or spread into new populations. Mounting evidence suggests that global change-including climate change, land-use change, urbanization, and global movement of individuals, species, and goods-may be accelerating disease emergence by reshaping ecological systems in concert with socioeconomic factors. Here, we review insights, approaches, and mechanisms by which global change drives disease emergence from a disease ecology perspective. We aim to spur more interdisciplinary collaboration with economists and identification of more effective and sustainable interventions to prevent disease emergence. While almost all infectious diseases change in response to global change, the mechanisms and directions of these effects are system specific, requiring new, integrated approaches to disease control that recognize linkages between environmental and economic sustainability and human and planetary health.

Keywords: climate change; emerging infectious diseases; global change; land-use change; spillover; urbanization.

Figure 1

Impacts of global change on emerging infectious diseases can be nonlinear, complex, and/or exhibit threshold effects. (a) Global changes that affect temperature, such as climate change, land-use change, and urbanization, may have nonlinear effects on disease transmission. For many mosquito-borne diseases, accumulating evidence suggests a hump-shaped relationship between temperature and disease transmission. Thus, a given temperature increase can have different effects on disease transmission in different contexts depending on the baseline, causing a small increase (yellow arrow), a large increase (orange arrow), no change (red arrow), or a decrease (dark red arrow) in disease transmission. (b) The effects of rainfall on mosquito-borne disease transmission are more complex, since the rainfall-transmission relationship (linear or nonlinear) depends on vector ecology and factors related to human behavior and the built environment, or largely remain unresolved (dashed lines). (c) Global changes that alter the landscape and habitat, such as land-use change and urbanization, may promote or suppress transmission of emerging diseases depending on the disease and its ecology. Here are some examples of how different vector-borne or zoonotic emerging diseases are expected to vary across a land-use gradient. Ae. stands for Aedes, and arboviruses are Aedes-borne viruses (e.g., dengue, Zika, and yellow fever). Figure adapted with permission from Shocket et al. (2021).