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).