Frontiers in climate change-disease research

Abstract

The notion that climate change will generally increase human and wildlife diseases has garnered considerable public attention, but remains controversial and seems inconsistent with the expectation that climate change will also cause parasite extinctions. In this review, we highlight the frontiers in climate change-infectious disease research by reviewing knowledge gaps that make this controversy difficult to resolve. We suggest that forecasts of climate-change impacts on disease can be improved by more interdisciplinary collaborations, better linking of data and models, addressing confounding variables and context dependencies, and applying metabolic theory to host-parasite systems with consideration of community-level interactions and functional traits. Finally, although we emphasize host-parasite interactions, we also highlight the applicability of these points to climate-change effects on species interactions in general.

Figure 1

Conceptual diagram displaying outstanding questions that should be addressed to improve understanding of climate change–disease interactions. The ‘Thinker’ is reproduced with permission from Wikimedia.org and the food-web image with permission from Joseph Luczkovich.

Figure I

Proposed framework for predicting host–parasite systems response to climate change. The 1, 0 and - symbols represent diseases that might be directly positively, neutrally, or negatively affected by climate change, respectively. Images reproduced with permission from Wikimedia Commons (http://commons.wikimedia.org/).

Figure 2

Effects of climate variability on Plasmodium growth in mosquitoes (a,b) and on frog declines (c) in genus Atelopus [sample species (d)] putatively associated with chytrid fungal infections. Growth rate and dissemination of Plasmodium chabaudi malaria in Anopheles stephensi mosquitoes at either a baseline mean temperature of (a) 16 °C or (b) 26 °C and under constant temperatures (dashed red lines) or temperatures with a diurnal temperature fluctuation of ±6 °C [diurnal temperature range (DTR) = 12 °C; solid blue lines]. The number of sporozoites per oocyst (circles, left) describes parasite growth kinetics up to the point of first sporozoite release, whereas dissemination (squares, right) describes the percentage of mosquitoes that were observed with mature sporozoites circulating in the hemocoel. Error bars = SE. (c) Results of a path analysis examining relationships among El Niño, the absolute value of monthly differences in temperature (AVMD), DTR and the rate at which species in the genus Atelopus were observed for the last time (Last Year Observed, LYO). Probability values and standardized coefficients, respectively, are provided next to each path. Image reproduced with permission from Richard A. Paselk.