Climate Change and Infectious Disease
Is a Warmer World a Sicker World?
Climate change is projected to influence the dynamics and distributions of many parasitic diseases of both humans and wildlife. Whether such changes will serve to increase or reduce disease depends on the differential thermal physiologies of parasites and their hosts. Available forecasts suggest that climate change will involve changes in both mean temperature and temperature variability, yet relatively little is known about how shifts in temperature affect parasite-host relationships.
With an emphasis on trematode parasites as a model system, we are combining experimental-based approaches both in the laboratory and in mesocosms with metabolic theory to develop a more predictive framework for how climate shifts will affect disease risk by different types of parasites (see Paull and Johnson 2011, Paull et al. 2012, Hoverman et al. 2013, Altizer et al. 2013). Concurrently, we are also using long-term data from small pond ecosystems in California to explore how changes in precipitation influence interactions between hosts and parasites. For instance, the recent megadrought in California, which is estimated to be among the most severe in the last 1,000 years, dramatically altered patterns of parasite richness, infection prevalence, and host pathology. This ‘natural experiment’ and the system’s subsequent response have provided a powerful opportunity to test hypotheses about the direct and indirect effects of drought on entire host-parasite assemblages.
Altman, K. A., Paull, S. H., Johnson, P. T. J., Golembieski, M. N., Stephens, J. P., LaFonte, B. E., and T. R. Raffel (2016). Host and parastie thermal acclimation responses depend on the stage of infection. Journal of Animal Ecology 85: 1014-2014.
Paull, S. H., Raffel, T. R., LaFonte, B. E. and P. T. J. Johnson (2015). How temperature shifts affect parasite production: Testing the roles of thermal stress and acclimation. Functional Ecology 29: 941–950.
Rohr, J. R., Blaustein, A. R., Paull, S. H., Johnson, P. T. J., Raffel, T., and S. Young (2013). Using physiology to understand climate-driven changes in disease and their implications for conservation. Conservation Physiology 1: doi:10.1093/conphys/cot022.
Hoverman, J. T., Paull, S. H., and P. T. J. Johnson (2013). Does climate change increase the risk of disease? Analyzing published literature to detect climate–disease interactions. In Pielke, R. Sr. (ed.), Climate Vulnerability: Understanding and Addressing Threats to Essential Resources, Vol. 4., Academic Press. DOI: http://dx.doi.org/10.1016/B978-0-12-384703-4.00406-8.
Paull, S. and P. T. J. Johnson (2013). Can we predict climate-driven changes to disease dynamics? Applications for theory and management in the face of uncertainty. Wildlife Conservation in a Changing Climate (J. F. Brodie, E. Post and D. Doak, eds.). University of Chicago Press.
Blaustein, A. R., Gervasi, S. S., Johnson, P. T. J., Hoverman, J. T., Belden, L. K., Bradley, P. W. and G. Y. Xie (2012). Ecophysiology meets conservation: understanding the role of disease in amphibian population declines. Philosophical Transactions of the Royal Society, Series B 367: 1688-1707.
Rohr, J. R., Johnson, P. T. J., Paull, S. H., Raffel, T. R., Dobson, A. P., Kilpatrick, A. M., Ruiz-Moreno, D., Pascual, M. and M. B. Thomas (2011). Frontiers in climate change-disease research. Trends in Ecology and Evolution 26: 270-277.
Paull, S. and P. T. J. Johnson (2011). High temperature enhances host pathology in a snail-trematode system: possible consequences of climate change for the emergence of disease. Freshwater Biology 56: 767-778.
In the Press
“Climate change altering infectious diseases”: A 2013 review published in Science illustrates how climate changes is already affecting infectious diseases in many parts of the globe and emphasizes the need to develop a more predictive framework to understand under what circumstances such changes are likely to pose problems for health and conservation. See news coverage by Science Daily and the National Science Foundation.