PARENT SESSION
Thursday, August 10, 8:00-11:30 am
Symposium 17 - Biodiversity, ecosystem processes, and human health
Ballroom B, Ballroom Level, Cook Convention Center
Organized by: AR Townsend (alan.townsend@colorado.edu) and O Sala
This symposium will present an overview of how human-driven changes in biodiversity and ecosystem processes can affect human health, and how ecologists can help understand and potentially mitigate the health effects of global environmental change.
Biological amplification, climate trends, and malaria resurgence in African highlands.
Pascual, Mercedes *,1, Chaves, Luis 1, Ahumada, Jorge 2, Rodo, Xavier3, Bouma, Menno 4, Abeku, Tarekegn4, 1 University of Michigan, Ann Arbor, MI2 Conservation International, Washington, DC3 University of Barcelona, Barcelona, Spain4 London School of Hygiene and Tropical Medicine, London, England
ABSTRACT- The incidence of malaria in East African highlands has increased since the end of the 1970's. The role of climate change in the exacerbation of the disease has been controversial because of the multiplicity of potential drivers, including drug resistance, insecticide resistance, and population increases. Moreover, the specific influence of warming has been highly debated following a previous study reporting no evidence to support a trend in temperature. We revisit this finding with the same temperature data now updated to the present from 1950 to 2002 for four high-altitude sites in East Africa where malaria has become a serious public health problem. With both nonparametric and parametric statistical analyses, we find evidence for a significant warming trend at all sites. To assess the biological significance of this trend, we drive a dynamical model for the population dynamics of the mosquito vector with the temperature time series and the corresponding de-trended versions. This approach suggests that the observed temperature changes would be significantly amplified by the mosquito population dynamics with a difference in the biological response at least one order of magnitude larger than that in the environmental variable. A fifth site is used to illustrate more subtle patterns of change in temperature and to present evidence for the importance of these patterns in driving the observed increase in cases, relative to other factors including DDT and population size. Our results emphasize the importance of thresholds and biological amplification in the response of vector-transmitted diseases to climate change.
Key words: Infectious diseases and climate change, biological amplification and thresholds, dynamical model