Climate and the Malarial Mosquito in Kenya:
Present Relationships and Future Implications
J. Scott Greene
Laurence S. Kalkstein
Paula J. Fornwalt
Center for Climatic Research
University of Delaware, Newark, DE 19716
Climate can play an influential role in the transmission of infectious diseases by acting
as a limiting factor on the vector's range and abundance. Thus, understanding how climate
affects vector dynamics will enhance our comprehension of disease transmission and ultimately
enable public health officials to improve the planning of disease prevention strategies.
In this study, a set of procedures was developed to assess the impact of climate on the malarial vectors Anopheles gambiae and Anopheles funestus, and to specify the climatic limiting factors. Specifically, water budgets were determined and used to estimate stream flows and water heights in northern Kenya, which were then used to estimate mosquito populations as well as the number of potentially infectious mosquitos. Results from this study indicate that climate does play an important role in the regulation of mosquito populations in northern Kenya. Based on computed water heights, population fluctuations can be estimated with a measured degree of confidence. Mosquito populations exhibit a seasonality linked to changes in precipitation and energy characteristics of the region. Finally, climate change scenarios were used to project how climate change might affect future mosquito populations. Results show that increases in temperature and precipitation throughout the region will alter current mosquito distributions. Although uncertainties exist about future climate and regional patterns of change, these scenarios provide useful insights about potential vulnerabilities and health impacts.