Gauging the Impact of Flooded Rice Cultivation: Malaria in the California Great Central Valley, 1830--2010.

摘要

This dissertation examines the way in which mosquito-borne malaria has been assessed over time, and in light of historical and contemporary settlement and agricultural patterns, specific to California's Central Valley. The study includes observations in both northern and southern counties of the Central Valley, key informant interviews with epidemiologists, entomologists, local rice growers, and mosquito abatement personnel, and both archival and field research. In attempting to document evidence of malaria morbidity and mortality between 1830-2010, the study fused: historical landscape study (for nineteenth century North America), the ecological model (from biological sciences) and medical geography (itself an amalgam of botany, landscape and disease). Historic maps, and recent satellite data reveal the Central Valley's topography and landscape features. Statistics, available as extrapolated estimates from the 1830s, and more systematically gathered beginning in the 1870s, relate historical disease patterns in a way that may be used to interpret the contemporary landscape. A multi-county study area permitted sub-regional comparisons, between such variables as effect of water projects, irrigation agriculture, and vector control on mosquito ecology. One sees both the theoretical premise of the ecological model, and the empirical evidence inherent in an infectious disease. However, to understand how not only human populations within the Great Central Valley adapted to malaria, but how anopheline mosquitoes adapted to human settlement, the conceptual research model is framed within the human-environmental relationship. In this study, socio-environmental systems are shown adapting to disease; the perspective of human geography, specifically the "man-land tradition," integrates the work of medical, historical and cultural geographers. A second perspective, environmental history includes the work of historians who study disease within a human-environmental relationship. To some extent, a retrospective reality of malaria may still drive the current abatement methodologies, though any disease narrative ignores the past at its own peril. The California Central Valley manifests a complicated landscape, which is itself the result of history and the actions of those have settled it. In spite of incomplete and often erroneous health data, this study contributes to a greater understanding of the potential for re-emerging infectious disease in an agricultural region undergoing intense urbanization pressures.