Stanford geographers examining how and why humans alter their environment are gaining new insights into the relationship between land, humans and disease-carrying parasites such as ticks and mosquitoes.
In the study, researchers combined images from orbiting satellites with data obtained from door-to-door interviews. The initial goal was to gain a deeper understanding about complex conditions that give rise to a broad range of land-use challenges, but geographers took the research a step further and uncovered additional information about the spread of parasitic diseases in Belgium and Thailand. According to the Stanford release:
In Belgium, Lyme disease is common among the urban middle class but rare among the rural poor. The ticks that carry Lyme disease run free in parks and forests where people jog or bike but not in farmlands. However, Belgian farmers are more likely to contract a type of Hantavirus that lies in wait in soil dust.
In northern Thailand, when loggers chop down trees, the forest opens and the puddles that breed malaria-causing mosquitoes evaporate. When the deforested areas are converted into fruit orchards, the malarial mosquitoes are replaced by a different species that carries dengue fever - the leading cause of hospitalization and death among Thai children.
Using satellite land-cover maps, epidemiological data and surveys of farming households, [geographers] concluded that the shift from malaria to dengue fever was in large part caused by the presence of fruit workers in what had been a remote forest.
Researchers say diseases are one example of the complexities hidden within the static pixels of satellite images.
Photo by NASA Goddard Space Flight Center