4: Health and Disease

Everybody gets sick and everyone eventually dies but, where you live is an important factor in how often and from what causes your health will suffer. Geography offers a powerful set of tools to investigate the spatial patterns of health and health care.

Medical Geography, also sometimes called Health Geography, is a vibrant subfield of the discipline. Great variations are evident in the patterns of both diseases and health care at many scales. Geographers use spatial analyses to figure out why people get sick. Geographers can also analyze patterns of health care, to measure the effectiveness of treatments. This chapter explores the patterns of health, disease, and treatment while presenting examples of how geographers use their epistemology, methodologies, and communication strategies in the fight to maintain the health and well-being of individuals and communities both in the United States and elsewhere.

The application of geographic techniques in the quest to address health crises is one of the earliest and most famous uses of spatial statistics to solve a pressing medical problem. In London in 1854, there was a severe outbreak of cholera, a gastrointestinal illness generally caused by drinking water contaminated by human feces. Back then, nobody quite understood that microscopic organisms, like bacteria, were capable of causing such violent illnesses. Instead, most medical experts believed that a kind of poisonous air, called miasma, was responsible for infectious diseases like cholera and the plague. The fear of miasma drove thousands, especially the wealthy, to seek healthy air in mountain or coastal resort towns. John Snow, a physician from London, worked in a neighborhood where there were many cases of cholera during the 1854 outbreak. Snow suspected that the miasmic air could not be the cause of cholera because other neighborhoods had similar air quality characteristics, but not the same rate of cholera. Instead, Snow guessed that the water supply was somehow contaminated, although he could not identify the “poison” in the water, even with a microscope. To test his theory, Snow first made a mental map of the locations where people had contracted cholera. He realized that cholera cases were spatially clustered around one public water well. Snow then hypothesized that if the handle to the water pump at the geographic center of the cholera outbreak was removed, then neighborhood residents would be forced to get water elsewhere, and the neighborhood incidence of cholera would subside. To test his hypothesis, Snow convinced local authorities to remove the well’s pump handle, and indeed the cholera epidemic lessened. Snow later made a physical point map indicating the location of the cholera patients’ residences and the poisoned well. Snow’s effort can be quickly replicated today using GIS and the results of simple statistical analyses of Snow’s data points to the remarkable accuracy of his initial hypothesis. More importantly, Snow’s map overturned centuries of bad science on disease while paving the way for the adoption of the germ theory of disease that is widely accepted today.

Though cholera still affects several million people per year, causing over 100,000 deaths worldwide, it is no longer the threat it once was, thanks in large part to advancements in basic water sanitation technology. Still, millions of people in the developing world have poor access to clean drinking water. As a result, water-born illnesses like cholera kill many thousands, especially children, through dehydration caused by diarrhea and vomiting.