GIS on the Front Lines in Fighting Disease

December 19, 2007 By: Finnian O'Cionnaith

Epidemiology — tracking the spread of disease, in order to better control and prevent it — benefits greatly from the use of mapping tools. Public health departments worldwide are employing GIS, demographic information, and remote sensing data in their battles with bird flu, malaria, and cancer.

On March 4, 1918, at Fort Riley in Kansas, Company Cook Albert Gitchell reported to the infirmary with flu-like symptoms. Two days later, more than five hundred men at the camp complained of illness. Within five months, outbreaks were reported as far away as France and Sierra Leone. A year after Gitchell became sick, up to twenty-five million people had died of H1N1, more commonly known as Spanish influenza.

We are currently on the verge of a new pandemic with H1N1's progenitor H5N1, also known as avian influenza or bird flu. A pandemic is defined as an outbreak of infectious disease that strikes a very wide area. It can last for years and may affect the entire planet's population. In addition to the deaths that organizations such as the United Nations and World Health Organization (WHO) have predicted will occur because of H5N1, the pandemic is expected to have a massive economic and social impact.

GIS is a tool which can be used to fight this upcoming pandemic, as well as many diseases that trouble not only the developing world, but Ireland as well. By mapping the spread of an epidemic and identifying high-risk population centers before the epidemic reaches them, GIS can decrease the loss of life and help in the eradication of the pathogen by tracking local mutations. The H5N1 avian flu, malaria, and cancer are just three of the diseases being planned for and fought with GIS today.

GIS and Epidemiology

The first real combination of maps and medicine occurred in 1854, when an outbreak of cholera hit London's Soho district. Dr. John Snow plotted the location of every case of the disease within Soho, and was able to show that they were reasonably localized. Since cholera is a water-borne disease, it stood to reason that a water source within the outbreak area was responsible. Snow's groundbreaking mapping method revealed that the source was a public water pump used by the locals for drinking and washing water, which had been contaminated with water from the Thames. That determination was the birth of epidemiology.

John Snow's map of the 1854 Soho cholera epidemic.

GIS has created new opportunities for public health administrators to enhance the preparation for, analysis of, and monitoring of epidemics. It can be used as a convergence point for multisector data, compiling epidemiological surveillance information, population data, environmental conditions, and health resources in a common platform. It has the ability to process not only map data, but also remotely sensed data, enabling information such as temperature, rainfall, soil types, and land use to be easily integrated, and spatial correlations between potential risk factors and the occurrence of the disease to be determined.