John Snow's map of cholera saved lives. Searching for a possible cause of a cholera epidemic in London in 1854, Snow's attempt to superimpose a map of cholera deaths with a map of public water supplies geographically linked the Broad Street pump as a potential source of cholera in the urban population. His hypothesis resulted in the closure of the pump to the public, and a rapid decrease in instances of cholera followed. John Snow's use of geography led to a new understanding of where cholera infection originated from, contact with contaminated water. Maps can be powerful tools for analyzing data and communicating public health information to decision makers.
Snow's discovery was an indication of the power of mapping the spread of diseases. Since then, technology has allowed us to map more data and compute more sophisticated spatial analysis. The most recent advancement of this technology has been geographic information systems (GIS). GIS is a system used to compile, store, analyze and present geographic information. GIS applications are varied and include environmental resource monitoring, infrastructure development planning, and agriculture among others. These are all examples of fields with problems that can be solved by spatial analysis. Public health, and by extension global health, stand to benefit from the power of GIS and in some cases already are.
GIS provides global health practitioners with another mean to practice informatics as well as a tool for making geographically related decisions. It provides those who use is a visualization of their data, which allows for easier interpretation. Imagine pouring over data tables of instances of deaths in 2012 due to lung disease presented by county. It could take quite a while to determine where high-risk counties exist. Now imagine a map of all US counties, colored according to their death rates attributed to lung disease. The light colored counties are those with fewer lung disease deaths per population and as the rate of instance increases, the color darkens. You can literally see areas of the country where people are at higher risk. This geographic correlation does not prove that simply living in Utah, for example, puts you at an elevated risk, but it does give you a causal reason to further examine why a geographic region experiences higher or lower rates. In Snow's case, a geographical relation was reason enough to close a particular water supply, and help stop the spread of cholera. Now lets imagine you want to find locations for 3 pre-natal care facilities in an urban setting. How great would it be to know what neighborhoods had high populations of women in reproductive years, high instances of pregnancy complications in previous years, and lacked existing care facilities? If you complete a survey to get this data, search a GIS database for buildings for sale or lease and combine all of it into a map, you would have a great idea of potential sites for facilities.
The beauty of GIS when applied to global health is that it scales easily, in geographic terms and the scope of its intended. Maps can be created to show trends and prevalence on scales as small as acre and as large as a continent or the globe. Analysis can be done to find relationships of various kinds and provide solutions to broad issues and those with well defined boundaries. GIS is one of the tools global health practitioners can use to track disease outbreak and target locations for increased prevention efforts and primary care.
It should be noted that anyone intending to use GIS most avoid making inappropriate judgement or mistakenly asserting causal relationships when they do not exist. Choice of preference for geographic boundaries and data sources, along with personal biases, can have a significant impact on the usefulness of GIS as a tool for decision making and communication.
If you are interested in seeing what an organization, in this case WHO, can do using GIS to help eliminate leprosy, I suggest you click here:
http://www.who.int/lep/monitor/gis/en/
If you are interested in seeing examples of global heath maps created using GIS, take a look at some of these:
http://www.psi.org/sites/default/files/publication_files/Using_GIS_Maps_for_healht_marketing_March2012_GW_publication.pdf
You are right Matt. GIS is now being extensively used to map diseases/ terrains/ habitations/ infections; in fact there are even more innovations like making a fear map for a city. Check this out:- http://www.mentalmaps.info/
ReplyDeleteI attended this presentation where the researcher was mapping the geographical location of communities and their medical service utilization to draw conclusions about which kind of hospital service service attracts which kind of consumer and other insights. GIS is also being used to map disease hot spots.