Jessica Brehmer- Public Health Mapping

Jessica is currently a graduate student at the University of Minnesota School of Public Health and is employed by the Minnesota Department of Health. She has a BA in Geography from the University of Minnesota and is a former geography intern with NGS.

Mapping diseases goes way back. In the infamous Broad Street pump incident of 1854, John Snow mapped cases of cholera in a London neighborhood during an epidemic and noticed most cases were using water from the same pump. He removed the pump handle and the epidemic came to a halt. Now there is a whole field of study dedicated mapping diseases and health geographics, and I want in!

Maps easily show the distribution of diseases. This visualization of the distribution is useful for many applications in public health. For example, if you were planning a campaign to distribute mosquito nets in Africa to prevent malaria, a map would show you that malaria is not endemic in the Sahara desert as it is Sub-Saharan Africa. The map helps you prioritize net distribution to the highest risk areas. Such maps are relevant for all diseases across the field of public health.


I recently got my first opportunity to put my skills to use by mapping frequency and prevalence of hepatitis B and C. (Frequency is the number of cases in an area and prevalence is the ratio of number of cases by the population of an area.) I geeked out a little bit when my boss asked me to take on this task because I am finally able to combine geography and public health in a practical setting.

When the mapping was done, it was no surprise the highest number of cases of both hepatitis B and C were located in the largest cities. It was a big surprise, however, when I calculated the prevalence of hepatitis that some smaller counties had higher rates than metro areas. This means that more people per 1000, for example, have the disease. When we discover such surprises, we can hypothesize as to why such high rate would occur within a geographic region and do something about it.

I also learned a lot about the mapping process. The single most important part about mapping is the quality of data. The better the data are, the more accurately the map will depict the true scope of the disease. As I was joining the data for one of my maps, one of the northern counties disappeared! Our hypothesis about the county seceding to Canada gave us a few chuckles, but I knew there were some kinks in the data. Thankfully, it turned out to be an easy fix.

Now that I’ve completed my assigned maps I am thinking about new ways to map Hepatitis. So what do you think geoglings, how else could I represent Hepatitis on a map?

Now, if only I could find the proverbial pump to remove…

One thought on “Jessica Brehmer- Public Health Mapping

  1. Great reading your blog. That Iam from India, I could appreciate your work & relate to what you have mentioned.
    As and when there is an out break of Malaria in Chennai City , the capital of Tamil Nadu – State from Southern India .I take the trouble to visit the nearest physician to check what were the number of cases of Malaria for the day , week & month . I do this not just for Malaria but for all diseases & when there is an outbreak

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