The geography of medicine


Yesterday, looking at comments on an article on Facebook about the intensifying fight between supporters of vaccinations and foes. I saw that there were some who seemed to honestly not understand how the dispersal of these diseases works. And I wondered if a lesson in how epidemiology was founded, coupled with a brief foray into medical geography would assist.

I am reminded of a lesson in medical geography that I took when I was at University of Canterbury. Medical geography looks at the temporal and spatial distribution of illness, the environment that causes that distribution and ways of addressing it. The lesson looked at an example from 1850’s England when there was a cholera outbreak. It was a very localized outbreak. English physician John Snow, who had conducted research into the disease became interested. He looked at the distribution of instances by talking to local residents and ascertaining which wells they were using. Once it was established that rates were particularly bad in an area around Broad Street, he looked at where the water was being sourced from and noted that it was being drawn from a polluted section of the Thames River. He established that the deaths from the cholera outbreak were concentrated around a particular well, and employed a dot map to show this.

In a modern society with vehicles and aircraft able to give people a local mobility that simply did not exist 100 years ago when the Influenza pandemic that was spread by soldiers returning from World War 1, only one person needs to be infected to establish an outbreak in a new location. Soldiers living in absolute squalor in the front line trenches where hygiene was effectively non-existent became incubators for a particularly virulent variation that would go on to affect 500 million people world wide; kill nearly 100 million people and devastate families and communities alike. With an aircraft flight able to cover reach any major New Zealand town within two hours a case that originated in Auckland may have infected someone living in Dunedin before the day is out.

In African countries Ebola is a disease that was discovered in 1976 and is thought to be hosted by fruit bats. Currently afflicting western African nations, Ebola has an average mortality rate of about 50%, though this can vary anywhere between 25% and 90% in individual outbreaks. It spreads from contact with fruit bats, chimpanzees, gorillas, antelope, porcupines and monkeys found dead in the forest.

The virus is spreading in Africa because of a chronic underfunding of health care and education. Basic hygiene levels are very poor, which means humans who have had contact with patients are becoming potential incubators of it themselves. The symptoms start to show between 48 hours and 3 weeks after the contact with the body or body fluids of a person who has died.

But New Zealand is not like Africa. Aside from much better education, medical care and planning for such diseases, our authorities are much more transparent in terms of what information they hold and how they use it. Yet we have an escalating problem with vaccination caused by people who are either wilfully ignorant or not educated to understand that the science behind vaccinations is well grounded and with the best intentions. Thus decades of hard work trying to eradicate Measles Mumps and Rubella from our fair land is being undermined.

As far as I know there is no geographical field that can understand the the temporal and spatial dispersal of wilful ignorance.