Exponential growth is a concept that we often have to communicate in infectious disease control. For me its the concept that makes measles so terrifying. Each disease (under various circumstances) has its own reproduction number, otherwise know as R<sup>0</sup> (pronounced R-Nought). This is the number of people on average each infected person will go on to infect. If the number is bigger that 1 the outbreak continues of it is smaller than 1 the outbreak will start to draw to the end. 

The Ebola outbreak in 2014/15 had and R<sup>0</sup> of 2, this made it similar to the grains of rice on the chess board. Measles on the other hand has an R0 of between 14-18! Measles kills around 1 out of ever couple of children it infects and causes a great deal of suffering for those it doesnt. This is why we care so much about having a measles vaccination rate of 95% if we didn’t it would spread like wild fire. 

Here’s hoping the Steemit (a good disease that I’m happy I caught) has a high R<sup>0</sup>!