Calculus in Medicine
When I thought of calculus, I used to think of maths. And physics. And engineering. Which is why I found these lines in Steven Strogatz’s Infinite Powers very, very surprising: “Consider the surprising role that differentials (calculus) played in the understanding and treatment of HIV.” Back then, it was known that HIV went through 3 stages: 1) In the first stage, an infected person has flu-like symptoms; 2) Next, a 10-year period of no symptoms; 3) And finally, AIDS sets in, weakening the immune system to a point where other infections overwhelm the system and kill the patient. Tests had shown that the number of virus particles in the bloodstream was high in the first stage (hence the symptoms); was low but not gone altogether (the “set point”) in the second stage; and was overwhelming in the last stage. With no cure in sight, all kinds of ideas were tried. One such team was of...