Many thousands of years ago, on a chilly African night, a group of people gather around a fire in a cave. Using the flames, they cook their food, fashion new weapons, and warm themselves. But where there’s fire, there’s also smoke, and the smoke is giving the huddled humans a wretched cough. And in their inflamed airways, a microbe that normally lives in the soil is taking hold, changing, evolving into something new.

It is never a good time to come down with tuberculosis, but in recent years the outlook has become worse.

The search for new treatments for infectious diseases gets a lot of attention. But to treat something, we first need to know what we’re dealing with. That’s not always easy. The backbone of diagnosis is still built from old methods that include growing mystery germs in lab cultures, or checking how they react to specific chemicals. These techniques require special training and can be time-consuming. Unlike medical dramas, where diseases can be diagnosed between quips, the real-life work can take days.