Virus hunter Nathan Wolfe is outwitting the next pandemic by staying two steps ahead: discovering deadly new viruses where they first emerge — passing from animals to humans among poor subsistence hunters in Africa — before they claim millions of lives.

And in this talk, also by researcher Hans Rosling, new data visuals that untangle the complex risk factors of one of the world’s deadliest (and most misunderstood) diseases: HIV. He argues that preventing transmissions — not drug treatments — is the key to ending the epidemic.