The malaria parasite and its human hosts are locked in an evolutionary arms race. The parasite kills more than a million people every year. Humans fight back with gradual genetic adaptation and better drugs. The parasite then adapts to evolve drug resistance. Watch as immunologist Dyann Wirth and her team at the Harvard School of Public Health study the evolutionary adaptations of Senegalese people and their malaria parasites in the field and in the lab. The scientists are seeking signs of natural selection at a molecular level to help fight malaria in a smarter way.