Disease-causing microbes often mutate and develop drug resistance. For example, the malaria parasite has adjusted to make one once-effective and inexpensive treatment no longer viable in many places. Countries now are turning to alternative malaria treatments, which can be more than 20 times as expensive. Malaria claims more than 1 million lives annually.

Recent advances in evolutionary biology have suggested new approaches to developing medicines that would be harder for microbes to resist.