Caught in a wrenching cycle of shivering cold, high fevers, and profuse sweats, ecologist Michael Fay struggles through yet another attack of malaria at the Bomassa camp in Congo. Taking regular doses of antimalarial drugs can have long-term side effects, such as hearing loss and liver and kidney damage. So Fay, who has worked in Africa for decades, tends to wait until he feels achy and queasy before medicating himself. It's a risky approach that has twice come close to killing him.