The Mekong basin is teeming with life. Giant fish and crocodiles patrol the water, while thousands of birds fly through the air. The area’s biodiversity is among the richest in the world, and it is becoming more crowded. The basin stretches across 795 000 km2 of land, shared between China, Burma (Myanmar), Vietnam, Thailand, Laos, and Cambodia. It is home to an estimated 60-70 million people, mostly farmers, and this number is expected to increase to 120 million by 2025. These residents, and their livestock, are slowly encroaching into areas inhabited by wild animals—a clash of species that is turning the Mekong into a time bomb of disease. Within this throng of humans and animals, emerging infections can find plenty of