The human story of cholera started in Asia

Cholera patients in a clinic in Harare, Zimbabwe, in January 2009. Photo: Tsvangirayi Mukwazhi / AP

The planet is in the midst of its seventh cholera pandemic — one that affects about 3 million people each year and, unlike past pandemics that faded away, persists. Stopping its spread hinges on tracking its movements.

By analyzing the genomes of bacteria isolated from samples collected during cholera outbreaks over the past half-century, scientists have now determined that outbreaks in Africa and the Americas were sparked by strains that arrived from Asia. Tracing the paths into and around these regions offers new targets for efforts to control the disease.