Pathogens are disease-causing microorganisms such as bacteria and viruses, and DNA evidence can determine the earliest traces of disease.DNA from northern Chile and southern Peru suggest that a cycle of Chagas’ disease was likely well-established by around 9,000 years ago to 1,500 years ago. The earliest known cases of human tuberculosis were found in the bones of a mother and baby, submerged off the coast of Israel around 9,000 years ago. This evidence provides insight into our evolutionary past and clues about how these diseases continue to evolve today. When humans and human ancestors migrated around the globe, they encountered new pathogens and brought some pathogens with them, creating new distributions of diseases.

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