A study published in the journal Nature Communications confirmed previous findings that the emergence of TB in Peru likely came from marine mammals such as seals and sea lions.
DNA research has shown that Mycobacterium pinnipedii, which today causes tuberculosis (TB) primarily in pinnipeds, infected human populations living in the coastal areas of Peru prior to European colonisation
The earliest cases are found in Peru and northern Chile and are dated to ~700 CE, with possible cases occurring as early as 290 CE.
The researchers also discovered TB in the skeletons of people who lived nowhere near the coast some 400 to 1,000 years ago — a scenario incompatible with TB transmission directly from infected pinnipeds or their tissues.
The results indicate that the infections were not the result of direct transmission from seals, but were caused by one or more spillover events -- when a pathogen moves from one species to another.
"M. pinnipedii could have been brought inland via animal life. Or in a more likely scenario, it could have been brought inland via human-to-human transmission facilitated by trade routes, or a combination of both."