Migrating humans may have killed off Neanderthals by accident

Story highlights

  • Study suggests Neanderthal extinction linked to diseases carried from Africa by humans
  • Infections likely to have been passed to Neanderthals include tapeworm, tuberculosis, stomach ulcers, types of herpes

(CNN)It appears modern humans may have some blood on our hands. A new study published in the American Journal of Physical Anthropology suggests that Neanderthals may have gone extinct because of tropical diseases carried by humans migrating out of Africa.

"Humans migrating out of Africa would have been a significant reservoir of tropical diseases," said lead author, Charlotte Houldcroft from the University of Cambridge's Division of Biological Anthropology, in a statement. "For the Neanderthal population of Eurasia, adapted to that geographical environment, exposure to new pathogens carried out of Africa may have been catastrophic."
Researchers at Cambridge and Oxford Brookes universities analyzed DNA from ancient bones and pathogen genomes. They concluded that some infectious diseases are probably thousands of years older than previously believed.
There is evidence that humans caught viruses from other hominins before moving out of Africa. There is even evidence that our human ancestors mated with Neanderthals thousands of years ago and exchanged disease-related genes. So researchers argue that it's safe to say humans could have passed diseases on to Neanderthals when they moved into Europe.
"As we now know that humans bred with Neanderthals, and we all carry 2% to 5% of Neanderthal DNA as a result, it makes sense to assume that, along with bodily fluids, humans and Neanderthals transferred diseases," said Houldcroft.
Infections likely to have been passed from humans to Neanderthals include tapeworm, tuberculosis, stomach ulcers and types of herpes, according to the study.