Neanderthals May Have Been Killed Off By Tropical Diseases Carried By Modern Humans

Neanderthals may have been died out after tropical diseases were introduced by waves of anatomically modern humans from Africa, new research suggests.

Evidence suggests that modern human ancestors bred with Neanderthals, exchanging genes associated with disease, according to researchers from universities of Cambridge and Oxford Brookes.

Infections such as tapeworm, tuberculosis and herpes would have weakened the hunter-gatherer Neanderthals, making them less fit and able to find food and leading to their demise, says the study.

“However, it is unlikely to have been similar to Columbus bringing disease into America and decimating native populations. It’s more likely that small bands of Neanderthals each had their own infection disasters, weakening the group and tipping the balance against survival,” explains Dr Charlotte Houldcroft, from Cambridge’s Division of Biological Anthropology.

While it is widely thought that infectious diseases exploded with the dawn of agriculture, the researchers believe that some diseases have been around for much longer and originated in humans and not herd animals, as originally thought.

“We are beginning to see evidence that environmental bacteria were the likely ancestors of many pathogens that caused disease during the advent of agriculture, and that they initially passed from humans into their animals,” says Houldcroft.

As yet, there is no hard evidence of infectious disease transmission between humans and Neanderthals, but given the timing and geography and the evidence of interbreeding, the researchers are convinced that it occurred.

“It is probable that a combination of factors caused the demise of Neanderthals,” says Houldcroft, “and the evidence is building that spread of disease was an important one.”

The study was published in the American Journal of Physical Anthropology.

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