Neanderthal extinction may have been caused by infectious diseases that Homo sapiens or humans carried. Researchers at Cambridge and Oxford Brookes universities, who analyzed ancient samples of DNA, said that there is no clear evidence that the transmission of diseases killed off the Neanderthals. Other factors such as competition over sources of food may have played a role.

The study is published in the American Journal of Physical Anthropology. Humans who migrated out of Africa to Europe may have been carrying diseases like herpres, tuberculosis, stomach ulcers and other chronic conditions that may have been fatal to Neanderthals.

"Humans migrating out of Africa would have been a significant reservoir of tropical diseases. For the Neanderthal population of Eurasia, adapted to that geographical infectious disease environment, exposure to new pathogens carried out of Africa may have been catastrophic," Dr. Charlotte Houldcroft from the Division of Biological Anthropology at Cambridge said, Medical News Today reports.

The outlet notes that Homo sapiens and Neanderthals came from a common ancestor. When humans migrated to Europe from Africa, Neanderthals went extinct after a couple of thousands of years. The interbreeding of humans and Neanderthals may have initiated the transmission of infectious diseases. The infected Neanderthals would have been weakened and thus, unable to hunt food and survive.

"As we now know that humans bred with Neanderthals, and we all carry 2 to 5 percent of Neanderthal DNA as a result, it makes sense to assume that, along with bodily fluids, humans and Neanderthals transferred diseases," said Houldcroft, Washington Post notes.

The study also reveals that infectious diseases including tuberculosis and herpes may be as old as humans. It was previously believed that numerous infectious diseases surfaced with the introduction of agriculture and breeding of livestock among humans.

Do you think that the infectious diseases brought by humans are what caused Neanderthals to go extinct? Tell us your thoughts in the comment section below.