Did Skanky Humans Do In the Neandertals?

Neanderthals may have been infected by diseases carried out of Africa by humans,

Review of latest genetic evidence suggests infectious diseases are tens of thousands of years older than previously thought, and that they could jump between species of ‘hominin’. Researchers says that humans migrating out of Africa would have been ‘reservoirs of tropical disease’ – disease that may have sped up Neanderthal extinction.

A new study suggests that Neanderthals across Europe may well have been infected with diseases carried out of Africa by waves of anatomically modern humans, or Homo sapiens. As both were species of hominin, it would have been easier for pathogens to jump populations, say researchers. This might have contributed to the demise of Neanderthals.

 Notice the weasel word "might."

Researchers from the universities of Cambridge and Oxford Brookes have reviewed the latest evidence gleaned from pathogen genomes and DNA from ancient bones, and concluded that some infectious diseases are likely to be many thousands of years older than previously believed.

There is evidence that our ancestors interbred with Neanderthals and exchanged genes associated with disease. There is also evidence that viruses moved into humans from other hominins while still in Africa. So, the researchers argue, it makes sense to assume that humans could, in turn, pass disease to Neanderthals, and that – if we were mating with them – we probably did.

What, no condoms?

Dr Charlotte Houldcroft, from Cambridge’s Division of Biological Anthropology, says that many of the infections likely to have passed from humans to Neanderthals – such as tapeworm, tuberculosis, stomach ulcers and types of herpes – are chronic diseases that would have weakened the hunter-gathering Neanderthals, making them less fit and able to find food, which could have catalysed extinction of the species.

“Humans migrating out of Africa would have been a significant reservoir of tropical diseases,” says Houldcroft. “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.”

“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,” says Houldcroft.

Oh, why not; we'll be blamed for it anyway. It could have gone the other way. We could have been eliminated by diseases acquired from Neandartals. And Denisovan's; what did they give us?

The researchers describe Helicobacter pylori, a bacterium that causes stomach ulcers, as a prime candidate for a disease that humans may have passed to Neanderthals. It is estimated to have first infected humans in Africa 88 to 116 thousand years ago, and arrived in Europe after 52,000 years ago. The most recent evidence suggests Neanderthals died out around 40,000 years ago.

Another candidate is herpes simplex 2, the virus which causes genital herpes. There is evidence preserved in the genome of this disease that suggests it was transmitted to humans in Africa 1.6 million years ago from another, currently unknown hominin species that in turn acquired it from chimpanzees.

So, if you have Herpes, you can blame some long lost ancestor who slept with a chimpanzee?

Wombat-socho has the giant "Rule 5 Sunday: Blue Shirt Double-Dip Edition" ready at The Other McCain.