Herpes is forever – and has been for a long, long time.
Humans migrating out of Africa may have spread the genital herpes virus,as well as tuberculosis, tapeworm and other diseases, to Neanderthals in Europe and Asia more than 50,000 years ago.
Researchers at Cambridge and Oxford Brookes universities analyzed ancient DNA and pathogen genomes from fossilized bones and discovered that our Homo sapien ancestors carried these infectious tropical diseases when they began interacting and sometimes mating with our hominin cousins.
The report published in the American Journal of Physical Anthropology on Sunday also suggests that the Neanderthals had no natural immunity for these new diseases, which likely led to their mysterious extinction 40,000 years ago.
“Humans migrating out of Africa would have been a significant reservoir of tropical diseases,” said Dr Charlotte Houldcroft, one of the study’s authors, in a release. “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.”
The diseases didn’t decimate populations the way smallpox wiped out the Native Americans exactly.
“It’s more likely that small bands of Neanderthals each had their own infection disasters, weakening the group and tipping the balance against survival,” said Houldcroft.
The new evidence gleaned by her team concludes that some of these infectious diseases are thousands of years older than previously suspected.
The old school of thought suggested infectious diseases spread 8,000 years ago as the dawning of agriculture led humans to settle down and live in close proximity to each other and livestock, which created “a perfect storm” for diseases to spread.
The new evidence suggests disease had a longer “burn in period” predating agriculture.
That includes the herpes simplex 2 virus, which causes genital herpes, believed to have been first transmitted to humans in Africa 1.6 mllion years ago from another, currently unknown human species.
And helicobacter pylori, the bacterium behind stomach ulcers, is estimated to have first infected humans in Africa 88 to 116 thousand years ago, and arrived in Europe after 52,000 years ago, according to the report.
“Hunter-gatherers lived in small foraging groups. Neanderthals lived in groups of between 15-30 members, for example. So disease would have broken out sporadically, but have been unable to spread very far,” said Houldcroft. “Once agriculture came along, these diseases had the perfect conditions to explode, but they were already around.”