Posted on behalf of Ashley Yeager

Cows can no longer take the blame for being the first to spread TB to humans.

Scientists long thought humans contracted the disease roughly six thousand years ago when drinking infected cattle’s milk. But the discovery of two much older human TB victims—a mother and a child who died 9,000 years ago – disproves this notion.

Bones from the mother and child were discovered off the coast of Haifa, Israel in a Neolithic village now submerged by the sea. Looking at the fossils hinted that the mother and child once carried active TB infections. But to verify this, Helen Donoghue of the University College London and her team extracted DNA from the bones and tested them for any telltale signs of the disease.

Surprisingly, “the only strains that turned up boasted the tell-tale signature of human tuberculosis, not a cow or other animal strain,” Donoghue told New Scientist. https://www.newscientist.com/article/dn14941-oldest-cases-of-human-tb-found-beneath-the-sea.html?DCMP=ILC-hmts&nsref=news4_head_dn14941

That means “it was not animals that infected humans, it was humans infecting humans,” which suggests that humans settling in packs, rather than humans domesticating animals, led to the spread of the disease, she told the Telegraph.

Donoghue and her UK and Israeli colleagues reported their findings in PLoS One online on 15 October. They hope that further DNA analysis from this and other ancient TB cases will continue to give scientists clues about how the bacterium that causes the disease has evolved over thousands of years and about how it may change in the future.

“This then helps us improve our understanding of modern TB and how we might develop more effective treatments,” Mark Spigelman, also a coauthor of the study from University College London, said in a press release.

Image: National Tuberculosis Association ‘What You should know about Tuberculosis’ pamphlet cover, via NIH.