Home Science & Technology Viking Poop Helps Scientists Reconstruct Genome of Ancient Human Parasite: ScienceAlert

Viking Poop Helps Scientists Reconstruct Genome of Ancient Human Parasite: ScienceAlert

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A deep dive into the toilets of the past has given us new insight into the relationship between humans and the worms that love us.

By extracting DNA from a number of sources, including “archaeologically determined latrines” used by Vikings up to 2,500 years ago, researchers have reconstructed the genome of one of the oldest known human parasites.

The obtained data show that the worm (Trichuris trichiura) has been living with humans and adapting to them for at least 55,000 years.

New information about the biology and behavior of these tricky little parasites, researchers say, will help develop methods to prevent their spread.

“In people who are malnourished or have weakened immune systems, the worm can cause serious illness,” says zoologist Christian Kapel from the University of Copenhagen.

“Our mapping of ringworm and its genetic development facilitates the development of more effective anti-worm drugs that can be used to prevent the spread of this parasite in the poorest regions of the world.”

Although this worm is now rare in industrialized parts of the world, it is estimated to have infected up to 795 million people worldwide. According to the Center for Disease Controlespecially in regions with poor sanitation.

Its eggs are passed in human feces; they can be transferred fecal-oral routewhen contaminated faeces enter soil or water, which is then ingested by another host.

Once safe in the gut of a new host, the egg hatches and the female worms will continuously lay eggs at a rate of up to 20,000 per day once they reach maturity. They can live up to a year, thus producing huge numbers of offspring which are then excreted in the faeces to continue the cycle.

“Eggs lie in the ground and develop for about three months. Once matured, the eggs can survive in the wild for even longer, waiting to be swallowed by a new host, in whose digestive tract they will then hatch.” – explains Kapel.

“Their entire life cycle is adapted to survive in the soil as long as possible,”

It is this stability in the soil that allowed the team to sequence ancient DNA found in ancient fossilized human feces. Eggs have a shell made of hard chitin, which preserves the DNA contained in it, adapted for long survival in the soil environment.

In this way, the researchers were able to sequence only the eggs, and not the dried bodies of the mature worms, obtained from the Viking settlements in Vyborg and Copenhagen, as well as from sites in Latvia and the Netherlands.

A total of 17 different ancient samples were examined under a microscope to isolate the eggs, which were then sifted from the surrounding matrix of fossilized feces and subjected to genetic analysis.

The team also examined modern human samples from around the world, as well as monkeys, to compare them to ancient genomes.

“Unsurprisingly, we can see that the Vlachs seem to have spread out of Africa into the rest of the world with humans around 55,000 years ago, according to the so-called ‘out of Africa’ hypothesis of human migration,” – says Kapel.

The results suggest that the parasite has adapted to work with the human body, not against it, to remain undetected, live out its life cycle, and spread to as many hosts as possible.

It is also possible that, at least in some cases, a mild infection with a hairyhead can have a beneficial effect on a healthy host. Research has shown, for example, that hairy pigs increases the diversity of healthy gut bacteria and reduces the number of bacteria associated with poor pig health.

But with a severe infection, the consequences are much more unpleasant, including dysentery, anemia and rectal prolapse, and in children can interfere with healthy growth. The researchers say this new study could help create new tools to prevent this.

“In the Viking Age and the Middle Ages, there were not very sanitary conditions or well-separated areas for cooking and toileting,” – says Kapel.

‚ÄúThis gave the worm a much better opportunity to spread. Today it is very rare in industrialized parts of the world. Unfortunately, favorable conditions for its spread still exist in less developed regions of the world.”

The study was published in Communications of nature.

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