Viking Poop Reveals One Of The Oldest Human Parasites

The mighty Viking poop has survived the vagaries of weather, and so have the parasitic eggs in it. DNA analysis of the feces has provided in-depth knowledge about one of the oldest parasites ever discovered.

The parasite found is the whipworm, scientifically called Trichuris trichiura. The study, published in the journal Nature Communications, provides insight into the parasite's development and prehistoric dispersal.

The findings of the team will aid in arresting the parasite's drug resistance, and also its future expansion across the human and non-human populations.

Whipworm, today, is not a cause of concern for developed industrialized countries. However, it still exists in developing countries with rudimentary sanitation facilities.

"During the Viking Age and well into the Middle Ages, one didn't have very sanitary conditions or well-separated cooking and toilet facilities. This allowed the whipworm far better opportunities to spread. Today, it is very rare in the industrialized part of the world. Unfortunately, favorable conditions for spreading still exist in less developed regions of the world," co-author Christian Kapel of the University of Copenhagen's Department of Plant and Environmental Sciences said.

Still, whipworm infection is not to be taken lightly. It can have an adverse impact on people with compromised immune systems.

"In people who are malnourished or have impaired immune systems, whipworm can lead to serious illness. Our mapping of the whipworm and its genetic development makes it easier to design more effective anti-worm drugs that can be used to prevent the spread of this parasite in the world's poorest regions," Kapel commented.

The fact that these whipworm eggs survived for so long can be attributed to their sturdy capsules. The egg capsules have robust chitin material, which has preserved the internal DNA of thousands-of-years-old whipworms. Also, the eggs were buried in moist soil, which helped in their preservation.

Fossilized feces were extracted from latrines of Viking settlements in Viborg and Copenhagen. Gross as it may sound, the research team sifted the stool to isolate eggs, after which they were put under a microscope. The eggs went through refined genetic analyses.

"We have known for a long time that we could detect parasite eggs up to 9,000 years old under a microscope. Lucky for us, the eggs are designed to survive in the soil for long periods of time. Under optimal conditions, even the parasite's genetic material can be preserved extremely well," Kapel explained.

"And some of the oldest eggs that we've extracted some DNA from are 5,000 years old. It has been quite surprising to fully map the genome of 1,000-year-old well-preserved whipworm eggs in this new study."

The fossilized stool samples were compared with modern whipworm samples from infected people. This provided the scientists with an overview of the worm's evolution over tens of thousands of years.

"Unsurprisingly, we can see that the whipworm appears to have spread from Africa to the rest of the world along with humans about 55,000 years ago, following the so-called 'out of Africa' hypothesis on human migration," Kapel said.