Viking Poop Yields New Insights into Ancient Parasite

Using stool samples from Viking latrines, researchers at the University of Copenhagen and Wellcome Sanger Institute have genetically mapped whipworm—one of the oldest known human parasites—and uncovered completely new knowledge about the parasite's development and prehistoric dispersal. This knowledge can be applied in efforts to prevent the parasite's drug resistance and its future spread.

Though whipworm, or Trichuris trichiura, is now rare in industrialized countries and most often only causes minor problems among healthy individuals, the parasite is estimated to affect 500 million people in developing countries.

"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," says Professor Christian Kapel of University of Copenhagen’s Department of Plant and Environmental Sciences.

The study, published in Nature Communications, evaluated fossilized whipworm eggs from 2,500-year-old feces found at Viking settlements in Denmark, Latvia, and the Netherlands. The study suggests that human and parasite have developed a delicate interaction over thousands of years, whereby the parasite tries to stay “under the radar” not to be repelled, which allows it more time to infect new people. From other studies, it is known that the whipworm stimulates the human immune system and the gut microbiome, to the mutual benefit of both host and parasite.

The researchers examined archaeological stool samples from several locations. These ancient genetic samples are compared with contemporary samples obtained from people with whipworms from around the world. Doing so has provided researchers with an overview of the worm's genome and its evolution over ten-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 adds.