
Researchers suggest that intestinal parasites in Vikings might have increased the risk of asthma, emphysema, and similar respiratory conditions in their present-day descendants. The study was detailed in last month's edition of the journal Scientific Reports.
Although parasites from ancient times are well-documented, the specific worms found in Vikings are a recent revelation. In a study last year, experts analyzed 1000-year-old fecal matter from a Viking latrine and identified three distinct types of intestinal parasites.
"This additional layer of insight is incredibly thrilling for archaeologists," said Søren Michael Sindbæk, a professor and archaeologist, in an interview with Science Nordic. "It opens up possibilities to address questions that were previously beyond our reach."
He was correct. According to the new study, these parasites altered the DNA of Vikings, which in turn influenced the genetic makeup of their descendants, making them more susceptible to lung-related ailments.
Richard Pleass, a parasite expert and the study's senior author, along with his team, focused on how antibodies known as immunoglobulin E (IgE) interact with the protein alpha-1-antitrypsin (A1AT).
The team gathered plasma samples from individuals currently infected with the parasites and analyzed them to observe interactions between IgE and A1AT. They discovered that a specific variant of the A1AT gene was particularly effective in combating diseases caused by the parasites. Vikings possessing this gene variant had higher survival rates and were more likely to pass it on to their offspring.
However, this gene variant has a dual effect. In modern times, individuals born with this variant are more prone to A1AT deficiency, increasing their risk of developing conditions like emphysema, asthma, and chronic obstructive pulmonary disease (COPD). This deficiency is most prevalent among Scandinavians.
"It is only in the last century that modern medicine has enabled the treatment of parasitic infections in humans," Pleass stated in a press release. "As a result, these atypical forms of A1AT, which once protected people from parasites, now contribute to the development of emphysema and COPD."
While A1AT deficiency is treatable, identifying its presence is the first step. Both the Alpha-1 Foundation and the World Health Organization advise genetic screening for individuals diagnosed with COPD, bronchiectasis, or asthma that does not respond to standard treatments.
