LIVERPOOL, ENGLAND—An inherited deficiency in alpha-1-antitrypsin (A1AT) can contribute to the onset of the debilitating illnesses of chronic obstructive pulmonary disease (COPD) and emphysema. A1AT protects the lungs and liver from enzymes produced by the immune system, but those enzymes, called proteases, are also produced by parasitic worms. Richard Pleass of the Liverpool School of Tropical Medicine and a team of scientists say that deviant forms of A1AT evolved in Viking populations more than 2,000 years ago to combat worm infestations. “Vikings would have eaten contaminated food and parasites would have migrated to various organs, including lungs and liver, where the proteases they released would cause disease,” he said in a press release. “Thus these deviant forms of A1AT would have protected Viking populations, who neither smoked tobacco nor lived long lives, from worms. It is only in the last century that modern medicine has allowed human populations to be treated for disease-causing worms. Consequently these deviant forms of A1AT, that once protected people from parasites, are now at liberty to cause emphysema and COPD,” he explained. To read more about Vikings, go to "Vengeance on the Vikings."