Black Death: A case of the medieval plague with symptoms of coughing up blood and pus-filled boils detected in the U.S. --Plus, all the signs and symptoms of the medieval disease | 5 July 2024 | A new case of the dreaded bubonic plague has been detected in the U.S. The horrifying disease which can leave sufferers coughing up blood was responsible for the Black Death in medieval Europe and killed millions of people. Local officials said it's unclear how the unnamed person in [Pueblo County] Colorado contracted the disease, though it's usually spread through bites from fleas and infected animals. Scientists have previously found samples of the bacteria living in squirrels in the state... Plague is an infectious disease caused by a specific type of bacterium called Yersinia pestis. Y. pestis can affect humans and animals and is spread mainly by fleas.