Scientists Discover Extinct Yesrsinia Strain That Caused The Black Death
An extinct strain of Yesrsinia pestis killed 30 to 50 million people from 1348 to 1351 in the pandemic known as The Black Death, an international team of researchers has discovered.
Until now, scientists have never been certain of what caused the plague which wiped out more than a third of Europe’s population in five years. Previous tests indicating the bacterium as the source were dismissed as contaminated by modern DNA. And scientists have long doubted that Yersinia, which, in its current forms, is slower to spread and less deadly than its medieval ancestor, could be a plague maker.
The team used a technique called “molecular fishing” to confirm the pathogen’s identity. “That indicates that at least this part of the genetic information has barely changed in the past 600 years,” says Johannes Krause, a member of the team.
Black Death was so called because skin covering large welts that spread across the victims’ bodies turned black. Symptoms also included acute fever and bloody vomit. Most victims died within two to seven days after infection.
More than 600 years later, Yersinia strains are milder but are still a threat to public health. This summer, a Yersinia enterocolitica outbreak associated with bottled milk and ice cream from Brunton Dairy in Pennsylvania sickened 16 people. Brunton Dairy makes home deliveries and sells milk and ice cream to retailers in Western Pennsylvania. The Pennsylvania Department of Health and the Allegheny County Health Department have issued a joint health advisory.
Yersinia enterocolitica bacteria causes diarrhea (often bloody), abdominal pain, nausea and vomiting and can sometimes enter the bloodstream and affect other organs. Onset of illness usually occurs four to seven days after exposure, but can be as short as one day or as long as two weeks. The bacteria can cause severe infections and the illness can mimic appendicitis and sometimes leads to unnecessary surgery. In a small proportion of cases, complications such as skin rash, joint pains, or spread of bacteria to the bloodstream can occur.
Sources: 1. http://www.uni-tuebingen.de/en/landingpage/newsfullview-landingpage/article/bakterium-yersinia-pestis-zweifelsfrei-als-erreger-des-schwarzen-todes-belegt.html
2. http://www.dnaindia.com/health/report_today-s-plague-pathogen-was-also-the-cause-of-black-death-600-years-ago_1582120
