Recent Research on the Black Plague

A while back, I had written about the black plague. Here is an article discussing conclusions reached from genetic comparisons between the Medieval Black Death and modern strains of the plague. The researchers here concluded that there are no significant genetic differences between the Medieval strain and modern strains that would explain why the Medieval strain was more virulent. The researchers advanced several hypothesis, however, including: (1) Europeans were more susceptible to plague because of increased hunger and lowered disease resistance due to a changed climate (cooler and wetter); (2) Europeans were more susceptible to the plague because of lack of prior exposure to the same or similar diseases; or (3) the plague virus may have acted in conjunction with another infectious agent.

The first two hypothesis are unsatisfactory because they do not address the virulence of the plague across all strata of society, as well as its apparently equal or greater virulence in the Middle-East and China. The second hypothesis is also unsatisfactory because Europeans (or some of them) would have had exposure to plague either through trade with Asia, and because Europe had previously been exposed to virulent outbreaks of plague, such as Justinian's plague. The third hypothesis may have merit, but no other candidates have ever been identified. Fortunately, this is not an area where "the science is settled."