The Black Death - Modern Nightmare?

Could the Black Death return and become a modern killing nightmare?

In the first part of this article last week, we investigated The History of the Black Death and saw that people (correctly) recognised instantly that the Black Death was directly infectious, person-to-person. The first and obvious question now is: what was the nature of the infectious agent that was responsible for so much death and agony and terror? Since it disappeared 300 years ago, this is not an easy question to answer. The scent has gone cold. We must act as historical detectives and search for possible clues.

The one piece of hard quantitative evidence is the 40-day quarantine that was established with complete certainty and which indicates that the disease had a long incubation period. The only other source of quantitative data are the English parish registers which have been maintained since about the mid-16th century. They are unique and invaluable because, from Elizabethan times, vicars were required by law to designate the burials of plague victims.

Plotting the weekly plague burials reveals that all the major epidemics in England lasted some eight or nine months – a long time for an infectious disease and again indicative of a long incubation period. From computer modelling, we estimated this to be about 35 days.

For the last ten years we have studied scores of parish burial records and describe this work in detail in our book Return of the Black Death (see below). From our analyses, it became abundantly clear that this was, indeed, a directly infectious disease that spread in an invariable pattern. In particular, by studying the intervals between successive deaths in a line of infection, we were able to determine accurately its basic characteristics.