Biology of Plagues: Evidence from Historical Populations (review)

Biology of Plagues: Evidence from Historical Populations, by Susan Scott and Christopher J. Duncan. Cambridge, UK: Cambridge University Press, 2001. $100, cloth.

The names of Susan Scott and Christopher Duncan need no introduction for those of us interested in time series analysis of epidemics. Indeed, their 1998 book titled Human Demography and Disease is an excellent source on spectral analysis of time series, one that I consult frequently. However, the title of their newest book, Biology of Plagues, is somewhatmisleading, since it deals with epidemics during a specific time and place, namely, Western Europe from 1300 to the 1660s. Even so, the authors present a persuasive and well-documented case that these epidemics were not outbreaks of bubonic plague, as has been assumed in the past.

The book has a nice introduction that reviews the history of plagues in the western world, although it never answers the question of what a plague actually is. The introduction also reviews the danger of emerging pestilences, and defines basic terms such as populations, meta-populations, and so forth. The second chapter includes methodological issues such as transmission probability and spatial components of epidemics.

The rest of the book consists of reviews of specific case studies (such as the plague at Penrith in 1597-1598, at Eyam in 1665-1666, at Marseilles in 1720- 1722, and plagues in France and Italy). And what reviews they are! The detective, historical, demographic, and archival research that went into these chapters amazed me. For several epidemics, Scott and Duncan reconstruct the actual sequence of deaths, including the people's names, the location of the households, and even their wills and the location of their burials. These chapters are accompanied with clear charts that indicate who died and in what sequence, with possible infection routes among the households. Furthermore, they frequently cite the writings of the physicians who examined the patients, or the local lore about the cause of the epidemic. Page after page, I was impressed by the detailed work presented.

Scott and Duncan's narrative makes the topic appealing and engaging. It is fascinating to read the accounts about the epidemics, the way people behaved in response to them, and what was done to prevent further spread of the disease. The authors even look at which health measures taken by local officials were effectual or ineffectual.

As far as I am concerned, this book clearly establishes that the terrible hemorrhagic plagues from 1300 to the 1660s were not caused by Yersinia pestis. Scott and Duncan instead propose that the disease was probably caused by filoviruses similar to the one that causes the Ebola infection. A really intriguing part of their book is the authors' proposition that the filovirus might have selected for the CCR5 allele that appears to give some protection from HIV infection. This might explain the high frequency of the HIV-protective allele in European populations. Thus, by mentioning this piece of information, Scott and Duncan bring present-day relevance to the plagues of old.

For whom was this book written? According to the authors, Biology of Plagues could interest a wide variety of readers, but I am not sure I agree with them. I can't see using it as a textbook, in contrast to their 1998 book. It will be of some interest to general science readers because of the engaging description of the epidemics, the cultural context, and the health measures undertaken to stop it. At the same time, it is too technical to be easily accessible for them. I think the book would be of most interest to the readers of Human Biology who want to spice up their lectures on health and disease adaptation. I would also be curious to know if anybody uses it as a textbook. From a personal standpoint, I enjoyed this book tremendously, and congratulate Scott and Duncan for an outstanding piece of work.