[Northkeep] Black Death not Bubonic Plague?

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Source:        Penn State
               (http://www.psu.edu/)
Date Posted:   Monday, April 15, 2002
Web Address:
http://www.sciencedaily.com/releases/2002/04/020415073417.htm

MEDIEVAL BLACK DEATH WAS PROBABLY NOT BUBONIC PLAGUE

The Black Death of the 1300s was probably not the modern disease known
as bubonic plague, according to a team of anthropologists
studying on these 14th century epidemics.

"Although on the surface, seem to have been similar, we are not
convinced that the epidemic in the 14th century and the present day
bubonic plague are the same," says Dr. James Wood, professor of
anthropology and demography at Penn State. "Old descriptions of
disease symptoms are usually too non-specific to be a reliable basis for
diagnosis."

The researchers note that it was the symptom of lymphatic swelling that
led 19th century bacteriologists to identify the 14th century
epidemic as bubonic plague.

"The symptoms of the Black Death included high fevers, fetid breath,
coughing, vomiting of blood and foul body odor," says Rebecca
Ferrell, graduate student in anthropology. "Other symptoms were red
bruising or hemorrhaging of skin and swollen lymph nodes. Many
of these symptoms do appear in bubonic plague, but they can appear in
many other diseases as well."

The researchers, who also include Sharon DeWitt-Avina, Penn State
graduate student in anthropology, Stephen Matthews and Mark
Shriver, both professors in the Population Research Institute at Penn
State, and Darryl Holman, assistant professor of anthropology,
University of Washington, Seattle, are investigating church records and
other documents from England to reconstruct the virulence,
spacial diffusion and temporal dynamics of the Black Death.

They are looking especially closely at bishops' records of the
replacement of priests in several English dioceses. Although these
records
are often incomplete and difficult to interpret, they clearly show that
many priests died during the epidemic period of 1349 to 1350.

"These records indicate that the spread of the Black Death was more
rapid than we formerly believed," Wood told attendees today
(April 12) at the annual meeting of the American Association of Physical
Anthropologists in Buffalo, N.Y. "This disease appears to
spread too rapidly among humans to be something that must first be
established in wild rodent populations, like bubonic plague. An
analysis of the priests' monthly mortality rates during the epidemic
shows a 45-fold greater risk of death than during normal times, a level
of mortality far higher than usually associated with bubonic plague."

Modern bubonic plague typically needs to reach a high frequency in the
rat population before it spills over into the human community via
the flea vector. Historically, epidemics of bubonic plague have been
associated with enormous die-offs of rats.

"There are no reports of dead rats in the streets in the 1300s of the
sort common in more recent epidemics when we know bubonic
plague was the causative agent," says Wood.

Instead of being spread by animals and insect vectors, the researchers
believe that the Black Death was transmitted through
person-to-person contact, as are measles and smallpox. The geographic
pattern of the disease seems to bear this out, since the disease
spread rapidly along roadways and navigable rivers and was not slowed
down by the kinds of geographical barrier that would restrict
the movement of rodents.

"It is possible that the Black Death was caused by any of a number of
infectious organisms, but we are not ready to pinpoint the
causative agent," says Wood. "The Black Death was too quickly identified
with bubonic plague in the past. Indeed, historians took what
was known about the bubonic plague and used it erroneously to fill in
the many gaps in our picture of the Black Death. We do not want
to make the same mistake by identifying some other possible cause
prematurely."

The researchers do not rule out the possibility that the Black Death
might have been caused by an ancestor of the modern plague
bacillus, which might later have mutated into the insect-borne disease
of rodents that we now call bubonic plague. The fact is that we can
only trace modern bubonic plague reliably back to the late 18th century
or early 19th century, according to Wood. Who knows when it
first emerged?

"We too often make the assumption that while a lot of things change in
the interaction of infectious diseases and human hosts, the
microbe itself stays more or less the same," says Wood. "This is wrong.
If anything is likely to change, it is a microbe that goes through
millions of generations and an equal number of chances to mutate over a
few centuries. We see no reason to think that the Black Death
pathogen still exists in anything like its original form."