Reuters North American News Service, January 29th, 2008
WASHINGTON (Reuters) - The Black Death that
decimated populations in Europe and elsewhere during the middle
of the 14th century may not have been a blindly indiscriminate
killer, as some experts have believed.
An analysis of 490 skeletons from a London cemetery for Black
Death victims demonstrated that the infection did not affect
everyone equally, two U.S. scientists said Monday.
While many perfectly healthy people certainly were cut
down, those already in poor health prior to the arrival of the
plague were more likely to have perished, they found.
"A lot of people have assumed that the Black Death killed
indiscriminately, just because it had such massive mortality,"
anthropologist Sharon DeWitte of the University at Albany in
New York, said in a telephone interview.
People already in poor health often are more vulnerable in
epidemics. "But there's been a tradition of thinking that the
Black Death was this unique case where no one was safe and if
you were exposed to the disease that was it. You had three to
five days, and then you were dead," DeWitte said.
The plague epidemic of 1347 to 1351 was one of the
deadliest recorded in human history, killing about 75 million
people, according to some estimates, including more than a
third of Europe's population.
DeWitte analyzed skeletons unearthed from the East
Smithfield cemetery in London, dug especially for plague
victims and excavated in the 1980s, for bone and teeth
abnormalities that would show that people had health problems
before they died of plague.
She found such abnormalities in many skeletons, suggesting
these people had experienced malnutrition, iron deficiencies
and infections well before succumbing to the Black Death.
The proportion of people with such signs of frailty in the
cemetery, compared to those who appeared to have been of robust
health before the epidemic, indicated that the infection was
somewhat selective in who it killed, DeWitte and Pennsylvania
State University anthropologist James Wood reported in the
Proceedings of the National Academy of Sciences.
Some experts have thought the Black Death -- named after
the black spots the bubonic form of the plague caused on the
skin -- killed indiscriminately regardless of age, sex or level
of health because it was so virulent and the European
population so immunologically unprepared, DeWitte and Wood
wrote.
"The Black Death was highly virulent and undoubtedly killed
many otherwise healthy people who would have been unlikely to
die under normal-mortality conditions," they wrote. But people
already in poor health were more likely to die, they wrote.
Many scientists think the plague was caused by Yersinia
pestis, a bacterial disease spread by fleas from rats. It still
kills between 100 and 200 people a year.
The Black Death pandemic thought to have begun in Asia,
then spread into the Middle East, Africa and Europe.
"On average, it killed between 30 to 50 percent of affected
populations. But we know that there were some areas where
mortality was even higher. So there would have been villages
that were completely wiped out," DeWitte said.
Other experts now think the Black Death may have been
caused not by bubonic plague but by a viral hemorrhagic fever,
similar to the disease caused by the Ebola or dengue viruses.
(Editing by Maggie Fox and Cynthia Osterman)
