# 4902
As I’ve pointed out many times in the past, science isn’t absolute, nor is scientific progress linear. Sometimes the things we think we `know’ turn out to be wrong.
Throughout history we’ve accounts of epidemics and plagues for which medical historians have tried to determine a cause. Some, like the high mortality `English Sweats’ of the 1500s, remain a mystery to this day.
Since viable tissue samples from victims hundred of years ago are rarely available, and contemporary medical science was practically non-existent, the case for some of these determinations is largely circumstantial.
Roughly 660 years ago a disease swept through Europe killing – in just a matter of five years – between a third and a half of the population. Some estimates put the toll at between 100 and 200 million deaths.
It was known as the `Black Death’, because of the characteristic dark bubboes (swelling of the lymph nodes) in the neck, armpit, and groin.
Over the next 500 years, more than 100 smaller outbreaks occurred across Europe and Asia.
For more than 100 years the cause of this horrific event has been widely accepted as coming from the bites of fleas carrying a bacteria called Yersinia pestis – which they acquired from infected rats.
Rats that arrived in Europe from the recently opened trade routes from the Orient, where Y. Pestis is endemic in small rodents (the bobak marmot).
This tidy, and widely accepted theory came from the research of scientists who visited Hong Kong in 1994 1894 to investigate an outbreak of plague. Among them was Alexandre Yersin, from whose name we get Yersina, or Y. pestis.
Over the next ten years, a theory on how the disease was vectored (rats to fleas to human) was developed.
In 1893, before this research began, historian F. A. Gasquet linked the Black Death of the 1300s to the modern outbreaks of plague. Fifteen years later, he was able to adopt the intervening research on Y. Pestis to complete his theory, which is widely accepted today.
Widely . . . but not universally accepted, that is.
For more than 40 years, contrarian voices have suggested that Y. Pestis – while the cause of modern plague – may not have been behind the Black Death of 660 years ago.
Additionally, new research strongly suggests that body lice might be another vector for Y. Pestis as well.
All of which brings us to a fascinating debate going on in the pages of the CDC’s EID Journal this month, in a series of letters under:
Body Lice, Yersinia pestis Orientalis, and Black Death
Welford M, Bossak B. Body lice, Yersinia pestis Orientalis, and Black Death [letter]. Emerg Infect Dis [serial on the Internet]. 2010 Oct [date cited]. http://www.cdc.gov/EID/content/16/10/1649.htm
DOI: 10.3201/eid1610.100683McLean RG, Fall MW. Body lice, Yersinia pestis Orientalis, and Black Death [letter]. Emerg Infect Dis [serial on the Internet]. 2010 Oct [date cited]. http://www.cdc.gov/EID/content/16/10/1649.htm
DOI: 10.3201/eid1610.100822Drancourt M, Raoult D. Body lice, Yersinia pestis Orientalis, and Black Death [letter]. Emerg Infect Dis [serial on the Internet]. 2010 Oct [date cited]. http://www.cdc.gov/EID/content/16/10/1649.htm
DOI: 10.3201/eid1610.100946
These are short, easy to follow letters debating this medical mystery and raise a lot of questions – some of which have public health implications today.
Although the debate isn’t settled here, if you like your science just a a tad on the messy side, you’ll want to read them.
Bubonic plague still occurs around the world, of course, although rarely in the United States.
This map, from the CDC, shows areas of the world where plague is endemic, mostly in rodents.
The last major urban outbreak of plague in the United States occurred in 1924-25 in Los Angeles. Since then, only scattered cases have been reported, with about 10-15 cases each year.
Worldwide, on average, anywhere between 1,000 and 3,000 cases are reported each year.
Today, modern antibiotics are very effective against the plague, and so outbreaks are usually quickly contained.
My interest in Plague stems from working as a paramedic in Phoenix, Arizona where plague cases are occasionally found, and my reading – at the tender age of 11 – of James Leasor’s The Plague and The Fire.
I’ve no doubt that this account of two incredible years in London’s history (1665-1666) - which began with the Great plague, and ended with the Fire of London – have unduly influenced my life, and interests, over the past 45 years.
Proving, I guess, that we should be careful what we read at an impressionable age.
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