Black death was not spread by rat fleas, say researchers


"Archaeologists and forensic scientists who have examined 25 skeletons unearthed in the Clerkenwell area of London a year ago believe they have uncovered the truth about the nature of the Black Death that ravaged Britain and Europe in the mid-14th century.

Analysis of the bodies and of wills registered in London at the time has cast doubt on “facts” that every schoolchild has learned for decades: that the epidemic was caused by a highly contagious strain spread by the fleas on rats.

Now evidence taken from the human remains found in Charterhouse Square, to the north of the City of London, during excavations carried out as part of the construction of the Crossrail train line, have suggested a different cause: only an airborne infection could have spread so fast and killed so quickly…"

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Black death was not spread by rat fleas, say researchers


This makes sense to me. I’ve occasionally wondered, in an idle moment, how so many people could have fleas at the same time. Rats and fleas might be vectors, but an airborne contagion makes a lot more sense if we consider whole families were wiped out overnight.

One also wonders if the rats were in plague proportions due to the numbers of dead bodies. Which came first - the rats or the plague?


Several years ago, I visited the Badlands of South Dakota.
There were signs up warning that the prairie dogs were infected with bubonic plague.
And sure enough, I saw some of them.
Not a pretty sight.
Fortunately, I was in the car with all the windows rolled up.


Interesting report but I still think bubonic plague spread by rats is still the most likely culprit. Back in those days after the fall of the Roman Empire, people lived in filth so its very plausible that fleas can spread this very rapidly. If anyone has owned a lot of pets you’ll know that if one pet gets fleas all of them will have it pretty soon.


Don’t forget that back then it was common to keep livestock in houses. And houses weren’t what they are now. Even the wealthy would have serious issues with rats and fleas.

In regards to ground squirrels today, almost everywhere they live, the plague is found. It’s our proximity to them, general cleanliness, and modern healthcare that keep it at bay. People still get it. And it’s not airborne. Diseases do not devolve that we know of.


Pneumonic plague and Bubonic plague are caused by the same bacteria. When bubonic plague is untreated, there is a chance that the bacteria will infect the lungs to a degree that the bacteria can be spread when the patient coughs or breathes out, i.e. become pneumonic.

You will not see pneumonic plague without an underlying epidemic of bubonic plague.

The speculation that pneumonic plague was involved in the Black Death has been around for many years. It makes sense that PP might develop in conditions in which people infected with bubonic plague are living in close quarters to healthy people. A medieval city such as London would be a prime environment, especially during the cold months when people spend more time indoors.


From a conspiracy theory angle it sounds like “research” news designed to prep the public for the next epidemic scare. A disease spread by rats would not be believable in the first world nowadays. Hey, what about one spread by birds? That didn’t pan out. There were county vaccine centers set up and long lines, but the majority of the public did not buy into the bird flu scare.


“That’s NEW?” was my first reaction to this story.

While I’m sure fleas weren’t in short supply at the time, it seems likely that in the unsanitary conditions in existence pneumonic plague would have developed in a fairly high percentage of the bubonic patients. It would then have spread like wildfire to the rest of the population.

Isn’t that a fear of the CDC? That one or more of the cases of bubonic plague in the US each year will fail to be treated promptly and progress to pneumonic and then endanger a large sector of the population?

I read a novel several years ago whose premise just that. A teenager who’d gone camping and come into contact with an infected animal (squirrel? gopher?) returned home to an empty apartment where he became seriously ill. His bubonic plague progressed to pneumonic and he proceeded to infect a busload of people as he travelled through the city to the hospital resulting in a citywide epidemic.


A little off topic, but I recall reading that there is a church in Italy named “Santa Maria Della Salute” (Our Lady of Good Health). It was built as part of a promise made by the citizens of the city that they would built it if Our Lady would lift the plague there.

For some reason that I don’t know, a very significant explosion in the cat population happened as they were building the church, and many of the cats took up residence in the church as it was being constructed. Perhaps predictably, the cat explosion appears to have led to a decimation of rodents and a lifting of the plague. Apparently the citizens associated the cat proliferation with the plague’s disappearance. Whether they knew what the connection was is uncertain.

I understand the builders put in lots of little shelters within the structure so cats would have places to get in out of inclement weather. The cats there are given a daily ration of pasta to this very day. (apparently cats like pasta)

The church is also locally called “Our Lady of the Cats”.


Yes, this is old news …
seems to me that some folks try to re-write the history books.
Those black rats got on your ships too Britania and caused bubonic plague via a bacteria called Yersinia pestis which then became air-born causing pneumonic plague and even a third variety of plague:

[quote]Human Y. pestis infection takes three main forms: pneumonic, septicemic, and bubonic plagues.[1] All three forms were responsible for a number of high-mortality epidemics throughout human history,




There is, I understand, a theory held by some that while rats played a role, part of the problem was a significant dietary deficiency due to poor harvests for some while.


This occurred during the “Little Ice Age” and immune systems would have been low due to the poor harvests you mention. Plague is a nasty disease, but an unhealthy person will fall more quickly to any illness.


From the CDC website:

There has been at least one case of plague in humans in the US a year for the last 42 years. ~40 cases in 1983 alone. 80% of those were bubonic plague. Mostly caused by exposure to rodents in the wild (rock squirrels, wood rats, ground squirrels, prairie dogs, chipmunks, mice, voles, and rabbits) either through the fleas they carry or by exposure to their contaminated body fluids or tissues (i.e. the hunter who skins an infected rabbit).

There hasn’t been a case of human plague caused by droplet infection in the US since 1925.


Let’s hear a round of applause for cats! :clapping::clapping::clapping:

Hmmmmm. I guess in the southwest, we owe one to rattlesnakes too, don’t we? :o


And owls, hawks, coyotes, etc…


I think you owe it as much to the doctors who recognize and treat the cases of bubonic plague before they become pneumonic plague and spread like, well, the plague.


It is said that one medicinal use of garlic is as an antibiotic, and that monks used to soak crushed garlic cloves in vinegar, then soak a cloth in the mix, and tie the cloth over their nose and mouth while ministering to those sick with bubonic plague, and in this way they were spared.


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