Researchers: Rats Didn't Spread Black Death, Humans Did 135
concertina226 (2447056) writes "Scientists studying the human remains of plague victims found during excavations for London's new Crossrail train line have concluded that humans spread the Black Death rather than rats, a fact that could rewrite history books. University of Keele scientists, working together with Crossrail's lead archaeologist Jay Carver and osteologists from the Museum of London, analyzed the bones and teeth of 25 skeletons dug up by Crossrail. They found DNA of Yersinia pestis, which is responsible for the Black Death, on the teeth of some of the victims."
Re:actually, it was the fleas. (Score:5, Interesting)
Well, the Norway (aka "brown") rats are carriers of an almost incredible variety of infectious agents that are human pathogens, including hantavirus and Toxoplasma.
The issue with rats isn't that they're *particularly* susceptible to zoonotic pathogens. The issue is that they're well adapted to living around human habitations,which provide them with excellent protection from predation. With plenty food and shelter and no predators, they reach unnaturally high population concentrations. These populations are "preyed upon" by germs instead of carnivores, because inevitably everything in nature is food for something else. Some of those pathogens will also effect humans, and since those dense colonies are living in close proximity to dense colonies of *humans*, brown rats present a public health concern, even though none of their pathogens have quite the marquee name recognition of The Black Death.
Another example of this phenomenon is the raccoon. Because raccoons are still frequently encountered in natural settings people don't have the same revulsion towards them as they do towards rats, but raccoons are just as well adapted to living with humans as rats are. In places where high raccoon populations live in close proximity to humans, they're a serious health concern. I've known natural science geeks -- people who have no qualms about handing dead animals or picking through animal scat -- to treat suburban raccoons with revulsion. A suburban raccoon can be a terrifying bag of disease, and there are documented cases of people dying as a result of handling their poop.
It doesn't mean racoons are *bad*, or that rats are *bad*. It means that wild animal populations with nearly unlimited resources and no predation are an all-you-can-eat banquet for germs.