During the 14th and 15th centuries the Black Death killed more than 75 million people
throughout Asia and Europe. The
vast spread of the Black Death was caused by a highly contagious strain carried
by fleas and rats. However this week in London, Archeologists have found evidence
that suggests a different reason for the quickness of its transmission,
airborne infection.
Last year, twenty-five
skeletons were dug up from a burial ground in the Clerkenwell London area. After
examining the teeth of each skeleton, forensic specialists found Yersinia Pestis, the DNA of the black plague. When scientists compared this strain to
one that had recently killed sixty people
in Madagascar, they found that the 14th
century strain was no more virulent than today’s strain. In better terms, the
DNA from the skeleton strains was almost an exact match to those strains in
Madagascar. It is likely that all twenty-five skeletons who were exposed to the Black Death, died from it.
According
to scientists at Public Health England in Porton Down, the only way for the
plague to have spread so quickly and over such a large range was for it to have
gotten into the victim’s lungs. By being transmitted through coughs and sneezes
rather than rats, the Black Death would actually be a pneumonic plague rather
than a bubonic plague. The rate of transmission from household was so fast,
that there is now way a rat or flea could be result in the high number of
plague cases.
With the
help of modern day antibiotics, scientists can prevent the disease from
becoming pneumonic. However, those who do not have access to these medications
can still die from the disease.
Posted by: Lindsey Janof (8)
This was a very interesting topic to bring back. We learned in history class back in middle and high school that the Black Death was caused by rats. The fact that the black plague is caused by a virus that gets into the victim's lungs is more terrifying to me than if it were to be caused by rats. Airborne infections are a lot easier to transfer from person to person compared to other infections. Do you know how long it takes an infected person to show pneumonic symptoms?
ReplyDelete-Amber Vien
I believe that patients showing pneumonic symptoms would be almost the same as those showing bubonic symptoms. The only difference between the two would be the transmission of the disease. From the studies above, scientists have concluded that the rate of transmission was too high to be only bubonic, thus making pnuemonic transmission more likely to be the cause.
DeletePosted by: Lindsey Janof
I would imagine that the plague was spread by both air borne mechanisms and by the fleas on rats. There was previously a lot of evidence to support this theory, and only recently has evidence come out to suggest that the disease was air borne. Do you know if cases of the plague in modern days have been studied to see if they can be spread via the air? I also wonder what the term would be for a mix between bubonic and pneumonic.
ReplyDeletePosted by Tim Daly
Viruses of this scale and deadliness are always very interesting topics. Diseases such as this can evolve and spread so fast it is hard to keep up with them. Do you think that the plague could have evolved or mutated from a bubonic plague to a bubonic and pneumonic plague?
ReplyDeleteFrom the data above, we can see that the strain for the Black Death during the 14th century is almost exactly the same as the one that killed sixty people in Madagascar. So, the strain hasn't really evolved since the epidemic. However, I definitely think that it was a mix of both bubonic and pneumonic exposure that caused this disease to become so widespread.
DeletePosted by: Lindsey Janof