Me, September 1, 2011:
Black Death not initiated by a plasmid? My money is on a moron.
Phages can encode for gene groups called morons.
I am not joking.
These are viral genes that dont code for anything the virus wants, like structural proteins, or enzymes the virus needs– They are genes that make having the virus around attractive to the bacteria. And few things are more attractive to a pathogen than making you sick, thus spread the bacteria faster than if you werent pooping/oozing/puking/etc.
I bet its a moron.
Nature, October 12, 2011:
A draft genome of Yersinia pestis from victims of the Black Death
Here we report a reconstructed ancient genome of Yersinia pestis at 30-fold average coverage from Black Death victims securely dated to episodes of pestilence-associated mortality in London, England, 1348-1350…Comparisons against modern genomes reveal no unique derived positions in the medieval organism, indicating that the perceived increased virulence of the disease during the Black Death may not have been due to bacterial phenotype. These findings support the notion that factors other than microbial genetics, such as environment, vector dynamics and host susceptibility, should be at the forefront of epidemiological discussions regarding emerging Y. pestis infections.
Welp. Shows what I know, dont it?
The bacteria that caused the Black Plague had no unique super scary plasmids. They had no unique super scary morons. They dont seem to have any unique super scary mutations.
The bacteria that ravaged the human population in Europe… is pretty much the same bacteria we can easily treat with tetracycline today.
I dont know about you, but this BLEW MY MIND.
A collision of *human* factors– human behaviors, human sociology, not enough food, no clue about sanitation or germ theory or quarantines, no antibiotics or medical advancements we view as ‘basic’ in the modern world, Europeans never being exposed to this kind of bacteria before…
There is no scary mutation one reversion away.
There is no reservoir of a scary plasmid or a scary moron lurking in the shadows, waiting to reemerge.
Turns out, what might have killed so many people during the Black Plague… was human ignorance and bad timing:
The Black Death is a seminal example of an emerging infection, traveling across Europe and claiming the lives of an estimated 30 million people in only 5 years, which is much faster than contemporary rates of bubonic or pneumonic plague infection and dissemination. Regardless, although no extant Y. pestis strain possesses the same genetic profile as our ancient organism, our data suggest that few changes in known virulence-associated genes have accrued in the organism’s 660 years of evolution as a human pathogen, further suggesting that its perceived increased virulence in history may not be due to novel fixed point mutations detectable via the analytical approach described here. At our current resolution, we posit that molecular changes in pathogens are but one component of a constellation of factors contributing to changing infectious disease prevalence and severity, where genetics of the host population, climate, vector dynamics, social conditions and synergistic interactions with concurrent diseases should be foremost in discussions of population susceptibility to infectious disease and host-pathogen relationships with reference to Y. pestis infections.
We cant lay all of the blame of The Plague on the bacteria. It wasnt just the bacteria. It was us, and old fashioned bad luck.