David Reich

And in 5% to 10% of the random people they sequenced around 4,000 or 5,000 years ago, there was Yersinia pestis, which is the agent of the Black Death.

But actually, without the

without the plasmid that contributes to bubonic plague that's required for flea rat transmission.

So it must have been, for example, pneumonic plague with the aerosolized transmission or something.

But five to 10% of random deaths means that actually the percent of people who were dying must have been even higher.

higher because they weren't detecting everything that was there.

A study by another group, Johannes Krauss and colleagues, of people in plague pits in London from the 1300s epidemic found that when you apply this method to people we know died of Black Death, you only find a quarter of the people, so the rate was even higher.

If people are bacteremic when they die, if they have bacteria in their teeth, they probably or almost certainly died of that agent.

So a paper just came out a few weeks ago in Scandinavia looking at these tombs from about 5,000 years ago of farmers who were just on the verge of encountering people from the steppe.

And a huge fraction of them have black death when they die.

They're buried in tombs and normal, even higher than 5% or 10%.

So this whole pedigree with many, many generations, so it's not all at the same time.

Just like the parents, generation to generations, a very large fraction, like well more than 10%, have black death and have Yersinia infection.

So it looks like this particular agent has been killing...

people for 5,000 years, four or 5,000 years in Western Eurasia, and in fact is killing, like, a scarily large fraction of the population.

Like, as a quantitative person, which I am reading this literature, I think people are embarrassed by the implication.

The implication is that

a third, a quarter, a half of deaths in this entire period are from this.

It's so unbelievable, so ridiculous that such a high proportion of people over such a long period of time are dying from this one agent that people don't even say it.

They just publish one paper after the other, publishing more sequences, and they just don't think about the implications of such a high rate of death.