It seems that not only did rats get an undeservedly bad rap for the Black Death, but that the evidence favors a very simple explanation for its deadliness. Researchers have determined that the plague that wiped out 60% of London’s population in the 14th century was pneumonic — meaning spread through the air — rather than bubonic:

On Sunday, London scientists who’d studied 25 skeletons discovered in a new rail line said everything we’d thought about the bubonic plague — what caused it, what kind of disease it was, its strength — was wrong. Most of the ensuing coverage focused on the finding that the disease wasn’t likely spread by rats’ fleas, as has been taught in every high school in the West, but had actually been airborne.

But that discovery overshadowed a bunch of other equally fascinating findings, which provided a glimpse into how Europeans lived during the darkest chapter in human history.

And the article goes on to describe how horribly Europeans lived at that time.

It’s not clear if people are grasping the full meaning of this. The exact same strain of the plague that wiped out millions upon millions of people in a relatively short time surfaced in Madagascar last year and only managed to kill 60 people. What’s the difference between now and then? Most people living in London in the 14th century had horrible lifestyles — they were dirty, malnourished, got into a lot of fights, and were probably working under brutal conditions. When a person’s overall lifestyle is poor, that makes him much more susceptible to deadly disease. It’s the same principle that explains why some people with HIV go on to get devastating diseases like AIDS and some don’t. Adopting a very restrictive and healthy lifestyle is the best protection a person has against not only infectious disease, but against functional disorders like neuroses, cancer, adult-onset diabetes, and so on.

We’ll be writing a lot more about this topic in the future and how it relates to a meta-principle that turns out to vindicate Christian philosophy in a most powerful way.