This week you may have seen stories from news sites like this one touting "new findings" about the Black Death, suggesting that it was not a bubonic plague spread by fleas on rats, but a pneumonic one spread via human coughing. Almost all these stories are sourced from this Guardian piece, and they're all misleading or just plain wrong, writes Brooke Borel at Popular Science. That's because the Guardian's revelations spring not from a new peer-reviewed study, but from hype for a BBC documentary.
The prevailing theory is that the Black Death was caused by plague, aka Yersina pestis. The disease has three forms:
- Bubonic: Manifests in the lymph nodes in the armpits, neck, and groin; transmitted when a flea from an infected rat bites you.
- Pneumonic: Infects the lungs; transmitted when an infected person coughs or sneezes on you.
- Septicemic: Occurs when the infection hits the blood, causes gangrene on the hands, feet, lips, and nose.
Experts are pretty sure—and have been for a while—that all three were evident during the Black Death. Unless rats were coughing into people's faces, the plague must have been bubonic at some point. From there, victims may have developed secondary pneumonic infections, and passed them to others via coughing. Tim Brooks, who is quoted in the Guardian
article, says the suggestion that the plague was entirely pneumonic is "an interesting and entirely erroneous interpretation of anything I said!" (These other recent Black Death revelations
, however, still hold.)