It never fails that I have a pile of big, important deadlines, and then POOF the most delicious pieces of science news land in my inbox. And I have to let them go.
And then I realized I have a NEWSLETTER! I may not be able to report the paper, but I can talk about it, and why it has me so excited.
So let’s go back. Back in time to ye olden days in the 14th century (well known in Good Omens as the century that Crowley hates the most). It’s the century dominated by the Black Death (1346 ish to 1353). Maybe that’s why Crowley hated it? Maybe it was the famine 1315 to 1317? Or maybe the Little Ice Age? The Hundred Years’ War? The Lollard movement? The antisemitic pogroms? The expansion of the Ottomans? I mean, Europe had a rough century is what I’m saying (Indonesia did, too. Also China. Heck Sudan had a time).
Maybe it was the leprosy?
Leprosy is a bacterial infection from Mycobacterium leprae, and has been a human disease for millennia. It’s nasty, and most known for causing lesions, like…losing a whole nose. It also causes nerve damage, blindness, it’s a rough disease. It’s not extremely transmissible, though it is contagious, and people knew contagious when they saw it. So infected people were isolated in leper colonies (the term of art is a “leprosarium”).
But leprosy not limited to humans. Bacteria aren’t picky. Many people who know about leprosy might immediately think of armadillos, which can carry leprosy, or even chimps. But now, think smaller. Think cuter.
Think squirrels.
(Captions are still giving me fits. It’s a red squirrel on a tree. Photo by Pearse O'Halloran on Unsplash)
It turns out modern red squirrels (Sciurus vulgaris) can actually carry leprosy too! And so a new study, published May 3 in Current Biology, looked at the city of Wincester in the 14th century. Because Wincester was a hot spot for squirrels.
Not for squirrel watching but for squirrel SKINNING. Red squirrels were popular pets, but they were also a very popular fashion statement. There are references throughout the Middle Ages and Renaissance of squirrel-lined dresses, hoods, cloaks, gloves. You name it, put a squirrel on it.
Most of these squirrels were imported, and many came through Wincester, where there was a big trade in fur. That means there were people, handling squirrel bits—and whatever those bits contained.
Some of those bits, it turned out, contained leprosy. The scientists analyzed 25 human and 12 squirrel samples from the period. They managed to isolate four genomes for the leprosy bacteria, and one was from a red squirrel. The genome was very close to one of the human strains.
The result showed that leprosy was moving back and forth between humans and squirrels in this period.
Why do I find this fascinating? Because we often see diseases moving from animals to people (cough, COVID, cough, or maybe H5N1) as a problem of modernity, a product of the way we farm, our huge populations pushing into wild areas, and on and on.
But people have always lived close to animals. Historical studies like this one are good reminders that animals, and their diseases, are all around us all the time, just like our fellow humans and THEIR diseases. Treat both with respect.
Citation
Urban et al. Ancient Mycobacterium leprae genome reveals medieval English red squirrels as animal leprosy host. Current Biology, May 3, 2024, DOI:https://doi.org/10.1016/j.cub.2024.04.006

Where have you been?
Is it reading about how an orangutan was spotted using a medicinal plant?! Every time we think we are special, we are wrong. By Darren Incorvaia.
Is it watching the latest Brain Scoop show on RATS?! Warning, dead rats.
Is it reading this very good newsletter by Charlie Jane Anders on peer pressure?
Maybe it’s buying PASTEURIZED MILK. Please. For the love of god. Pasteurization is one of the greatest public health advances of all time. Respect it. By Helen Branswell.
Maybe it’s reading this article on doomslang. The world is terrible, we’re all gonna die.
Maybe it’s reading this lovely feature on wildlife rehabbers in NYC by Benji Jones. Because in NYC, “wildlife” means pigeons, possums and squirrels.
Where have I been?
The wild part about freelancing is how I’ll put in piles of work for stuff I cannot talk about for MONTHS. But one has finally happened! As part of my freelancing, I’m a podcast writer, director, and producer. I got the wonderful opportunity to work with the National Academies of Science, Engineering, and Medicine on a podcast. The show gives real, actionable advice that companies can take to make their workplaces more inclusive and welcoming, particularly to women of color. And you can see the final result here!
Anti-Discourse Actions
I am done with Discourse, I am done with the endless seeking and reposting of misery to “witness.” Because witness does not help. Recent actions:
I’ve joined the Freelance Solidarity Project’s tracking program to track freelance pay rates! Freelancing rates are ridiculously un-transparent, and often really subjective. And really low. The first step to a living wage is data, and so I’m putting in my rates.
This is small, but I’ve begun the process of converting my entire back hill to native plants. It’s a real challenge, the soil is poor and COATED in ivy (half of it the poison variety). But I’ve begun and hope someday to promote all native plants for groundcover.
Letter writing season has begun! We are sending handwritten letters (via Vote Forward) to encourage people to vote. We do not tell people who to vote for, or against. We only encourage them to exercise their right.