One of the most exciting things about science is correlation. Correlation in science is the nerdiest of nerd heaven, the a-ha moment, the stuff that makes your logical brain loop around in bliss. Wanna hear about the a-ha moment in the immunology talk the other night? It’s a good one.
Humans share their evolution with parasitic worms. Yeah, that’s not quite it. Animals have always been riddled with parasites – whether it’s symbiotic, commensal, parasitic or downright predatory. Flesh is for the taking. In our own evolution, parasites have been with us, side-by-side from the very beginning. Roundworms, tapeworms, whipworms – we’ve been like a worm festival. Until recently, when some of us haven’t anymore. In the last century, a lot of humans got de-wormed. Literally. Anti-worming medication was at the forefront of pharmaceutical development.
My sister-in-law was a kid the decade before I was. She often recounts their regular de-worming as children. I’d wrinkle my nose when she talked about it. They were regularly de-wormed? We were never de-wormed, not that I knew of anyhow. And I’m pretty sure if we were, no one would have been shy to tell us. So was that when things changed – from needing to be exhumed of parasites in the 1960s to not needing it anymore in the 70s onwards?
I’m not sure. Timescale aside, de-worming in the UK is definitely relatively scarce now. Overall, people don’t have intestinal, parasitic worms in the developed world any more. If I told my kids about worms in our guts they’d wrinkle their noses – especially if they complained their asses were itchy.
‘Could it be worms?’ I’d ask.
‘WTF! Worms? Like the ones you see in the soil?’
They know a lot about auto-immune disease though. Rheumatoid arthritis, inflammatory bowel disease and lupus – made recently notable by Selena Gomez going public with having the disease. They know about allergies too, and eczema and asthma. All of these inflammatory conditions where the body turns on itself in one form or another.
Professor Sheena Cruickshank blew us away at her talk on Thursday night. Besides showing us that 3D clip of whipworms burrowing into human gut. She obviously put a lot of sales appeal into the clip and gave everyone funky, retro 3D glasses to watch it, but that bit wasn’t really that good. Hollywood would have passed. No, the bit that blew our brains off in the end was a simple, 2D colour-coded global map of the incidence of worms still prevalent in developed versus developing countries.
The map was as you’d expect – parasitic worms still being significant in humans in developing countries compared to a relatively low incidence in developed ones: Europe, North America – places where national de-worming campaigns have been strong for years.
Another map came up on the screen. The map showed an opposite pattern. This time the colours were focused on countries where there was a high incidence of auto-immune disease. These were the same countries with also very little incidence of worm infestation. As Prof Cruickshank put it, an inverse correlation.
Jaws dropped in the room. Is there a relationship between the lack of worms in our bodies and our immune system attacking our own body? Prof Cruickshank wasn’t going to commit for sure – to do so would be against the evidence-based, hypothesis-driven gold standard of the Royal Institution. It was ok though. We’d already had the a-ha geeky rush that made us fall in love with science all over again.
Does the immune system get bored if it doesn’t have worms to attack? Is it like a bored teenager with too much time on its hands? Can you imagine if it had Snapchat or Insta to fill its time with? The suggestion is that instead it goes rogue.
Prof Cruickshank explained that when people move from the developing to developed countries the trend they see is lose the worms and… get allergies. These two things tend to go hand in hand. The solution, she suggested, may be to grow and introduce a sort of sterile, non-destructive worm back into our gut. Before we could all shake our heads at the audacity of the suggestion, she reported it’s already being done. Give the immune system something to do, something it’s been programmed for since the beginning. The things correlation persuades us to do.