In this week’s Sunday Science: some facts on the new coronavirus that is spreading through China (and abroad); how stress turns your hair grey; how scientists are stressed (so we’ll all go grey early); how human body temperatures are falling, and growing your own snake venom….

The big science story of the moment is, of course the spread of the worrying new coronavirus, which causes flu-like symptoms, across China and now with cases confirmed in other countries including the US and France. There’s a good summary in the Guardian here, with a podcast here by a virologist and an epidemiologist. The premier science publication Nature has produced its own little video guide here:

China has responded strongly, with a lockdown of the entirety of Wuhan province – at least in part because it was criticised over its sluggish reaction to the SARS outbreak of 2002, which resulted in around 8000 infections and nearly 800 deaths.

How dangerous is it really? This coronavirus appears – so far – to be less dangerous, but the epidemic is still very early. The estimated mortality rate at the moment is 3% (compared to 9.6% for SARS) but is actually likely to be lower due to mild cases not being identified. Like seasonal flu (mortality rate 1%) it appears most dangerous to the elderly and weak. Human to human transmission appears to be occurring, but how easily this is happening is still a question. There have also been some quite hysterical social media threads about the R value – this is how transmissible it is to other people. For one thing, we only have estimates of these because it’s so new. Here’s a recent one (incidentally, @maiamajumber on Twitter is a good one to follow for updates). For another, about 5% of unvaccinated people who get measles end up in hospital with pneumonia and it has a mortality rate of around 0.3% and a truly high R value of 12-18 (source: WHO), and there’s fools out there freaking out over coronavirus who won’t use the perfectly safe measles vaccine! Oh, and the new coronavirus most likely did not come from snakes, as some excitable news outlets have suggested (also see here). Your best advice to protect yourself from pneumonia, per se, would be to practice rigorous handwashing and to get the seasonal flu vaccine, if you have not already done so.

Confirming something most of us probably suspected, stress really does make your hair turn grey more quickly.  What’s interesting is how and why this happens: it’s not down to immune attack on the pigment-producing cells, or due to the long-term stress hormone cortisol. It is in fact down to noradrenaline (related to adrenaline), released in the fight-or-flight response. A new study (featuring some poor stressed mice, I have to say) has shown that nerves releasing this hormone extend into the hair follicles, and stimulate the stem cell pool to differentiate into melanocytes, pigment-producing cells, in large numbers. But then those extra cells drift away and break down. Next time you need to make more pigment cells, the stem cell pool is depleted, and once it’s gone, it’s gone, so you can only make grey hair after that. The study has implications not just for vanity but for the normal aging process. Full study published in Nature here.

Speaking of stress: who’d be a scientist?A global study suggests that the profession is ripe with stressful working conditions, bullying and harrassment, and an unpleasant working environment and job insecurity generated by the intense competition to publish results and gain funding. It only confirms what many scientists have been saying for a long time – the culture needs to change, and the whole way we do science needs to change to deal with problems like this, but also problems with poorly reproducible data.

A rather curious finding here: human body temperatures are falling.We’re all taught that the “standard” human body temperature is 37C, which the body maintains very rigorously; it rises by a degree or two when we have a fever in response to an infection. It seems like mean (average) human body temperature has fallen by about 0.03°C per birth decade since this 37C was proposed as standard in 1868. Why? It could be due to slightly slower metabolisms, or that, at least in fairly affluent populations, we get far fewer infections than we used to. Study published in the journal eLife here.

And finally, time for something really cool: snake stem cells have been used to grow organoids (simplifed mini organs grown in culture) that can produce venom. Researchers took stem cells from the venom glands of the Cape coral snake (featured image), and cultured them into little mini gland organoids that could make the venom. It’s an impressive piece of work on a non-model organism for which no standard techniques or published genome exist. OK, so it just sounds like something an evil Bond supervillain might do, making their own supply of snake venom on tap, but there’s a serious purpose. Poisonous snake bites kill around 100,000 people a year, so this work could potentially be really useful for providing a source of venom to test treatments. Additionally, biologically active compounds in animal and plant toxins are a rich and still largely unexplored treasure trove of potential future medicinal drugs; this allows detailed study without having to harvest venom and glands from lots of live (or dead) animals. Original study published in Cell here.

Featured image

Cape Coral Snake, Aspidelaps lubricus. One of the species used in the snake organoids study. Credit: Ryanvanhuyssteen [CC BY-SA (

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