an autodidact meets a dilettante…

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Archive for the ‘coronavirus’ Category

2019-nCoV: where does it come from?

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whether or not they led to 2019-nCoV in humans, leave pangolins alone

As mentioned previously, there are lots of coronaviruses. The four most commonly found in humans have these memorable names: 229E, NL63, OC43 and HKU1. These are humanly-borne viruses that seem to be more interested in increasing spread than increasing pathogenicity. We seem to have developed enough of an immunity from these common coronaviruses for them not to be a major problem. It’s perhaps the new strains that jump from bats to humans via an intermediate species – civets in the case of SARS, dromedary camels (probably) in the case of MERS – that are most likely to be pathogenic. Researchers are on the hunt for the intermediate carrier in the case of 2019-nCoV. Snakes were first suggested, but this has now been dismissed. The most recent candidate has been the pangolin, after research from the South China Agricultural University on the genome sequences of pangolin viruses found them to be 99 percent identical to those in coronavirus patients, but this is unpublished, unverified data at present.

Civets, pangolins? These are just some of the more or less exotic wild animals that some Chinese people like to consume or use for ‘medicinal’ purposes. Traditional Chinese medicine, aka medicine that doesn’t work, has a lot to answer for. Health experts are now recommending that the Chinese government clamp down on this practice. The presence of these creatures in open Chinese markets is disturbing. A prohibition was apparently put in place by the Chinese government just last month, a matter of shutting the stable door, but how well this will be enforced is a question.

Civet – harmless purveyor of SARS, and forget the coffee hype

Over the past 24 hours I’ve been coughing up a storm, and I’m due to work tomorrow. Medications are reducing the inflammation, and I note that wearing a common or garden surgical mask, which we see everywhere now, will not help. To quote from Live Science:

Coronaviruses can be transmitted between humans through respiratory droplets that infected people expel when they breathe, cough or sneeze. A typical surgical mask cannot block out the viral particles contained in these droplets, but simple measures — such as washing your hands, disinfecting frequently touched surfaces and objects, and avoiding touching your face, eyes and mouth — can greatly lower your risk of infection.

Of course I don’t have such a virus, and there are no known cases of it in Australia, though at least five Australians on a cruise ship off Japan have been confirmed as having contracted it. But as to surgical masks, the point is that viruses are much smaller than bacteria (on average about 1000 times smaller). They’re not cells, with their full complement of DNA, but strands of nucleic acid (DNA or RNA) encased within protein. They’re parasitic on hosts, unlike bacteria, and they’re generally pathogenic – we don’t have ‘good’ viruses as we have good bacteria. They can live outside of hosts for a limited period of time – hence the need for hand-washing and general cleanliness. Viruses in general may take a variety of shapes and sizes, ranging from the recently-identified DNA-based pandoraviruses at 1000 or so nanometres (1 micrometer) down to 20 nanometres or less. As to coronaviruses in particular (the largest of the RNA viruses) their structure and their ‘spike proteins’ will be glanced at in the next post.

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457962/

https://www.thoughtco.com/differences-between-bacteria-and-viruses-4070311

https://www.sciencealert.com/the-pangolin-is-now-a-suspect-in-the-coronavirus-outbreak

https://www.livescience.com/face-mask-new-coronavirus.html

Written by stewart henderson

February 9, 2020 at 12:27 pm

coronavirus – a journey begins

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this is an electron micrograph of 2019-nCoV – ref JOHN NICHOLLS, LEO POON AND MALIK PEIRIS/THE UNIVERSITY OF HONG KONG. The cell is infected with the virus (the little black dots), which migrates to the cell surface and is released

Lots of information and disinformation around the recent outbreak of coronavirus, and my own occasional workplace, a college that teaches academic English to overseas, predominantly Chinese students, is naturally affected by the precautionary procedures and the possibly OTT concern.

This is a new strain of coronavirus, first detected late in 2019. It hasn’t been given a specific name, as far as I’m aware (apart from 2019-nCoV,  which I doubt will catch on) so lay people tend to think this is the one and only coronavirus, since most have never heard the term before. These viruses are zoonotic, transmitted between animals, from bats to humans. My interest is most personal, because when I read that the signs are ‘respiratory symptoms, fever, cough, shortness of breath and breathing difficulties’, I recognise my life over the past several years. I wouldn’t go as far as to say I have a fever, but all the other signs are just features of my life I’ve become inured to over time. I’m reluctant to even talk to people lest my voice catch in my throat and I have to give myself up to hideous throat-clearing, which I do scores of times a day. I’m also afraid to get too close as I assume my breath smells like rotten meat. I should probably wear a face mask at all times (hard to get one for love or money at this point). My condition has been diagnosed as bronchiectasis, possibly contracted in childhood, but I’m fairly sure it was exacerbated by a very severe bout of gastro-enteritis in the late eighties, which left me bed-ridden for several days, too weak to even get to the toilet. When I eventually recovered enough to drag myself to the doctor, she arranged for me to go to the hospital next door for blood tests. It was unspoken but obvious to me she thought I might have AIDS, which I knew was impossible given my non-existent sex life and drug habits. It seems to me, but I might be wrong, that my life of coughing, sniffling and raucus throat-clearing took off from that time.

All this by way of explaining why these types of illness catch my attention. WHO advice is for people to, inter alia, wash hands regularly, cook meat and eggs thoroughly, and keep clear of coughy-wheezy-sneezy people like me. 

Coronaviruses are RNA viruses with a long genome, longer than any other RNA virus. According to Sciencealert they’re so called because of the crown-shaped set of sugar-proteins ‘that projects from the envelope surrounding the particle’. This one is causing perhaps a larger panic than is warranted, when you compare its fatalities (and the numbers should be treated with skepticism at this stage) with those associated with regular flu season. Of course, the difference is that this coronavirus is largely unknown, in comparison to seasonal flu, and fear and wariness of the unknown is something naturally ‘programmed’ into us by evolution.  

There’s an awful lot to be said about this topic, biochemically, so I’ll write a number of posts about it. It’s not only of great interest to me personally, but of course it fits with my recent writings on DNA and its relations, including RNA of course, and to a lesser extent epigenetics. I’m becoming increasingly fascinated by biochemistry so it should be an enjoyable, informative journey – for me at least.

References

Cases of the new coronavirus hint at the disease’s severity, symptoms and spread

Updated: Your most urgent questions about the new coronavirus

https://www.who.int/health-topics/coronavirus

Written by stewart henderson

February 8, 2020 at 10:57 am

Posted in coronavirus, health, RNA, viruses

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