What Virus causes the disease COVID-19?

SARS-CoV-2 is the virus that causes Covid-19. A virus is genetic material contained within an organic particle that invades living cells and uses their host’s metabolic processes to produce a new generation of viral particles. What Virus causes the disease COVID-19? Coronavirus, Novel Coronavirus, SARS-CoV-2, Covid-19 What are the definitions?

How big are viruses?

The size of a single human hair is comparable to the size of as little as 400 SARS-CoV-2 particles to as many as 1,000 particles.

Virus sizes vary from the extremely minuscule – 17 nanometre wide Porcine Circovirus, for example – to monsters that challenge the very definition of ‘virus’, such as the 2.3 micrometer Tupanvirus.

How much smaller are most viruses in comparison to bacteria? Much smaller. With a diameter of 220 nanometers, the measles virus is about 8 times smaller than E.coli bacteria

Are viruses living or not?

For about 100 years, the scientific community has repeatedly changed its collective mind over what viruses are.

First seen as poisons, then as life-forms, then biological chemicals. Viruses today are thought of as being in a gray area between living and nonliving. They cannot replicate on their own, but can do so in truly living cells and can also affect the behavior of their hosts profoundly.

Some say it’s more accurate to think of viruses as part of the continuum between chemistry and biology, one that isn’t clearly divided into living and non-living.


When could we first see viruses?
Electron microscopes were invented in the 1930s. For the first time, we could see what viruses looked like, such as the H1N1 virus that caused the 1918 Spanish flu.

Where did the word virus come from?
The word virus comes from a Latin word describing poisonous liquids. This is because early forms of isolating and imaging microbes couldn’t capture such tiny particles.

Resources, including good Covid short videos

Good article – well written and easy to understand, plus more related articles.
What’s a virus, anyway? Part 1: The bare-bones basics

Video animations

You can’t really “see” the virus, but animations can really help understanding them.

How Coronaviruses Work – Good overall view from Johns Hopkins

More technical, but understandable, from Scripps Research

Coronavirus Anatomy Explained: Science, Simplified

How the Novel Coronavirus Infects a Cell: Science, Simplified

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