What is a virus? Is it even alive?

How to explain to young kids what is going on, what is disrupting their lives.

This is really bad. The Covid-19 pandemic is shutting everything down. In Germany all schools are closed, homeschooling is part of the daily agenda.

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The kids get daily lessons from their teachers via the Internet, they send their homework back by email. They are getting on well, but sorely miss school and playing around with their friends. They are social animals. Enders is writing a Journal of the Corona Year. It emulates something Daniel Defoe did for Yersenia pestis a number of centuries ago.

One question the boys had was: what is corona, what is a virus? I explained it with the following analogy, which you are welcome to use on your kids:

Imagine you are out on a walk, and a hippopotamus follows you back home. It starts to multiply, and soon your garden is full of these animals, which are destroying everything. So you must do something about them. Luckily you have a gun, and can kill them all. The hippos are bacteria, the gun is an “antibiotic.” The ability to quickly kill bacteria changed the world.

Now imagine on the walk you find a sheet of paper, which you pick up and take home with you. On it you read: “Make photocopies and throw them out on the street,” which you dutifully start to do. Until your mum and dad see it and tell you to stop.

That’s how a virus works. It tells the cells in your body to make copies, which they do, until antibodies stop them. The difference in size between a hippopotamus and a sheet of paper is approximate the difference in size between a bacterium and a virus. Okay, I greatly exaggerated — a virus is maybe a hundredth the size of normal bacteria. A bulldog or a wild boar following you back home would be more realistic, but kids find the idea of hippos in your garden more amusing. It makes a point that will stick in the heads of the kids.

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Bacteria come in different shapes and sizes — show your kids a funny picture of microbes, like this one from Freepik. But also do an image search on google to show them what real bacteria look like. Also tell them that there are plenty of good bacteria. The human body is full of them. How many? Hennes guessed around a thousand.

No, Hennes, it is closer to 30 trillion, almost the same number as body cells (40 trillion). We couldn’t live without them.

Most good bacteria are in the large and small intestine. They help us digest food and generally keep us alive and well. So they are very useful. But there are also bad bacteria that invade the body and make us sick, even kill us. For thousands of years people did not know this — bacteria are too small to see with the naked eye. People thought illnesses were due to sinful behaviour, the wrath of the creator of the universe, evil spirits, evil eyes, malicious individuals poisoning wells, or simply “bad air.” In the early 18th century physicians thought a deadly fever disease was caused by foul air in marshy districts, and a Roman doctor named it mal aria (Italian for bad air). Much later scientists discovered that it was tiny microbes that were transmitted by mosquitoes. You can read my story, “On the eighth day God created mosquitoes” on that.

Pathogenic bacteria can be devastating: in medieval times one particular variety periodically decimated the population — of the world! Bubonic plague, or the Black Death, as it was known, killed more than 50 million people worldwide, including over a third of the entire population of Europe in the 14th century. No cause (rats, fleas), no cures were known at the time. Today plague can still occur in Congo, Madagascar and Peru — and in California. I believed I had contracted it there, but it was a false alarm. In any case plague is highly responsive to antibiotic therapy and causes just a handful of deaths each year — when victims failed to reach a doctor.

Bacteria are living creatures that feed, grow and multiply. A virus is basically just a set of genetic instructions, DNA or RNA molecules, to build new viruses, which it cannot do by itself. The ones that cause immediate or imminent death cannot spread — carriers are not around to mingle with other people. Viruses that produce mild symptoms, at least initially, can be highly contagious, since infected people will move around, happily spreading them to anyone they meet. That is what the new coronavirus is doing.

Incidentally, some terminological clarification is needed. Coronaviruses are a family of hundreds of viruses, which generally cause respiratory problems and fever. The one that has currently brought the world to a standstill is called SARS-CoV-2, = the second major Severe Acute Respiratory Syndrome coronavirus (the first, CoV-1, went pandemic in 2003 and was popularly referred to simply as SARS). The current disease is properly called Covid-19, which is short for Corona virus disease 2019. If someone says “500 people were infected by the coronavirus,” ask “Which one?”

And remember: viruses are not “alive” in any normal sense of the word. They may have some vague purpose in nature, but at the same time can inflict horrific misery on the innocent. So why do they exist? For the same reason there are earthquakes, tsunamis, asteroid impacts and other calamities that befall the inhabitants of the world. The reason all these horrible and deadly things happen is simply: because it is possible. I repeat: Because. It. Is. Possible. No other reason. No divine plan, no need to look for the wrath or revenge of an invisible being, to look for a purpose in nature. Evolution has created mosquitoes and deadly viruses, and physics produces earthquakes and tsunamis. Simply because it is possible.

Written by

Frederic Alois Friedel, born in 1945, science journalist, co-founder of ChessBase, studied Philosophy and Linguistics at the University of Hamburg and Oxford.

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