Viruses in a Nutshell
Hm,… How to explain viruses for kids?
OK, let’s start with the following:
They are tiny and lonesome
Viruses are very, very small even compared to bacteria. How much smaller are they compared to bacteria? Do you remember what I told you about the average size of bacteria? Now, usually, a virus is even 10 to 100 times smaller than the average bacterium.
Hello again! Hi there, big guy!
Consequently, while you can see bacteria under a microscope, you definitely will need an electron microscope to see a virus.
Also, viruses always come as single units. A virus can often multiply very fast. But, however large their numbers, they never form multi-unit entities. Adding to that they do not interact with each other, such as bacteria sometimes do.
It is not certain if viruses are alive
Yes, you have read correctly. An important difference from all other life forms on our planet is that viruses are not able to live, reproduce and multiply by themselves. They also never eat food or absorb sunlight (like plants do) or use other energy sources. These little critters are not able to produce any products that are useful to themselves or us. They don’t move. If you saw a virus lying in the street (imagine how tiny you would have to be for that), you would probably think that it is dead, or even just some weird modern art object.
It isn’t doing ANYTHING. Consequently, even scientists argue whether a virus can be called life or not.
However, when they infect a cell….
Viruses need help to survive and multiply
Viruses will always need a living host cell, which they infect and take over. Then they force it to produce more of the same virus particles. They do this by combining the production mechanisms of the host cells and the blueprint for building a virus, which is encapsulated in the virus (in the form of DNA or RNA). Different viruses need different hosts. Depending on the virus, hosts can be plants, animals or humans. Sometimes a virus can infect certain kinds of animals as well as humans – it can switch the host.
There are even viruses that infect bacteria and fungi.
We named them bacteriophages and mycoviruses respectively.
There are no good viruses, but…
Yes, unfortunately, it is true – While there are many beneficial bacteria, fungi and protozoa not a single one of those little viral critters is good. They all cause disease and sometimes even death in bacteria, fungi, plants, animals and humans.
However, we make beneficial use of some viruses.
First, we use them to combat insects which are eating crops that we grow. For example, if an insect eats the so-called Baculovirus, it gets infected and dies.
Second, we can utilize bacteriophages to fight off bacteria that cause infections in humans. For example, you can treat meat that is potentially contaminated by harmful bacteria with bacteriophages. They destroy the bacteria making the meat safe to eat.
Finally, humans have developed and are developing technologies that use certain viruses to introduce new traits useful to us into plants and animals. In the near future, we will also be able to use such viruses to treat various diseases (such as hereditary diseases and cancer). We also use them to develop vaccines.
But is there any way to defend against bad viruses?
Fortunately, we have multiple ways to prevent getting infected by viral germs. There are also some options to treat viral infections. But they are less effective than preventative measures. To find out more on how to fight off germs click on the little critter below.