by Shawn Polson, Postdoctoral Researcher, University of Delaware

Viruses are everywhere: in the water we swim in, in the soil we walk on, and even in the most extreme environments of the deep sea.  Luckily for us, most of these viruses do not make humans sick, but prefer to infect bacteria, plants, other animals, or even . . . computers???  I’m sure you’ve heard about computer viruses and wondered what they have to do with the biological viruses that we hear about at the doctor’s office. 

You've probably already learned a bit about biological viruses.  These submicroscopic entities are made of the same biological components as living organisms. The viruses that infect computers are quite different. They are nothing more than computer programs composed of lines of code. How then did these two separate things end up with the same name? The key to this lies in looking at what the two types of viruses do.

Both computer viruses and biological viruses have very similar “lifestyles.” The primary goal of all viruses whether computer or biological, is to replicate (copy themselves), so that others of its kind can spread to infect  new hosts. In the case of a computer virus, the new host is another computer. In the case of a biological virus, the new host is a new cell. Biological and computer viruses are also similar in the way in which they replicate.  A virus by itself, whether a cold virus on a doorknob or a computer virus stored on a thumb drive, is powerless to do anything. It must just wait silently until it encounters a host. Once a human comes in contact with that doorknob or someone copies the file from the thumb drive, the virus is finally able to use the host’s own machinery to replicate itself.

There are even more similarities between the two types of viruses. Once inside a cell, a biological virus will do one of two things. It may immediately begin to replicate, very soon making so many copies of itself that it kills the host cell. Some computer viruses will also immediately begin copying themselves as soon as they infect a new computer, possibly even filling the hard drive or deleting important files which can cause the computer to stop working. 

The second possibility for a biological virus is that it can “hide” in the cell and then lie in wait. The virus can sit silently within the cell for long periods of time before stress or some other cue causes it to begin replicating.  Many computer viruses behave in a very similar way. They can enter a computer and immediately hide themselves in dark corners of the hard drive, waiting for a cue, such as a specific date before springing into action.

There are also many differences between the two types of viruses. One of the most important differences is that a computer virus is created by a person with the intent to cause problems for other people. Computer viruses do very serious damage to computers throughout the world each year. While biological viruses can cause illness, there is no such evil intent behind their actions. They are merely following their lifestyle as a part of the grand biological scheme of planet Earth.