In A Nutshell
Viruses and bacteria are two very different entities, and they can both be either beneficial or harmful. A virus is both living and non-living, and is incapable of reproducing on its own, while bacteria are complete, living organisms that can self-replicate. Bacteria are usually much larger, come in a wider variety of shapes, and serve in more beneficial roles than a virus.
The Whole Bushel
Infections and illnesses can be viral or bacterial. We often hear the terms, and we might even have a vague idea of what they mean. But a complete understanding of the difference between the two can help you treat the illnesses they cause.
A virus is essentially an organism that’s neither living or non-living. These tiny, microscopic things exist in two different states. When they are, for example, floating in the air or lying on a table waiting for someone to come by and inhale them, they’re non-living and inert. Once they are absorbed into a living host, though, they activate. A virus cannot replicate on its own, and requires a host cell to attach itself to in order to multiply.
Bacteria are tiny, living organisms that are not classified as either plant or animal—they’re simply bacteria. As such, they don’t rely on hosts in order to reproduce, and can exist, grow, and multiply outside of a living body.
A virus infects a living body by taking over the cells that it needs to reproduce. Before it comes in contact with these host cells, a virus is basically a tiny packet of genetic material. Once it attaches to another cell, it injects its own genetic material into the cell and forces the reproduction of its own material rather than whatever the cell had previously been responsible for creating.
A single bacterium contains more than a virus, as it has everything it needs to reproduce on its own. That means a cell wall, genetic material, and a flagellum (a little whip-like appendage) to propel itself around. It’s different from plant and animal cells, however, as there’s no nucleus to contain the genetic material.
When magnified, a virus looks like a round package. Bacteria can take a number of different shapes, including the ball-shaped or spherical bacteria, the rod-shaped, and the spiral. Within each general group of shape types, there are a wide variety that separates bacteria even further.
We generally think of viruses and bacteria as causing illness, but there are times where they’re beneficial, too. Bacteria in our digestive systems help to break foods down into components our body can use, and it’s bacteria that transforms oxygen into a form that plants can use. A virus can also be useful, although it’s perhaps less commonly thought of in that way. Because a virus will naturally attach itself to a healthy living cell, a virus can be used as a delivery system when genetic material needs to be transferred to a human body. Injecting a virus with genetic material then releasing it into the body can result in the delivery and replication of cells. This type of gene therapy is still highly experimental, but showing progress. Some types of viruses will also target and destroy some types of bacteria, like E. coli.
Because of their simplicity, a virus can be much, much smaller—up to 10,000 times smaller—than a bacterium. Examples of both can be found just about anywhere on Earth, in any environment, and in any extreme conditions.
Determining whether an illness is caused by bacteria or a virus decides how it’s treated. Bacteria are only vulnerable to antibiotics, while anti-viral agents are required to kill a virus, and vaccinations can help prevent them from infecting a body.