Virus, Germ, or Bacteria?

What’s the difference between a germ, a virus, and bacteria? Everyday Einstein focuses his microscope to find out.

Lee Falin, PhD
4-minute read
Episode #90

Once harmful or “pathogenic” bacteria enters your body, there are a variety of ways that they can cause illness. Some species of bacteria cause infection of open wounds, others proliferate in your kidneys causing urinary tract infections. Other species affect the spinal cord, causing bacterial meningitis, while still others only grow in fluid inside the lungs, leading to bacterial pneumonia

Fortunately, many of these conditions can be treated with antibiotics - substances that either kill bacteria or slow down their growth enough to allow your immune system to deal with them. As wonderful as antibiotics are, they only work on bacteria (hence the name). 


Smaller even than bacteria, viruses are another type of object which cause illnesses in human. Notice that I said “object” and not “organism” and that's because there is some debate amongst scientists as to whether or not viruses are actually alive or not (although some of them look pretty sinister). 

A virus consists of a small piece of genetic material, (either DNA or RNA), surrounded by a small protein capsule. While each virus operates a bit differently, they all basically float around until they bump into a compatible cell. Then they attach themselves to the cell and inject their genetic material. The cell is then tricked into replicating the virus' DNA, using the instructions it contains to build more viruses, which then explode out of the cell, and the process continues.

Viruses can be useful for genetic manipulation because the part which makes them dangerous to humans is the genetic material contained inside the wrapper. That bit can be removed and replaced by beneficial genetic material to fix broken genes

Another beneficial use of viruses is as super-selective antibiotics. One of the problems with antibiotics is that they tend to wipe out beneficial bacteria along with harmful bacteria, which can sometimes do more harm than good. However a special type of virus, called a bacteriophage, targets and destroys specific types of bacteria, leaving other strains alone.


So now you know the difference between germs, bacteria, and viruses. As I mentioned, there are other types of things which fall into the “germ” category. Protists, certain types of fungi, and types of proteins call prions are other microscopic objects which can cause illness, but we’ll look at those in a future episode. 

If you liked today’s episode, you can become a fan of Everyday Einstein on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at everydayeinstein@quickanddirtytips.com.

Bacteriophage image, Carl Wirth at Flickr. CC BY SA-2.0.



About the Author

Lee Falin, PhD

Dr. Lee Falin earned a B.S. in Computer Science from the University of Illinois, then went on to obtain a Ph.D. in Genetics, Bioinformatics, and Computational Biology from Virginia Tech. 

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