Medical Science - Other

Difference between a Virus and Bacteria

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People toss around the words, bacteria, bacterial infection, and virus, all the time.  But most don’t understand the differences between the two.  While it is true that both bacteria and viruses cause illness, their structure, reproduction method, and function are very different.

Differences in Structure:

A virus is not a cell and, thereby, does not have a cell’s structure, i.e., a cell wall, an internal cellular structure or a cell membrane. 

Bacteria are unicellular (single-celled) organisms. 

Bacteria live in-between cells, while viruses live inside the cell. 


To reproduce, a virus must find a cell to host them (or take them in).  Once the virus has been allowed to penetrate a cell, the cell itself begins making copies of the virus.  When it is ready, the virus breaks through the cell, finds more cells and repeats the same process over and over. 

Bacteria, on the other hand, reproduce asexually by splitting in two and making exact copies of themselves.  This form of reproduction is called binary fission.


Humans can survive without viruses because viruses don’t perform any beneficial function for the host.  AIDS is a virus, and so are chickenpox and the common cold.

Bacteria can either cause disease, or they can do good things for the body.  While it’s true that bacteria can cause diseases like pneumonia and strep throat, they also help make vitamins and help the body to metabolize nutrients. 

Good hygiene and public health practices are the first line of defense in warding off viruses and bacteria.

Curing Disease:

Diseases caused by viruses are treated differently than diseases caused by bacteria. 

There is no cure for the virus.  The only thing that you can do is lessen the symptoms.  You can take aspirin for fever or use cough medicine to quiet a cough.  But the actual virus has to run its course until it is eradicated by the body’s immune system.

Antiviral drugs are relatively new and will not cure a virus.  They will, however, suppress the virus and, thereby, make the damage to the host less severe.

Infectious diseases (caused by bacteria) are treated by antibiotics, which kill off the bacteria and cure the disease.


Beilach, A. (2010). Understanding the Differences Between Viruses and Bacteria, and how to Protect Yourself. FactOidz. Retrieved on January 26, 2011, from

Gut flora. (2011). WIKIPEDIA, Retrieved on January 26, 2011, from

Musab, J. (2010). How to Know the Difference Between Bacteria and Viruses. WikiHow. Retrieved on January 26, 2011, from

Steckelberg, M. (2009). Infectious diseases. Mayo Clinic. Retrieved on January 26, 2011, from

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