Viruses vs Bacteria: What’s The Difference?

We have all been sick with a viral illness at one time or another in our lives.  As a matter of fact, viruses are one of the most common causes of fever in children. So you may be wondering exactly what a virus is.  It is a molecule with genetic material, it can only replicate inside of the living cells of another organism.  The virus’s genetic material takes control of the host cell and forces it to reproduce.  Viruses can infect all types of life forms, including plants, animals, and bacteria.  There are over 320,000 different viruses that infect mammals.

How do you contract a virus?  People may get viruses by swallowing or inhaling them, by being bitten by insects or through the exchange of bodily fluids.  There are many types of viruses and they can cause a variety of symptoms.  The influenza virus causes a cough, congestion, body aches fevers, and sore throat, while the Norwalk virus is the most common cause of acute infection of the stomach and intestines causing diarrhea, vomiting, nausea and stomach pain. Some viruses cause life-threatening illnesses, such as human immunodeficiency virus.  Other viruses, such as the rhinovirus, which is also known as the common cold, causes mild illness with symptoms such as nasal congestion, sneezing, and cough.

You may be wondering how a viral infection is different from a bacterial infection.  Well, the virus invades a normal living cell and uses those cells to multiply and reproduce which eventually kills the cells.  The virus is taking up residence inside the cell and this provides the virus with protection from medicines that move through your bloodstream.  The viral particles are using your own healthy cells to reproduce, so to kill the viral particles, the cell in which they reside would also have to be killed. This would be harmful to the host, which is you.

Bacteria are single cell organisms that can reproduce independently of the host.  They cause infections such as such as strep throat, urinary tract infections, and pneumonia.  These organisms are susceptible to antibiotics and individuals can be treated with the appropriate medication to kill the bacteria.  Antibiotic medications are selected based on the type of bacterial infection.  So a different antibiotic would be selected for pneumonia versus a urinary tract infection.  Antibiotics may have side effects but are usually safe for most individuals.

So the bottom line, viral infections are not susceptible to antibiotics.   For example, there are medications such as oseltamivir (trade name Tamiflu) that halt the progression of the influenza virus.  This medication does not kill the influenza virus because, in order to kill the virus, the host cell would also have to be destroyed.  Antiviral medications can decrease the length of the illness because they can disrupt the reproduction of the virus in your cells.  If you are infected with a viral illness, most of the treatment is supportive care, such as taking medication to control fevers, drinking plenty of fluids, and resting to allow your body time to heal.  Bacterial infections can be treated with antibiotics because they are not using the host’s cells to reproduce.  With the use of antibiotics, the bacteria causing the illness can be killed and eliminated. Because the bacteria can be killed, most individuals will see an improvement in his or her symptoms in about 2 days.

Vaccination is the best method to prevent many of the viral illness that cause diseases, such as the MMR, which protects against measles, mumps and rubella and the flu vaccine which protects against specific strains of the influenza virus.  Go to www.CDC.gov for a complete list of vaccines and immunizations.