Difference Between Bacterial And Viral Infections

Diseases attributed to infections have plagued majority of the human population at some point of their life. While some of them might have been bacterial, the causative factor behind the others is virus. Common people fail to make out the differences between the infections caused by bacteria and virus, thus confusing one with the other. However, it is very important to make a clear-cut distinction between bacterial and viral infection for their proper treatment.

Difference Between Bacterial And Viral Infections

Difference Between Bacterial and Viral Infections In Terms Of Definition

Though there are a lot of similarities between bacterial and viral infections, the causative factor behind both being microbes – bacteria and viruses, there are certain differences between the two infections that one needs to be aware of.

Bacterial Infections: As is evident by the very term, bacterial infections are caused by bacteria. Bacteria may be defined as a single-celled microorganism that has the capability of thriving under a varied range of environmental conditions. Though a majority of the bacteria residing in our system are beneficial, there are bacteria that can cause a number of diseases. These are termed as pathogenic bacteria. It is this pathogenic bacterium that causes bacterial infections. They gain access to the body under favorable conditions and begin multiplying and crushing the immune system of the body, upon which the person succumbs to bacterial infections.

Viral Infections: Viral infections, on the other hand are caused by viruses, which may be defined as microorganisms that replicate inside the living cells of the body, termed as host cells. Viruses gain access to the living cells, thereafter, taking control of the cell mechanism, directing it to produce viruses.

Differential Symptoms: Difference Between Bacterial and Viral Infections Based on Symptoms

Before describing the difference in the symptoms between bacterial and viral infections, let’s take a look at some similar symptoms between both the bacterial and viral infections which include: fever, coughing, sneezing, inflammation, fever, vomiting, diarrhea, cramping and fatigue.

Certain diseases, such as pneumonia, diarrhea etc., can be attributed to both bacteria and viruses. However, there are certain distinctions in terms of symptoms between the two- while the symptoms of viral infections are widespread; those of bacterial infection are more localized in nature. While viral infections are generally operational in the respiratory tract of the body, bacterial infections can affect the skin, genitals and the intestines. However, a correct assessment may be made only after conducting certain pathological tests.

Spreading/Contamination Difference: Difference in the Spreading of Bacterial and Viral Infections

Both bacterial and viral infections can only affect the body, when they have successfully gained access to the biological system and have taken control of the mechanism causing considerable harm to the body.

Bacterial Infections: There are a number of ways in which pathogenic bacteria can enter the body, some of which are:

  • Consumption of contaminated water and food can cause bacterial infection.
  • Bacterial infection can spread via coming in contact with the feces of the infected person.
  • Inhaling the contaminated droplets of the infected person after he/she sneezes or coughs can spread and cause bacterial infection.
  • Bacterial infection can spread via open cuts or wounds.
  • Bacteria can also enter the body indirectly when the person comes in contact with contaminated surfaces, such as taps, nappies, toys and the like.
  • Upon entering the body, the pathogenic bacteria begin to replicate and multiply as soon as it finds favorable conditions, thereby causing bacterial infections.

Viral Infections: Disease causing viruses, on the other hand gain access to the body and spread by means of:

  • Coughs, sneezes and vomit spread viral infections.
  • Bites of contaminated insects and animals spread viral infections.
  • Contact or exposure to contaminated fluids of the body, such as those during sexual intercourse and the like also can spread viral infections.
  • Once inside the host cell, the virus takes control of the cell mechanism and directs it in the production of viruses, thereby, causing viral infection and diseases.

Difference In Body Response: Difference Between Bacterial And Viral Infections In Terms Of Reaction Of The Body

Bacterial Infections: The biological system is fashioned in a way that reacts differently to the attack of bacteria and viruses. In case of contamination by bacteria, the body increases the flow of blood to the infected area of the body thus, leading to inflammation as a way of reaction to the bacteria. The immune system produces antibodies, which then, latches to the pathogen, thereby, catalyzing its destruction. These antibodies also contribute significantly towards the destruction of certain pathogens, such as Diphtheria and Tetanus.

Viral Infections: Since viruses take refuge inside host cells, it becomes difficult for antibodies to destroy them. However, our body produces certain distinctive immune cells, called T-lymphocytes which are capable of recognizing and killing virus-containing cells. After their release from infected cells, these viruses are effectively destroyed by the antibodies produced as a result of immunization or as a reaction to the infection.

Differential Treatment: Difference Between the Treatment of Bacterial and Viral Infections

Bacterial Infection: Medical science has come a long way in terms of treatment of bacterial and viral infections. The manner of treatment of diseases caused by these microbes varies to a considerable extent. Bacterial infection can be easily treated with the help of antibiotics, which destroy the metabolic system of the bacteria. However, bacteria can easily adapt to changing environmental conditions. Hence, the overuse of antibiotics makes them resistant to the same. Under unfavorable conditions, some of the bacteria develop a hard external cover and morph into an inactive state. These are called spores and are harder to kill than the living counterparts.

Viral Infection: Viruses are, however, more difficult to kill as they reside inside the living cell and antibiotics are ineffective when it comes to treatment of viral infections. Since, they reside in the host cells the antibodies produced by the body’s immune system find it difficult to destroy it. Patients suffering from viral infections are prescribed anti-viral drugs, which inhibit the working of the viral enzymes. However, these drugs are effective only on certain diseases, such as influenza, herpes, hepatitis A, B etc. Interferon, a naturally developing protein, which can now be produced artificially, is given to patients suffering from Hepatitis C and other such viral infections.

Prevention from Bacterial and Viral Infections

Observing certain daily- life cautions can also reduce the possibilities of being affected by these microbes to a great extent. These include:

  • Observing rules of hygiene- washing hands after coming in contact with infected person or contaminated surfaces helps in preventing bacterial and viral infections.
  • Abstaining from smoking, as it weakens the immune system, thereby, making it easier for the microbes to infest the system.
  • Ensuring hygienic toilet facilities before and after defecating to prevent bacterial and viral infections.

What are some Common Bacterial Infections?

A majority of the bacteria have been found to be beneficial with only a small percentage being pathogenic in nature. These disease-causing bacteria enter the system and outnumber the healthy bacteria present in the body. Some of the common diseases caused by bacteria are-

  • Urinary Tract Infections– caused by Escherichia Coli
  • Whooping Cough– caused by Bordetella Pertussis
  • Tuberculosis- caused by Mycobacterium Tuberculosis
  • Diphtheria- caused by Corynebacterium Diphtheriae
  • Tetanus- caused by Clostridium Tetani

What are some Common Viral Infections?

Common viral infections, on the other hand, include:


Bacterial and viral infections are very common. A large majority of the population have succumbed to them at some point in their lives. Since the many of the symptoms of bacterial and viral diseases are almost the same, common people are often unable to make a distinction between the two. As a result it often comes in the way of proper treatment of the diseases. Therefore, it is quite imperative that one is well aware of the differences between these two kinds of infections. Noticing the symptoms, causes and location of the affected area can tell which kind of infection it is to some extent. It is important to consult your physician ASAP if you illness is not subsiding. You doctor is the best person to differentiate between bacterial and viral infections and treat you accordingly.

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:December 27, 2018

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