Difference between Viral and Bacterial Infections

Updated on December 12, 2017

Infection occurs when organisms grow in number causing damage to tissues. Without proper treatment it can lead to more serious disease. The two most common organisms that infect humans are viruses and bacteria. This article will discuss the differences between the two said infections.

Definitions

Viral Infection
Examples of viral infections and which body parts they affect

Viral infections are diseases caused by a virus. Viruses need a living host (humans, animals, or plants) to survive. Once a virus has infected the human cell, it transfers its genetic code to the human cell allowing it to replicate and cause infections. Examples of viral infections include influenza, the common cold, coughs, chickenpox, mumps, and HIV. The most common symptom for any viral infection is fever and malaise. Some viruses can also cause abdominal pain, diarrhea, coughing, and shortness of breath.

Bacterial Infection
Examples of bacterial infections and which body parts they affect

Bacterial infections are diseases caused by an overgrowth of a virulent strain of bacteria that attack a weakened immune system. The single-celled bacteria can thrive in the human body without causing harm, for example gastrointestinal bacteria that help digest food. But when there is an increase in number, it becomes pathogenic and/or the immune system weakens, it can cause a bacterial infection. Examples of bacterial infections include pneumonia, tuberculosis, gastritis, and urinary tract infections.

Comparison Chart

Viral InfectionBacterial Infection
Etiologic agents are virusesEtiologic agents are bacteria
Viruses need a host to survive in order to cause harmBacteria can live in the human body without causing harm
A Virus transfers its genetic code to the human cell allowing it to replicate and cause infectionsBacteria divide and multiply causing infection
Mode of transmission includes coughing, sneezing, inadequate personal hygiene, animal or insect bitesMode of transmission includes close contact to an infected individual, food or water contamination, cuts and abrasions
Clinical manifestations may or may not include fever, phlegm is clear or cloudy in color, and the source of infection cannot easily be locatedClinical manifestations include fever, phlegm that ranges in color from green to yellow to bloody or brown-tinged, and they are site specific
Medication is antiviral drugsMedication is antibiotics
Infections can last 10 daysInfections can persist for 2 weeks

Viral Infection vs Bacterial infection

What is the difference between viral and bacterial infections? Let us compare them in terms of etiologic agent, size of the etiologic agent, how they survive, how they cause infection, mode of transmission, clinical distinction, medications taken, and duration of treatment.

  • The most evident difference between viral and bacterial infections is the etiologic agent or what causes the infection. Viral infections are caused by viruses. As for a bacterial infection, it is caused by the single-celled bacteria.
  • Both viruses and bacteria are microscopic size. But a virus is smaller than the smallest bacteria. Due to the size, it can hide in between cells and places where the host’s immune system cannot reach it. Bacteria are bigger compared to viruses.
  • There is also a difference on how their etiologic agents thrive. Viruses, for a viral infection, need a host (it could either be a human, animal, or plant) to survive in the process causing harm. Without a host the virus dies. On the other hand, bacteria, for bacterial infection, can live inside the human body without causing any harm, for example gastrointestinal bacteria that help in digestion. Bacteria can only cause harm when there is an increase in pathogenicity or the immune system weakens.
  • Viruses replicate inside the body via transferring their genetic codes to the human cell thereby causing infection. Bacteria simply divide and multiply causing infection and harm.
  • The mode of transmission for viral infections includes coughing, sneezing, inadequate personal hygiene, and animal or insect bites. Bacterial infections are transmitted via close contact to an infected individual, food or water contamination, and cuts and abrasions.
  • There are a few simple clinical manifestations that can help an individual identify whether they have a viral or bacterial infection. A viral infection may or may not include fever; phlegm is clear or cloudy in color, and the source of infection cannot easily be located. Bacterial infections on the other hand manifest as fever, with phlegm that ranges in color from green to yellow, bloody  or brown-tinged, and they are site specific. Furthermore, symptoms of viral infections can persist for more than ten days. Consult a medical doctor if you are in doubt as to what type of infection you have.
  • To treat infections one would need ample rest, proper hydration, and adequate nutrition. Aside from this, medications will be needed. To treat viral infections, one is given antiviral drugs. However, not all viral infections have a corresponding antiviral drug.  Certain viral infections have no medication – at first this was the case for HIV. As for bacterial infection, antibiotics are given. Never self-medicate, especially with antibiotics. Bacteria have the capability to adapt and resist to antibiotics if improperly taken.  To know which would be the appropriate medication and dose, consult your doctor.
  • Viral infections take 10 days to be cured, while bacterial infections last longer, about two weeks.

Video

The following video could help you better understand the difference between viral and bacterial infections:

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