Viral Infections vs. Bacterial Infections

While both viruses and bacteria can cause a variety of infections that range from mild to serious, these are two very different things. Therefore, knowing the difference between viral infections and bacterial infections is highly important, since wrongful treatment may lead to much more serious health issues and even antibiotic resistance.

Viruses vs. Bacteria

Viruses and bacteria are tiny, which makes it impossible for us to see them. However, the similarities between the two terms end with the size and similarity in symptoms.

What is the difference between a virus and a bacterium?

A bacterium is a small, complex cell that can survive on its own. These are single-celled creatures that have a rubbery membrane, a rigid wall and fluid inside.

According to science, bacteria have existed for approximately 3 and a half billion years, which means that this microbe can survive in almost every environment, including radioactive waste, extreme cold and heat and of course, the human body.

Unlike what many people think, the majority of bacteria are not harmful. In fact, people have many bacteria both inside and outside their bodies that helps them in a certain way. For example, we have a lot of bacteria in the gut, helping us digest food, as well as bacteria that provide us with nutrients and fight cancer. Estimates say that less than 1% of bacteria cause diseases in humans.

A virus is smaller than a bacterium. Actually, the largest virus is smaller than the smallest bacteria.

All viruses have is a core of genetic material and a protein coat. And not only that. Viruses are actually not cells and unlike bacteria, they can only multiply inside a living host. This is how they work – by entering and multiplying inside our healthy cells.

Viruses are meaner than bacteria. Unlike the good bacteria that help us fight off diseases and provide us with nutrients, most of the viruses attack our body’s cells and cause diseases. In some cases, they even target the good bacteria in our body.

Viral Infection vs. Bacterial Infection

As you probably assumed already, bacteria cause bacterial infections and viruses cause viral infections.

Now that you know how different these terms are, you can understand the importance of knowing the source for the infection. It is only when a doctor knows whether viruses or bacteria caused an infection, that they know the best way to treat it.

Infections such as whooping cough, ear infection, strep throat and even urinary tract infection are examples of bacterial infections. Viral infections come in the form of the flu, the majority of coughs and bronchitis, HIV and AIDS, and chickenpox.

The biggest problem in diagnosing and treating infections lies in the symptoms. Unfortunately, both viral and bacterial infections can cause the same symptoms, which is why doctors use a patient’s urine, stool and blood sample to have the bugs identified.

Signs and Symptoms

As we said, symptoms are very similar with bacterial and viral infections. This is not strange since both infection types are caused by microbes and spread in a similar way, most commonly by:

  • Sneezing
  • Coughing
  • Contact with infected people, most often through sex and kissing
  • Contact with infected pets and other creatures, including insects
  • Contact with contaminated food, water and surfaces

If you are infected, you may experience the following symptoms:

  • Fever
  • Inflammation
  • Diarrhea
  • Fatigue
  • Vomiting
  • Cramping

Even though these infections are very similar in terms of signs and symptoms, they are dissimilar in a variety of other important respects, mostly in the way they respond to medications.

What Can these Infections Cause?

In both cases, microbes can cause different infections, such as:

  1. Acute infections (short-lived infections that do not necessarily require treatment)
  2. Chronic infections (can last for months and even a lifetime)
  3. Latent infections (can reactivate after a certain period of time)

Bacterial and viral infections can be the cause of mild, moderate and severe diseases. This is something we have noticed throughout history, especially when millions of people died of the Black Death or the bubonic plague.

In recent times, viral and bacterial infections are responsible for the following pandemics:

  • The Spanish flu of 1918-1919, which killed approximately 40 million people
  • The HIV/AIDS epidemic that is ongoing and has killed over 1.5 million people in 2013 alone

Diagnosis: Viral or Bacterial Infection?

Consult your doctor immediately if you think you have an infection. One of the exceptions for this rule includes the common cold, which usually does not require immediate consultation and is not life threatening.

Many ailments such as diarrhea, pneumonia and meningitis can be caused by viruses and bacteria. In cases such as these, the origin of the infection is difficult to determine. However, if you visit the doctor’s office, they can pinpoint the cause of the infection by doing a physical exam.

If necessary, the doctor may order a urine test, blood test or even a biopsy of a tissue affected by the infection.

After doing this, the doctor can confirm the diagnosis and set a proper treatment.

Treatment of Viral and Bacterial Infections


Did you know that bacterial infections’ antibiotics are known as some of the most important breakthroughs in medical history?

Still, bacteria can be very adaptable to the environment, which is why it exists for billions of years. When a person overuses antibiotics, this can make the bacteria resistant to them, which has caused serious problems.

Unfortunately, antibiotics are not effective in cases of viral infections. At this point, health organizations are against prescribing antibiotics unless it is clear that a patient is infected by bacteria.


Vaccines are developed since the beginning of the 20th century, after which they drastically reduced the number of viral diseases that include: polio, chickenpox and measles. In addition, vaccines are known to prevent infections such as: hepatitis A and B, the flu, human papillomavirus, etc.

Still, viral infections treatment is significantly more challenging than bacterial infections treatment. The main reasons for this lie in the fact that viruses are very small and can reproduce inside the human cells.

Did you learn the difference between bacterial and viral infections? This is a highly important thing to remember since, treating such infections depends greatly on the cause for the symptoms you are experiencing.

Fast, Private & Affordable STD Testing

Was this article helpful?