Healthy Living

Viral vs. Bacterial Infections: Know the Difference

Viral vs. Bacterial Infections: Know the Difference


Both bacterial and viral infections are caused by microbes, such as bacteria and viruses. These microbes are spread through the following:

  • Coughing
  • Sneezing
  • Direct contact with infected people, particularly through kissing and sexual intercourse
  • Exposure to contaminated food, water, and surfaces
  • Direct contact with infected living creatures, such as livestock, pets, and insects (ticks and fleas)

Both types of infection can cause mild, moderate, and severe diseases. They can also cause the following infections:

  • Acute Infection - A rapid but short-lived disease
  • Chronic Infection - A type of infection that can last for weeks, months, or a lifetime
  • Latent Infection - This type of infection may not initially cause symptoms, but can be reactivated after months or years.

There were millions of death throughout history that were caused by bacteria and viruses. They include the bubonic plague caused by bacteria called Yersinia pestis and smallpox from the variola virus. In recent times, viral infections are responsible for two major pandemics: 

  • 1918 Flu Pandemic or the Spanish Flu - A deadly flu strain that killed approximately 20-50 million people, including 675,000 Americans. 
  • HIV/AIDS - The human immunodeficiency virus or HIV is the virus that causes acquired immune deficiency syndrome or AIDS. It is a spectrum of conditions caused by an HIV infection. According to the World Health Organization (WHO), there are 36.7 million people living with HIV/AIDS worldwide in 2016. 

Other similar symptoms that are caused by bacterial and viral infections include:

These symptoms are some of the immune system's ways of getting rid of infectious organisms that harm the body. However, bacterial and viral infections also have differences, particularly in their structure and how they respond to medications. 

What are the differences between viruses and bacteria?

Bacteria and viruses are not visible without using a microscope. Bacteria are single-celled microorganisms without a nucleus or organelles. Their genetic information is contained in a DNA loop. There are some bacteria that have another circle of genetic material called a plasmid, which carries genes that provide bacteria with advantages, such as resistance to antibiotics. 

Bacteria can also reproduce on their own, and are able to survive in different environments, such as the human body, extreme temperatures, and radioactive waste. According to fossilized records, bacteria have existed for approximately 3.5 billion years. Most bacteria do not cause harm and can help kill disease-causing microorganisms, digest food, provide essential nutrients, and fight cancer cells. Less than 1 percent of bacteria actually cause diseases in humans. 

Viruses are tiny. The largest viruses are even smaller than the smallest bacteria. Viruses contain nucleic acid, which is either RNA or DNA, and has a protein coat that encases it. Viruses are different from bacteria since they cannot survive without a host. They also attach to cells to reproduce. Most of the time, viruses tend to reprogram cells to create new viruses until the cells die. In certain cases, they can also turn normal cells into cancerous cells. 

Another difference between bacteria and viruses is that viruses cause disease. They are also very specific when it comes to the cells they attack. There are viruses that particularly target the cells in the blood, respiratory system, or liver. Viruses can also attack bacteria in some cases. 

What is a viral and bacterial infection?

A viral infection is the proliferation of a harmful virus present in the human body. Since viruses cannot reproduce without a host, they attack the host by introducing their genetic material into the cells and take control of the cell's internal machinery to be able to produce more viral particles. 

There are also some viruses, such as those that cause cold sores and chickenpox, that hibernate or become dormant if they do not have a host to infect. They can easily spread from one individual to another through exposure to infected water droplets in the air from a cough or sneeze of an infected person. Other viruses are spread due to poor personal hygiene, especially when people do not properly wash their hands after using the toilet. Viruses can also be found on the surfaces of telephones, remote controls, or door knobs. For this reason, it is very important to practice good handwashing habits, especially when using public amenities. 

Other viruses can spread through body fluids, sharing of contaminated needles, and sexual intercourse. Viruses can also be transmitted by insects, such as ticks and mosquitoes. People can also get viral infections through the consumption of contaminated food and water. 

The human body contains more bacteria than cells. They normally reside on the skin and bowels. Although most bacteria are harmless, other types of bacteria can also cause infections that can harm the body. Bacterial infections can affect the skin, throat, lungs, bowels, and other parts of the body. In some cases, bacterial infections can also become severe. Antibiotics are used for the treatment of bacterial infections. However, when it comes to viral infections, antibiotics are not effective. 


See a doctor if you suspect that what you have is a viral or a bacterial infection, except for the common cold, which is often not life-threatening. Doctors will be able to determine the type of infection you have by getting your medical history and doing a physical examination. However, there are some cases that require further testing to determine the exact cause of the infection. Diarrhea, meningitis, and pneumonia are illnesses that can either be due to viruses or bacteria. 

Blood and urine tests can also help confirm a doctor's diagnosis. A culture test can specifically identify the presence of viruses and bacteria, and a biopsy can be done to identify the presence, cause, and severity of the disease. 


One of the most significant breakthroughs in medical history is the discovery of antibiotics. However, it is unfortunate that bacteria are highly adaptable. When antibiotics are frequently and inappropriately used, bacteria can become resistant and cause serious health problems, especially in healthcare settings. Viruses are not treated using antibiotics. Most leading health organizations do not recommend antibiotic use without proof of a bacterial infection. 

Vaccines have been developed since the 20th century, and have effectively reduced the cases of viral diseases, such as measles, polio, and chickenpox. Widespread vaccination can prevent infections such as hepatitis A and B, flu, and the human papillomavirus (HPV), among others. 

Treating viral infections can be challenging since viruses are tiny and replicate inside the cells. However, antiviral medications are available for certain viral diseases, such as HIV/AIDS, herpes, and influenza. Unfortunately, the use of antiviral medications may lead to the development of antimicrobial resistance.