Bacterial vs Viral Infection: What’s the Difference?

Both bacteria and viruses can cause infections and human illnesses. Please keep reading to learn some key differences between a bacterial or viral infection.

What are the major differences between viruses and bacteria?

Type of organism

Bacteria are tiny single-celled microorganisms that are not visible to the naked eye. They can survive in many different types of environments, both with and without a human host. Most bacteria are not harmful, and some are even helpful, like gut bacteria that help to digest food. However, some disease-causing bacteria can cause bacterial infections and severe disease in humans.

Viruses are smaller than bacteria. Unlike bacteria, they are not cells. Instead, they are bits of genetic material surrounded by protein. Viruses need a host (animal or plant) to survive. They cause viral infections by entering healthy host cells and multiplying to make more copies of themselves.

Types of infections

Examples of bacterial infections include strep throat, urinary tract infections, ear infections, whooping cough (pertussis), tuberculosis, salmonellosis, and tetanus.

Examples of common viral infections include colds, COVID-19, norovirus (stomach flu), chickenpox, HPV (warts), herpes simplex virus (cold sores), and HIV.

It is worth noting that either bacteria or viruses can cause some of the same infectious diseases, such as diarrhea, pneumonia, and meningitis. Your healthcare provider will need to obtain a sample of urine, stool, blood, or throat swab to find out what kind of infection you have.

Also, secondary infections can occur during or after treatment for another infection. This can be due to effects on the immune system or the treatment for the first infection. For example, secondary bacterial infections in the lungs (pneumonia) can develop after upper respiratory infections caused by viruses. Vaginal yeast infections can develop after taking antibiotics to treat serious bacterial infections.

Transmission

Both viral and bacterial infections spread to the human body through cuts in the skin, breathing droplets from an infected person, eating or drinking contaminated food or water, touching contaminated surfaces or objects and then touching your nose, mouth, or eyes, skin-to-skin contact, and contact with blood and other bodily fluids.

Treatment

Antibiotics are used to treat a bacterial infection. These drugs kill bacteria or prevent them from growing, but they are useless against viruses. It’s important to take antibiotics only for bacterial infections and not viral infections. Also, you should take antibiotics exactly as prescribed to prevent bacteria from becoming resistant to these life-saving drugs. Antibiotic resistance can make common bacterial infections harder to treat in the future.

Many viral infections clear up without any specific treatment. Sometimes, antiviral medications are used to treat viral illnesses. These drugs stop viruses from entering a host cell or making copies of themselves in the host cell. An antiviral medication may need the host’s immune system to fight a viral infection. Like bacteria, viruses have also developed resistance to antiviral drugs, affecting treatment.

Which are more serious, viral or bacterial infections?

Generally speaking, the body’s immune system can fight diseases caused by viruses more easily than those caused by bacteria. Therefore, viral infections tend to cause less severe symptoms than bacterial infections and may not require specific treatment other than supportive care. With that said, treating viral infections can prove to be more challenging than treating bacterial infections because viruses are tiny and reproduce inside cells.

How to tell if it is a viral or bacterial infection?

It can be hard to tell if your infection is caused by pathogenic bacteria or viruses. Many bacterial infections and viral infections cause similar symptoms, such as fever, fatigue, cough, sore throat, sneezing, runny nose, nasal congestion, inflammation, diarrhea, and vomiting.

Additionally, many common infections can be caused by both viruses and bacteria, for example, diarrhea, pneumonia, and meningitis.

Your healthcare provider will obtain a medical history, carefully review your symptoms, and order lab tests such as a complete blood count or white blood cell count to find out if you have a bacterial or viral infection. They will offer appropriate treatment after making a diagnosis. Again, viral infections cannot be treated with antibiotics.

How do you treat bacterial and viral infections?

Viral infections often go away on their own without any specific treatment. In some cases, your healthcare provider may prescribe an antiviral medicine for a viral infection. Antibiotics are used to treat bacterial infections.

Whether your healthcare provider gives you antibiotics or antiviral medicines, take them exactly as prescribed. Finish the full course of treatment even if you are feeling better and your symptoms are gone. This is important to prevent the emergence of antibiotic-resistant bacteria and antiviral-resistant viruses.

How to prevent viral and bacterial infections?

The following tips can help to prevent viral and bacterial illnesses:

Practice good hand hygiene. Wash your hands thoroughly with soap and water.
Avoid touching your face with your hands as much as possible.
Stay away from people who are sick, and stay home if you are sick.
Cover your nose and mouth when you cough or sneeze.
Clean and disinfect frequently touched items such as door knobs.
To prevent food poisoning, follow food safety tips, such as keeping food preparation surfaces and equipment clean and disinfected.
Take steps to prevent sexually transmitted infections, such as using condoms and practicing mutual monogamy.
Get the recommended vaccinations, for example, the flu vaccine, before every flu season.
Take antibiotics and antiviral medications as prescribed to prevent antimicrobial resistance.