What is the difference between bacteria and viruses?

Both bacteria and viruses are so small that they can only be seen through a microscope, and both have the ability to cause infection and can spread in many same ways. You could say they have a lot in common, but at the same time they have as much in common as a giraffe and a hummingbird — not much at all.

Microbes (bacteria and viruses) can both spread by things such as:

Coughing and sneezing.
Contact with infected people, especially through kissing and sex.
Contact with contaminated surfaces, food, and water.
Contact with infected creatures, including pets, livestock, and insects such as fleas and ticks.
Infected blood or other body fluids

Microbes can cause:

Acute infections, which are short-lived.
Chronic infections, which can last for weeks, months, or a lifetime.
Latent infections, which may not cause symptoms at first but can reactivate over a period of months and years.

Bacteria

Bacteria are single-celled micro organisms that can be found naturally throughout our bodies and thrive in many different types of environments. Some varieties live in extremes of cold or heat, others make their home in people’s bodies, where they help digest food, protect us against other bacteria or microbes, and provide nutrients for our body. Most are harmless and do not cause infection. Seen under a microscope they look like rods, balls, or spirals, and like viruses they can multiply quickly under the right conditions.

Most bacteria cause no harm to people as less than 1% of bacteria actually make us sick, but there are exceptions.

Infections caused by bacteria include:

Strep throat
Tuberculosis
Urinary tract infections

While antibiotics are available to treat most bacterial infections, inappropriate use of antibiotics has helped create bacterial diseases that are resistant to treatment with different types of antibiotic medications. It is often best to let your body’s own immune system fight them if it is able to.

Viruses

Viruses on the other hand are smaller than bacteria (the largest of them are smaller than the smallest bacteria) and cannot live without a living host. They require people, plants or animals — to multiply, otherwise they can’t survive for long. When a virus enters your body, it invades some of your cells and use that cells’ genetic material to reproduce themselves.

Although viruses are classified as microorganisms, they are not considered living organisms. Unlike bacteria, they behave as living organisms only in the body of the host organism. Viruses are not made out of cells. Instead, a single virus particle is known as a virion, and consists of nucleic acids (DNA or RNA) bundled within a protective protein shell.

Unlike bacteria, most viruses cause disease.

Diseases caused by viruses include:

Chickenpox
AIDS
Common colds
Herpes
Shingles
Measles

In some cases, it may be difficult to determine whether a bacteria or a virus is causing your symptoms. Many problems — such as pneumonia, meningitis and diarrhea — can be caused by both.

Antibiotics will not treat a viral infection. Viral infections require either vaccinations to prevent them in the first place or antiviral drugs to inhibit their development (unlike most antibiotics, antiviral drugs do not destroy their target pathogen). Most antivirals are used for specific viral infections, while a broad-spectrum antiviral is effective against a wider range of viruses.

You should consult your doctor if you think you have a bacterial or viral infection.

Basic coronavirus related questions: