Doctor Decoded: What’s the Difference Between Viruses and Bacteria?

Bacteria? Some good, some bad. Viruses? All bad.

Loading the player...

It’s so common to lump viruses and bacteria together in the same breath that you might trick yourself into thinking they are the same thing. While both viruses and bacteria can cause infections in the body, they are very different germs with very different treatments.

Bacteria are tiny organisms that look like rods, balls, or spirals, and they consist of just a single cell. In fact, they’re so small, you could fit a thousand bacteria across the diameter of a pencil eraser.

People commonly associate bacteria with illness, but the majority of bacteria are good for you. You naturally have tons of bacteria in your body at all times, and they help your body. You’ve probably heard of the good-for-you bacteria in your gut that helps with digestion, for example. There are also bacteria in your body that support the immune system to prevent diseases.

But of course, there are also more malicious bacteria, but infectious bacteria account for less than one percent of bacteria. You probably know many of them by name. E. coli can cause food poisoning (if digested) or urinary tract infections. Streptococcus, as the name suggests, can cause strep throat.

Infectious bacteria multiplies quickly in the body. Bacteria overgrowth produces toxins that can damage the tissues and lead to unpleasant symptoms. Bacteria infections can be treated with antibiotics.

Viruses are even tinier than bacteria. There is no such thing as a “good” virus; they are always dangerous.

Viruses work by taking your normal, healthy cells hostage, which allows them to reproduce. With the army of hijacked cells, the virus can damage and destroy other healthy cells in the area.

Viral infections can be temporary, such as the common cold or flu, or they can create chronic illnesses, like HIV/AIDS. Other conditions linked to viruses include mono, herpes, hepatitis, HPV, measles, polio, and rabies.

Because these are infections, many people mistakenly believe you can treat them with antibiotics, but these only work on bacteria. Some, but not all, viruses can be treated with antiviral medications. For others, like the cold or flu, you may just have to let the immune system do its thing. Luckily, there are also vaccines available to prevent some viral infections, most notably measles and polio.