Virus or Bacteria?

Viruses are only one kind of microbial invader. In fact, many of history’s deadliest diseases have bacterial, rather than viral, causes. Take the infamous Black Death, or bubonic plague, which wiped out a third of Europe, China, and the Islamic world in the 14th century. Or tuberculosis, an ancient airborne disease that rose to alarming prominence in the 19th century as humans packed into crowded cities.

Don’t blame viruses for these scourges. Blame bacteria, which are another kind of “germ” entirely. Here’s a quick look at the not-so-microbial difference between the two.

Size

Compared to viruses, bacteria are big – big enough, in fact, to be attacked by viruses that target them. You can see bacteria using a science-class microscope that magnifies them a thousand times. But to look at viruses, you need an electron microscope that magnifies them a million times.

Imagine it this way. If just one of the 10 to 100 trillion cells in your body were the size of a baseball park, the average bacterium would be the size of the pitcher’s mound. The average virus would be the size of the baseball.

Survival

Viruses are not cells. They’re just a few strands of rogue DNA (or RNA) looking for a free ride. They lack the components required for metabolism and replication, so they have to hijack host cells and exploit their machinery to create copies of themselves.

Bacteria are self-sufficient one-celled organisms. They have a cell wall to contain their intracellular machinery, they have a metabolism of their own, and they can live inside or outside other organisms. They reproduce independently – replicating DNA, then splitting in half, so that each new cell is exactly like the parent cell. In good bacterial weather, a single bacterium can become a billion bacteria in just 10 hours.

Sickness

Viruses sicken you when they seize your body’s cells and make them do their reproductive bidding. Bacteria sicken you when they digest your cells as food, or secrete toxins, or replicate rapidly in a sensitive spot. Antibiotics can kill bacteria but can’t stop viruses, since they work either by destroying the bacteria’s cell walls or by gumming up their intracellular machinery – and viruses have neither.

Unfortunately, it’s not always easy to distinguish between viral and bacterial infections, because the symptoms often feel the same (and are often self-inflicted collateral damage as your immune system returns fire). You know soon enough, though. Viral infections tend to get better after the first few days, while bacterial infections get worse over time.