Viruses and parasitic worms seem very similar on their surface (infecting other organisms) but are actually very different. The first major difference between the two is size; worms are much larger than viruses. Viruses are typically between one hundred and one thousand times smaller than worms. Worms are also much more advanced than viruses are. They don’t exactly have a brain, but they have a system that’s similar. Viruses are way simpler: they can’t think or make any action for themselves. Another difference is that viruses must hijack cells in order to reproduce. They are completely incapable of living outside of their host. Parasitic worms can make offspring on their own, but they live inside other organisms. The difference is a little confusing so think about it like this: worms hide inside other organisms and use some of their resources, like food. Viruses take over a specific cell and turn it into a virus-producing factory. Thank you for your question!

I never heard about viruses and worms being similar. Actually, they are quite different.

Aha! I googled them, and I see that they're similar in computers, along with 'trojan horses.' In biology, viruses and worms are totally different.

Viruses are so tiny they're not even as big as a cell. They have DNA, but they can't reproduce and replicate unless they're inside a living cell.

In comparison, worms are huge. Think of earthworms, which are so big that we can see them easily. There are lots of tiny worms, too, but they're still much much bigger than viruses. Some worms grow outside any host animal, like the earthworm. Some worms grow only inside an animal. But the worms that grow inside an animal only need to be in the animal to get their food. Those worms have lots of cells of their own that can replicate and make new cells. The worms grow, using their own enzymes. They just need to get their food from their host. Viruses need to use enzymes from their host in order to replicate.

Worms are animal that have long, slender bodies and no major limbs. Like all animals, worms' bodies are composed of many cells. Viruses are particles of RNA or DNA enclosed in protein that protect them, and are much smaller than even a single cell.

Being animals, worms have all of the biological capabilities necessary for reproduction. The only things that they need are energy and raw materials. Most worms are not parasites, and live freely in the water or soil, but those that are parasites get their materials from the host. They do not need information from the host, just energy and materials.

Viruses do not contain enough information in their DNA or RNA to create more of themselves. The process by which a virus reproduces involves using the information that they contain and combining it with the DNA from the host's genome, which is able to replicate itself. Having replicated themselves using the host's genome, they then break out of the host cell, killing it, and infect other host cells.

Both viruses and worms are parasites which means that they have a relationship with a host species in which they benefit, but the host is hurt. However, their mechanisms are very different.

Worms are animals so they are made of many cells and have many needs. By living in a larger animal host, they can get all of the nutrients they need from the host directly and eventually reproduce. Generally parasitic worms can’t survive without a host because they’ve evolved to be dependent on their host.

A virus is very different, it is technically not living so it doesn’t need nutrients. It’s basically just a package of genetic material that makes more copies of itself. It uses a cell’s machinery to copy its genetic material and then kills the cell once it has enough copies. The size relationship of a virus and a cell is similar in scale to the relationship of a worm and an animal. In other words, a worm is hundreds of times longer than a virus. So viruses and worms are similar in that they are parasites, but that’s really where the similarity ends. Viruses are non-living genetic packages that replicate using cellular machinery and worms are multicellular animals that feed off an animal’s nutrients.

There are actually many, many kinds of worms. Some are earthworms or leeches, but most are so small that you can’t see them without a microscope. They live in soil, plants, and just about everywhere else.

Worms are animals, so they are made of many cells, eat, and move. Like all living things, they take in nutrients and energy, give off wastes, grow, and reproduce. They usually need another worm to reproduce, but not always.

Viruses are like a super-parasite in some ways. They invade cells and turn them into virus factories. They do not use their own “machinery” to do this, they just insert their own directions (DNA or RNA) into the cell’s nucleus and let the cell do the work.

Viruses are not alive. They don’t take in energy and nutrients and give off wastes, they let the cell do that. They don’t grow. They are assembled by the cell. But they are like living things in some ways. They have DNA or RNA and are made by using energy to create order. They just don’t do the work.

We compared a virus to a worm. Now try comparing a virus to a book (ignore the size!). How is it more like a car then a worm or more like a worm than a book? Think about things like how it is made, information, energy, and growth.