A parasite is something that harms an individual of one species (host) and helps an individual of another species (parasite). It’s different from predation because in predation, the victim has to die for the predator to get the benefit. A host sometimes dies from having too many parasites, but if that’s just a side effect, it still isn’t predation. Sometimes a parasite does better the longer its host lives. For example, if a tapeworm is living in someone’s gut, the worst thing that can happen for the tapeworm is for its host to die. With a parasite like a tick, it doesn’t really matter to the tick whether you live or die after it takes your blood. Parasites and hosts don’t have to be animals. For example, vines might grow on top of other plants, using the big plant’s height and taking sunlight away from the host plant’s leaves. An insect might burrow into a tree and take its sap.

Viruses move into cells and turn them into virus factories. The cell usually bursts when it fills with viruses. The cell that they take over could be one in the lining of your nose or the leaf cell of a tree.

Viruses are not technically alive, but they’re close. The nose or leaf cells are alive. So what do you think? If you are not 100% sure, keep in mind that we humans like to make neat and tidy categories, but the natural world doesn’t always fit in neatly.

Great question! We cannot describe viruses as being truly parasitic for a few reasons . First, parasites are living organisms that live in or on another organism (the host) and take away nutrients from the host for the parasites own growth. Although there has been a lot of debate about whether viruses are living organisms, most virologists (scientists who study viruses) agree that they are non-living because they do not meet all of the criteria for life. Second, viruses are able to live outside of a host body while parasites are dependent on a living host to survive. However, parasites and viruses are similar in that they can both cause damage to other living organisms that live inside. Although they have some similarities, we are not able to call viruses parasitic.

Yes, in terms of how they interact with (other) living things, viruses are usually parasites (although not always).

Viruses are generally considered to be parasitic since their survival always steals away resources from their host. Often viruses will deliberately harm the host and sabotage its ability to fight back. Though generally when people use the term “parasite”, they are specifically referring to parasitic organisms that aren’t bacteria or viruses such as worms or the organism that causes malaria. So generally viruses are problematic for the host organism which makes them parasites. Interestingly enough, this isn’t always clearly the case. Nature is complicated so sometimes what seems like a negative for the host can actually be a positive. For instance, certain viruses prime the body to attack against bacteria so can be helpful. Also, bacteriophages which are viruses that infect bacteria can help protect a human from bacteria. There are even viruses that can make a plant drought tolerant! In these cases,whether a virus is parasitic or mutualistic (benefiting both organisms) is more complicated. The virus may still cause some harm, but also has a role in benefiting the host.