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Viruses: Top 10 Questions

November 2006

Thanks to Dr. Christine Hahn and Dr. Joseph Hornby for the answers.

1: Why are scientists not sure whether or not a virus is a living thing?

That's a very good question. It really boils down to the question, "What is life? What does it mean to be alive?" That's not really a purely scientific question. That's also a philosophical question. People have different opinions about what exactly is life. I think viruses don't meet what many scientists feel are the necessary minimum criteria for life. But there are other scientists that would say that because viruses can make copies of themselves, that means they are alive. That is one thing that's fun and exciting about science — it's not all cut and dried. There's room for argument. (From Rachel in Caldwell)

2: What do viruses feed on?

The major goal of a virus is to survive and to make copies of itself. Viruses really don't eat anything. They infect or enter into a cell called the host cell and then they basically use proteins and various parts of that host cell to make copies of themselves. Then they will leave that cell and go find more cells to invade and infect. So, they really don't eat anything. (From Ristan from Potlatch)

3: How do you get rid of a virus?

Often times your own immune system does the trick. Your own body will get rid of a virus that is trying to infect you. Some viruses can take a strong hold and you will need some medication for treatment. In some cases, we haven't found a way to get rid of certain viruses, so they may stay with you for the rest of your life, things like cold sores or canker sores. We have been able to eradicate one virus, smallpox. Compared to other viruses, smallpox was a little easier to get rid of. There's a vaccine that's very effective. Young kids probably never got this shot, but if they look at their parents' arms they can see a scar. It's a vaccine which causes a big scar. But a good vaccine was key to eradicating smallpox. Secondly, smallpox doesn't live outside a human so you don't have an animal host or place to get rid of too. Other viruses, like West Nile virus, one where birds can get it and mosquitoes can carry it, will be a bigger challenge to eradicate. (From Aubrey in Hailey)

4: What's the difference between a virus and bacteria?

Both viruses and bacteria are germs, of course, and they can both make you sick. Viruses though are much smaller and much simpler than bacteria. Bacteria are pretty complex little cells. They have a lot of intricate structures. Viruses are a very super simple little outfit, usually a shell with some genetic information inside. (From Mallory in Mrs. Wells' fourth grade class)

5: How did we find the first vaccine for viruses?

That one is a really interesting story. It was a very brave experiment on the part of a small boy. There is a similar disease to smallpox called cowpox. Cows carried this virus and it was noticed that milk maids, the young ladies who worked around cows a lot, didn't tend to get small pox as often as others. You always heard that term, "pretty as milk maid"? That phrase came into use because milk maids seemingly weren't scarred from small pox. So based on that theory, scientists took a little boy and purposely gave him cowpox and then, once he had recovered, exposed him to small pox. I can't imagine what mother agreed to that, but the little boy survived and did just fine. So, that was a huge step forward in proving that if you got exposed to one virus or something close to that virus, your body could build up an immunity and then you wouldn't get sick. The first actual use of what we call vaccinations, or vaccine was 60 or 70 years before that. In the early 1700s, there was a woman, Mary Montague, who was a writer from England and whose husband was an ambassador to what is now Turkey. She actually had small pox and was terribly scarred from it. She saw that the local women were doing something called engrafting, where they would take fluids from a person who had a certain type of small pox, one that isn't as deadly or damaging, and infected other individuals. She did that to her own son to protect him from what she had. (From Becky in Jerome)

6: What is the most dangerous virus?

Most likely, [something] like the Ebola virus, which tends to be very difficult to control once it infects an individual. It also has a fairly high mortality rate and can lead to quite a few deaths. I'm going to throw in what I think is a virus that's closer to home for most of us, in Idaho. The rabies virus, which exists in Idaho and is mostly in bats in Idaho, is very dangerous. It is a good reason to avoid bats and not touch them because if you're infected with that virus and you remain untreated, it almost always lead to death. Fortunately if you get bitten, you can get shots and prevent [yourself from] getting sick. But once people get sick with this virus, it's a really nasty one. (From Drew in Mrs. Kerr's class in Boise)

7: Why isn't there a cure for the common cold?

One of the major reasons why there isn't a real cure for the cold is that there are a large number of different types of viruses that actually cause what we call the common cold. The most common one goes by the name of rhinovirus, but there are many other types of viruses that do cause a cold. When rhinoviruses infect a cell, they cause errors when they copy themselves; and when they leave the cell they actually leave a little bit different than when they entered. That means your body has a difficult time remembering or recognizing that virus or the different virus. Viruses are constantly changing, so our body's immune system doesn't have a very good memory for each version of the rhinovirus. These viruses don't really cause an incredibly substantial infection, so we don't have a tendency to remember those as well so we can get sick all over again. (From Corey)

8: How were viruses discovered?

People knew of diseases that were caused by viruses for many hundreds of years, all the way back to when small pox was identified as a disease. Viruses were first identified in the late 1800s. Two people were looking at a virus that was infecting a tobacco plant. They found that if you tried to filter a solution that came from that plant, you could still infect another plant and cause it to get the same disease. We are able to show that, first of all, bacteria can be filtered and eliminated, but that viruses can actually get through that filter. That simple experiment allowed us to first know that there was something now called a virus, known as the tobacco mosaic virus, that infects a plant. The word "virus" is a Latin word for poison. (From Miranda in Pullman)

9: How does a virus make you sick?

Some viruses will actually cause damage to your own cells, which leads to illnesses like influenza, the flu virus. Other reasons why you end up feeling sick when you have a viral infection are because your body is trying to defend itself against the invading virus with symptoms like a fever, a runny nose, a cough and such. Those symptoms are actually a good thing because it's your body's way of trying to get rid of that virus and make you healthy again. (From Savannah and Brandon in Mrs. Hager's third grade class in Grangeville)

10: How does a virus get into your body?

They can come in through the nose or mouth, or sometimes through breaks in the skin, such as a mosquito bite. For most of us, it's through the mouth or even through rubbing your eyes. Also, viruses can get inside you when you breathe them in or by ingesting them when you eat food that's been improperly handled. Viruses like those soft surfaces and they can burrow in that way. (From Colton, Hugo, and Joe in Cathy Rankin's class)

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