Health & wellness

G force

He finds viruses captivating

Ben Stechschulte

“A lot of our major health problems involve viruses that didn’t make people sick all that long ago,” said Carl Zimmer, a science writer who is author of “Planet of Viruses.” “If you went back a century, there was no HIV.”


Carl Zimmer


Zimmer, a science writer who is author of ‘‘Planet of Viruses,’’ will introduce the Coolidge Corner Theatre’s showing of the science fiction film ‘‘12 Monkeys’’ tonight at 7.


Q. What fascinates you about viruses?

A. Viruses in a way really rule the world, we just don’t know it. They’re the most abundant form of life by far. They’re everywhere: they’re in the oceans, they’re in the soil, they’re in the air, they’re inside of us - even when we’re healthy. And they’ve been around since the beginning of life. Their existence and ours are really intertwined.

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Q. How many are in our bodies?

A. By one estimate, there are 4 trillion viruses in your body. They’re mostly viruses that infect the bacteria that are also living inside of you. They’re kind of like predators in your ecosystem - they are keeping different species in check. We also have viruses in our own genome, which is pretty mind-blowing. There are maybe 100,000 pieces of our DNA that came from viruses.

Q. And there are some we can’t live without?


A. There’s a virus gene that makes a protein that is essential for placentas to attach to the uterus wall. If that gene is not there, there’s no way the placenta can form. So, it’s literally true that none of us would be here without this in our genome.

Q. Of course, viruses make us sick, too.

A. A lot of our major health problems involve viruses that didn’t make people sick all that long ago. If you went back a century, there was no HIV [the virus that causes AIDS]. What a lot of scientists are doing is trying to find a way to predict what is the next virus that is going to jump from animals to us?

Q. Has your research into viruses made you paranoid about them?

A. I don’t think I’m paranoid. Sometimes I feel very fatalistic. Sometimes you just think oh, gosh, something like the movie “12 Monkeys’’ - you start to think, maybe that could happen. I think that one’s a little extreme, but still, there’s some serious trouble ahead, I’m sure.

Q. A lot of people seem to confuse viruses and bacteria. Can you explain the difference.

A. Bacteria are a lot more like us - they’ve got lots of DNA in them, lots of proteins inside of them. They can feed, they can grow, they can divide. Most viruses are just protein cells with just a few genes inside. All they can do is insert their genes and proteins into a cell and force that cell to make new viruses. They’re not quite alive in the sense that bacteria or we are alive.

‘A lot of our major health problems involve viruses that didn’t make people sick all that long ago. If you went back a century, there was no HIV.’

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Q. That’s why they’re harder to treat with medications?

A. There aren’t many good antivirals. There’s not one for the cold. Viruses change quickly - they mutate a lot. If you get sick with a cold, your body starts producing lots of new cold viruses. Every single spot in the cold viruses’ genes may mutate. You’re producing millions or billions of viruses. That means there’s this fantastic opportunity to evolve protection against the drugs we try to make for them. It also means that drugs that work against one strain may not work against another strain. There aren’t a whole lot of targets to hit on a virus.

Q. But scientists are getting better at fighting viruses?

A. I think there’s reason to be optimistic. It’s possible that scientists may need to rethink how they attack viruses to really come up with an effective, new generation of antivirals, but there are people who are exploring that now.

This interview has been edited and condensed. Karen Weintraub can be reached at
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