# Pile of Viruses

What if every virus in the world were collected into one area? How much volume would they take up and what would they look like?

Dave

It would be a huge pile, but human viruses would make up only a tiny fraction of it.

HIV, the virus that causes AIDS, has killed tens of millions of people worldwide, and over 30 million people are currently living with HIV. The number of copies of the virus carried in someone's blood can vary dramatically,[1]Data on viral load—the number of copies of the virus per mL of blood—can be found in this paper. but across all the people in the world, there probably exists about a spoonful worth of HIV.

The typical healthy human body contains about $3 \times 10^{12}$ viruses. This is actually not as many as you might expect; by volume, humans are apparently a less friendly environment for viruses than, say, soil.[2]An area of wetlands in Delaware contains something like four billion viruses per mL of soil, in case you were looking for a fun vacation destination.

If you gathered together all the viruses in all the humans in the world, they would fill about ten oil drums:

These 10 barrels only represent a tiny portion of the global virus community. Most of the world's viruses aren't found in humans. They're found in the sea.

Seawater is full of microorganisms, and we've recently learned that those microorganisms are preyed on by viruses in a big way. Every day, about one in five living cells in the ocean is killed by a virus. These viruses are found from the surface of the ocean down to the depths.[4]Oddly, as you go further offshore and further down, the concentration of viruses doesn't decrease as much as the concentration of bacteria, so the virus-to-bacteria ratio is higher in the deep oceans than near the shore. Because the sea is so big,[5]Citation: Go and look at the sea. It's big. it contains a staggering number of viruses.

If you piled up all these viruses—more than 1030 of them—in one place, they would be the size of a small mountain.

It's hard to say exactly what the virus mountain would look like, but it would probably resemble something in between pus and meat slurry.[6]Blame Dave—he's the one who asked. Regardless of its exact appearance, it would almost certainly be disgusting.

The pile wouldn't stay mountain-shaped for long, any more than a mountain of any organic secretion would.[7]If you don't believe me, try building a mountain of earwax or snot. You'll find you can't make it higher than a few inches before your friends and family show up and sit you down for a talk. To avoid a gigantic flood, it might be better to collect them into some kind of container.

MetLife Stadium, host of Super Bowl XLVIII, has a volume of about 1.5 million cubic meters. Earth's viruses could fill the stadium about 150 times over.

So if you watch the Super Bowl, take a moment to picture all the players floating, suspended, in a sea of yellowish-white secretions.

Enjoy the game!