Columns

2017.10.25 Old: We're all friendly hosts

What a fool. I decide to repeat this column from 20 years ago and already my head is itching. 

By DAVID GREEN

I’ve been itching a lot more ever since the Observer’s lice report was published two weeks ago. There have been times recently when I was convinced I had head lice, but I’ve mostly forgotten about them lately. Until now. Just thinking about them increases the urge to scratch.

But I think it’s going to get a lot worse. I just heard a report about some of the other bugs that live on us humans. Those head lice that crop up in school every now and then don’t affect most of us, but there are plenty of other bugs that call us home all the time. You can’t get rid of them; they’re just part of us. Permanent resident status.

Don’t go looking for them. They’re far too small. Just try to get comfortable with the notion that they’re living contented lives all over you.

Take face mites, for example. They love eyebrows. They seek out a cozy hair follicle, that small cavity at the base of a hair, and they call it home. They’re satisfied to hunker down in their own little cave to do all the things you enjoy doing—eating, reproducing...I guess that about covers it.

Follicle mites look sort of like a skinny mosquito with short legs. They enjoy dining on flakes of dead skin and they’re pleased to gulp down the nutritious fluids that ooze up from the surface.

Stop itching. You can’t feel them at all. And stop worrying. They don’t harm you at all. As long as you’re healthy, they’re healthy.

I learned all this stuff from a radio interview with Roger Knutson, the author of “Furtive Fauna: a field guide to creatures that live on you.” You probably know him from his other book, “Flattened Fauna: a field guide to common animals of roads, streets and highways.”

The human body provides an incredible habitat for insects, Knutson says. Think of all the different climates. There are the chilly regions found at the end of fingers. There are the desert regions of the fingernails themselves. Imagine a tiny mite trapped on your fingernail, making its way across that hostile, dry environment without any food or water.

We also have hairy, tropical climates: moist, warmth, shade. There’s something for everyone on the friendly human body.

Different environments harbor different beasts. Head lice need hairs about a millimeter apart. That way they can grasp a couple hairs at a time and hold on. Crab lice are burlier, wider shouldered, and muscular-looking. They do well with hair not quite so tightly packed, maybe about two millimeters apart.

And what do these beasts look like? Suppose they were the size of humans; what would we see?

“I’m awfully glad they’re as small as they are and I am as large as I am,” Knutson said.

To become their size would bring terror beyond your wildest imagination. Triangular shaped. Wide at the front, narrowing toward the back. Enormous lobster-like claws on the front set of legs. Horrifying.

“Nobody would want to encounter a crab louse in a dark alley,” Knutson said. “They’re kind of a nightmare creature.”

Fortunately, that’s not the way it is. We can’t see them. They can’t see us, at least not as a whole. They just occupy a small part of the landscape that is us.

Besides, they’re friendly little guys. Think of them more as cows than as tigers. They’re all grazers. There’s not a predator among them. They wouldn’t hurt a flea. Of course not; a flea would appear like a giant to them. 

So don’t even worry about this concept of humans as the perfect host, as the dining tables to thousands of tiny creatures trying to get under your skin.

And don’t even start to think about some of Knutson’s other creatures, such as teeth amoebas inhabiting everyone’s mouth. Just follow me. I’m heading for the shower, then I’ll be dipping my toothbrush into bleach.