They Mite be Giants

The thought of small little animals running around our face cause most people to squirm a bit. As much as I do like the small animals like spiders and beetles, if I think I feel one crawling on my face I’ll very quickly try to brush it off. It’s not them, it’s me.

Now we are going to get into the stuff that makes me squirm. There’s a great skit from Kids in the Hall about the joke of saying – “Hey, there’s a spider on your back!

In the skit, it starts out as an author writing a book called Hey, There’s a Spider on Your Back, which consist of only that line. And every time anyone reads it they think there is a spider on their back. This makes it a best seller and leads to the audio book. But there really are arachnids on your face. Right Now! There are face mites. Like all arachnids they have 8 legs. Different species of mites live in your hair follicles (Demodex folliculorum) and in your sebaceous glands (Demodex brevis), where oil comes out. And at night, after you go to sleep, they come out, mate, and lay their eggs on your face. Are you squirming now? And the next thing you’re trying very hard not to think about is what happens when they poop? Well there you can rest a little easier. They don’t excrete waste the same way we do. They hold it in till they die and then it decays in their body.

You might be wondering why we study these things. Well first off we don’t know a whole lot about them. We think we know what they eat (dead skin and oils), but we’re not sure. More importantly they can help us learn about human migration patterns. D. brevis is Asian population is genetically distinct from its American cousin. But D. folliculorum is the same in both populations.

And that’s just what’s living on the outside of us. Inside we are a fully ecosystem of predators, prey, and parasites. And they’re important to our health. Come join us on November 9 for a lecture on More than Genes: Predators, Parasites and Partners of the Human Body by Dr. Robert Dunn sponsored by the Leakey Foundation. Dr. Dunn is a biologist with the Department of Biology at North Carolina State University.

Dead skin, sweat, and DUST MITES!!!

Le Déjeuner sur l'herbe
Creative Commons License photo credit: Banalities

I’m sure most of you have seen the commercial, I believe by Mattress Firm, where two men are replacing a woman’s mattress. They tell her that she should replace her mattress every 8 years because after that long, it doubles in weight from all of the dead skin, sweat, and dust mites. She them repeats, in a disgusted and frightened tone, DUST MITES?? That commercial drives me crazy because like any normal Entomologist I think, dead skin and sweat, eww gross!! I’m certainly not grossed out by the thought of dust mites.  They are, after all, decomposers that feed on things like dead skin cells. That might make you cringe, but they are basically little cleaning machines, like all decomposers. So I was wondering what would make people more upset about dust mites than they are about dead skin and sweat. SoI found out!

First a little bit about dust mites. The house dust mite is an arachnid, like all mites, that belongs to the order Acari. Acari also includes ticks. Mites are a very successful and diverse group of animals with about 42,000 species found all over the world. They can be parasites, predators, herbivores, detritivores, or decomposers. Unfortunately for them, many are considered to be pests on plants, animals, humans, and especially in the home, such as dust mites. House Dust mites (Dermatophagoides spp.) are very tiny, but visble without a microscope. The adults are typically about .4 millimeters in length. They are common in most households and feed off of organic debris, human skin cells and animal dander, which is what dust is mostly made up of, hence the name. For this reason, they are mostly found in places like beds, carpet, and other soft pieces of furniture.  They cause no harm to us and would go largely unnoticed if it weren’t for one thing. They are animals and when animals feed, they have to defecate.

The fecal matter of dust mites is highly allergenic due to some of the enzymes within it. Therein lies the problem. Many people have allergies ranging from annoying to severe and sometimes these allergies can induce asthma. Some of these chemicals are also present on partially digested pieces of dust. Most of these allergies can be treated with over-the-counter anti-histamines, but in more severe cases, a game plan may be needed. The idea, as with any pest, is to reduce harborage, or make it a less pleasant place to be. Wood or other hard floors are always a better choice than carpet because they are easier to clean thoroughly and dust mites cannot thrive in/on them. All soft furniture and bedding should be washed regularly. Ten minutes in a hot dryer is enough to kill all stages of dust mites because they are very sensitive to dessication, so the hot dry conditions in the dryer are lethal. Just like with any other pest, removal of clutter, dirt, and food sources usually does the trick. At least once a week, you should dust, vaccuum, wash all of the bedding and anything else washable. This will lead to a relatively mite-free home. If you do have asthma, there are certain mattresses and types of bedding that are actually mite proof!  If you don’t have allergies to dust mites, you can relax a little. Dust mites have been around for millions of years and are probably on most soft surfaces you come into contact with!  I’ve said before that people should just get used to the idea of tiny organisms crawling around and on us! Most people have microscopic mites living in their hair follicles that feed on dead cells and sebacious, or oil gland secretions. These are known as Demodex folliculorum or face mites. There are thousand of other organisms, but they keep us clean and healthy. Plus, they’re not nearly as gross as dead skin and sweat, eeew!

CW39 did a story on dust mites last night, and they interviewed me! Watch the video below.



Can’t see the video? Click here.