#48: House Dust Mites

Litinsects #48:

Month of Mites, Part 4

One of the most well-known mite species, probably because they live so close to us, is the house dust mite. Just a warning, this one’s super interesting but slightly gross...

Dust mites are microscopically small, 0.2-0.3 mm in size, and have a COSMOPOLITAN distribution. They are found pretty much everywhere humans live

Dust is made up of dead human skin cells and also contains hair, dirt, mold spores, pollen, and other microscopic debris. Dust mites feed primarily on dead skin but don’t worry, they DON‘T BITE humans

As I’m sure you’ve heard by now, our mattresses, pillows, carpets, and upholstered furniture are FULL of both living and dead dust mites. Since they love warmth, darkness, and humidity and because we shed plenty of dead skin cells while we sleep, our beds are pretty much the ideal place for them to live!

Dust mites are well known because they are associated with allergies in about 1-2% of the world population. Humans are not actually allergic to the living mites though, it’s ENZYMES in their “DEBRIS” (non-euphemistically: poop) that causes allergies. When the microscopic droppings (0.01-0.04 mm in size!) in dust become airborne and are inhaled it can cause inflammation in the airways and/or trigger asthma-like symptoms in people

What’s the deal with these allergy-causing enzymes? Dust mite poop actually contains mainly UNDIGESTED FOOD particles along with digestive enzymes that work to continue to digest the food in the feces outside of the body... this way mites can re-eat their excrement later! (I’m very sorry to you all for that image but I had to mention it)

I will end on a positive note, by debunking a “fact” you might have heard floating around the internet: the weight of a mattress doubles after 10 years due to a build-up of dead mites and their droppings. Although, yes, they probably do add a bit of weight over the years, there is absolutely NO EVIDENCE for that drastic an accumulation! Still... you’ve technically never had your bed just to yourself

Fun fact: Traces of dust mites were found on the MIR space station in the late 1990s!

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