Skin Feeders: Living with Dust Mites
Source: Australian Geographic
House dust mites (Dermatophagoide) are everywhere, feeding off our skin
TONIGHT, AS YOU SINK wearily into bed, you won’t be alone – even if you’re the only person in the room.
Under your slumbering head, the pillow will teem with potentially thousands of unseen bedmates, feasting on your fallen skin flakes.
The good news is they don’t bite. The bad news is they’ll be procreating, defecating, dying and decomposing in your bedding, couches, carpets and clothes. Essentially, we all spend a good deal of time wallowing in dust-mite filth.
The humble dust mite – the species Dermatophagoides pteronyssinus is most common in Australia – is an arachnid, a relative of spiders and ticks. It’s less than half a millimetre long but what it lacks in size, it makes up for in abundance. The detritus in our old pillows is made up mostly of sloughed skin, but the microscopic dust mites, alive and dead, are also there in their thousands, along with mite dung.
CSIRO entomology researcher Dr Matthew Colloff, author of the book Dust Mites, puts the numbers of dead dust mites (only about 5 per cent are alive) in an average bed at between 100,000 and more than 1 million, depending on conditions. “If you’re above 500 mites per gram of dust, which contains skin scales, organic debris, mould, ash, crumbs and all sorts of things, you’re getting into pretty high mite numbers,” explains Matthew. “The highest ever recorded [level] was about 12,000 per gram. Now, if you make a circle with your thumb and index finger, a gram of dust would fit in there, so imagine 12,000 mites in that kind of space.”
The fact that our skin scales are their main food source means generally, wherever we are, they are, says Dr Peter Dingle, associate professor in health and the environment at Murdoch University’s School of Environmental Science. “We shed literally millions of skin cells every day but they have to be dehydrated and de-fatted by mould,” he explains. “The mites wait for the mould to attack and then they feed on both.”
Read More: Australian Geographic