Sorry, but it’s a fact.
We live surrounded in filth. All humans shed about 5-10 grams of dead skin each
week. About 80% of the material seen floating in a sunbeam are actually flakes of skin.
House dust mites are nearly universal in occurrence - a typical bed mattress may
contain anything from 100,000 to 10 million mites. Ten percent of the weight of a two year old pillow
may be composed of dead mites and their droppings. Carpets and household upholstery also support high
mite populations. What do house dust mites eat? Human and animal skin flakes (Dermatophagoides -
“skin eater”). So, in some ways house dust mites are a good thing - they help stop us from
drowning in our own filth. House dust mites are 0.2-0.3 mm long and translucent. Because of this, they
are essentially invisible to the unaided eye. A dust mite’s tough, translucent cuticle has deep
striations that can be seen from both the dorsal and ventral views, with long setae (hairs) extending
from the outer margins of the body, and shorter setae on the rest of the body. They have eight legs,
no eyes, no antennae, and mouthparts in front of their bodies (resembling a head).
So why are we interested in dust mites?
House dust is a strongly allergenic material because it is usually heavily
contaminated with the fecal pellets and skins of Dermatophagoides. Some estimates are that dust mite
allergens may be a factor in 50-80% of asthma cases, as well as in eczema, hay fever and other
allergic conditions. Exposure of the skin or respiratory tract to proteinases is frequently associated
with allergic sensitization. The wheeze-inducing proteins are digestive juices from the mite gut, which
are quite potent. Exposure to the mites in the first, crucial year of life can trigger a lifelong
allergy. There is no cure, only prevention - controlling house dust mite populations - focusing on dust
control, to reduce the concentration of dust-borne allergens in the living environment by controlling
both allergen production and the dust which transports it.
- No pesticides are currently approved for control of house dust mites.
- Replace feather and down pillows with synthetic fillings.
- Enclose the mattress top and sides with a plastic cover, thoroughly vacuuming mattress pillows and
the base of the bed. Dampen and wipe the plastic mattress cover daily.
- Change and wash pillowcases, sheets, and under blankets, and vacuum the bed base and around the
covered mattress weekly.
- Use nylon blankets rather than wool or cotton ones.
- Frequently wash all bedding (blankets, mattress pads and comforters) in hot water (140 degrees)
weekly. Also wash curtains.
- Replace carpets with wood, tile, linoleum or vinyl floor coverings (vacuum carpets every day).
- Professionally remove acoustic ceilings usually found in older homes, commonly referred to as
“popcorn” or “cottage cheese” ceilings.
- With conventional vacuum cleaners, frequent vacuuming as a dust control measure may aggravate
allergic asthmatic conditions, because they are inefficient. Dust collection by conventional vacuums
can result in a significant increase in airborne dust concentrations. Vacuuming should be done by
using cleaners with additional filtration (such as HEPA filters), or by using equipment that traps
dust in a liquid medium such as water, rather than in a dust bag.
To be effective, measures may need to be taken in order to reduce the house dust mite pollution 10 to
100-fold, something not easily achieved in practical terms. Keep in mind, it’s important not to
become so obsessed with mites, germs and dirt that normal life is impossible.