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 Dust Mite
has 8 legs and is at the same order “Araneae” as spider
in classification. The body of a dust mite is invisible
to the naked eye and can only be viewed under
microscope. A typical dust mite measures about 100- 400
µm in length (almost 0.5 mm) and 300 µm in width. From
recent research, three main kinds of house dust mites
(Dermatophagoides pteronyssinus, Dermatophagoides
farinae and Blomia tropicalis) are being one of the
single greatest sources of allergies and are significant
triggers of asthma attacks. The fecal matter, egg and
the remains of dust mite can cause allergies too. Even
worse, their tiny size enables them to spread fast and
easily in air.
Ideal environment to dust mite
growth – Our home
The warm and humid condition of
Sub-tropical climate offers an ideal environment to dust
mite growth at human home, especially when the
temperature is between 20°C and 30°C; relative humidity
between 60~80%. (In general, the house dust mite cannot
survive when the relative humidity is lower than 55% and
the room temperature higher than about 50°C.) In
nowadays home environment, the centralized heating and
the condensed moisture within a constrained house are
enhancing the good condition to dust mite growth.
The box spring of a double bed can accommodate
up to 2 million no. of mites and several pounds of fecal
matter produced by mites. In other words, people are
spending 1/3 of their lifetime, which is approximately
the sleep time of people, being exposed and direct
contact to dust mite and its allergens.
On
the other hand, dust mites survive and reproduce easily
in bedding (pillows, mattresses, box springs and
comforters) where the essence of mite growth is
provided:
（１）Adequent food - Dust mites feed on
organic detritus such as flakes of shed human
skin
（２）Optimal humidity - humidity generated by the
human body during several hours of breathing and
perspiring
（３）Optimal temperature – heat from human
body
(Dust
Mite)
It is estimated that the weight
of dust mites and their fecal matter in a pillow which
has already been used for 2 years is about 10% of the
weight of the pillow. And one gram of dust may contain
up to 1000 no. of dust mites and 200,000 fecal particles
which are smaller and lighter than dust mite and can be
inhaled more easily. When people are carry daily housing
keeping and moving the bedding, these tiny particles may
easily go into the respiratory system of human, even
enter the primary bronchioles in lungs. As a result,
human allergy symptoms like asthma attacks will be
observed.
As we can see, dust mites survive and
reproduce easily in bedding where optimal growth
condition and food is present – sweating of human during
sleeping and skin cells and flakes shed from man. The
number of dust mite will increase with the service time
of bedding. Therefore encasing the pillows, mattresses,
box springs and comforters by allergen barrier will be
the best way to control our exposure to dust mites and
allergens
Info provided by allergy and asthma expert
forum
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