Barrier fabrics Temperature control

Public Health Significance of Urban Pests 111

3.3.6.4. Barrier fabrics

Barrier bedding materials can be a major benefit in combating HDMs. They can act as a physical barrier to the mites themselves; on a new mattress, the barrier prevents mites from entering and therefore colonizing it. Also, the barrier stops mite faecal material already present in an old mattress from escaping into the atmosphere, where it can be inhaled. Fabrics with a pore size of 10 µm or less can effectively block the faecal pellets Vaughan et al., 1999. In addition, these fabrics prevent the dead skin cells upon which the mites feed from penetrating the mattress. Thus, the mites and their allergens are effectively contained within the mattress, and the mites are cut off from a continuing food supply. A number of trials of barrier bedding have highlighted the clinical benefits of this type of intervention. As a result of its use, atopic infants who received barrier bedding did not become sensitized to HDM allergens Nishioka, Yasueda Saito, 1998. Also, airway hyperresponsiveness improved significantly after six months with barrier bedding in place van der Heide et al., 1997, and symptom scores in patients with barrier bedding improved after a year. Barrier fabrics should be fitted not only to mattresses, but also to pillows and duvets. It is also essential that barrier fabrics be properly constructed. An effective fabric can lose a significant amount of its efficacy as a result of poor quality zippers and stitching, which can let through allergens. It is also recommended that zippers be covered with flaps and that the barrier provides 100 cover. Moreover, it is important to select a breathable fabric, to prevent the risk of mould growing within the mattress and to minimize dis- comfort from sweating; in general, woven fabrics are longer lasting than other types. For barrier fabrics to be effective, it is also essential for them to be properly cleaned and for the rest of the bedding to be washed regularly, so that it remains free of allergens.

3.3.7. Pesticides