Stop Bed Bugs, Save Your Mattress and Box Spring with Encasings.
The usefulness of covering mattresses and box springs with bed encasings to prevent the introduction of both dust mites (Dermatophagoides farinae) and bed bugs (Cimex lectularius). Melissa Patridge RN, BSN, MBA
Dust mites:
There are two common dust mites, the American house dust mite (Dermatophagoides farinae) and the European house dust mite (D. pteronyssinus). Due to their very small size, these dust mites are not visible to the naked eye. They live in bedding, couches, carpet, stuffed toys and old clothing. Dust mites feed on the dead skin that falls off the bodies of humans and animals and on other organic material found where they live. They pose a simple although annoying problem to humans. Dust mite exposure in humans very commonly produces allergic symptoms such as itchiness, runny nose and eye irritation. The dust mite does not bite, but symptoms occur simply due to either direct contact exposure to the live dust mite, its broken down body parts or excrement.
Dust mites are extremely small in size. We use micron units for such small measurements. Avoidance and cleaning measures including bedding encasement all lead to a reduction in the population of dust mites and usually a satisfactory reduction in symptoms. Medical literature and Allergists agree on these cleaning measures and use medication and immunotherapy regimes for complete treatment. Mattress encasement effectiveness depends on the micron pore size of the fabric to measure smaller in order to filter the dust mite, its excrement, broken down body parts and eggs.
Bed bugs 
The bed bug and its eggs are much larger and are measured in fractions of an inch and more easily seen by the human eye. Bed bug documentation is much less sited in the literature. Currently there is an increase in outbreaks and complaints regarding bed bug infestation. The bed bug is much larger than the dust mite. Its travel worldwide is attributed to its hearty ability to survive on luggage and inanimate objects without food and water. The egg is hearty and able to survive many months. The bed bug and its eggs are susceptible to extreme temperatures and chemical extermination. The bed bug pierces the skin of the host with its sharp beak. It begins feeding and injects oily, odiforous liquid into the skin causing itchiness and swelling. Exterminator services are the first line of defense for bed bug infestations. To save the infested mattress, whether treated or not, any bed encasing (vinyl, waterproof and breatheable fabric) used for protection from the dust mite, its feces and broken down body parts is sufficient for the much larger sized bed bug and its eggs.
Conclusion
Many state and local governments do not allow mattresses to be sprayed with chemicals therefore the infested mattress is thrown away. Encasing the mattress proactively and after bed bug infestation will spare the mattress. The encasing fabrics used for dust mite treatment are more than sufficient due to the larger size of the bed bug compared to the dust mite.
Avoidance and bed encasings are the first line of defense for those with a sensitivity to dust mites. Bed encasings are the second line of defense (after extermination takes place) for prevention of the bed bug re-infestation. The encasing serves the purpose of both containing the bed bugs and eggs within the mattress keeping them from biting humans and later perishing. Additionally the encasing prevents new infestations from spreading to the encased mattress.
References:
Frishman, A. 2000. Bed Bug basics and control measures. Pest Control 68: 24.
Harlan, Harold 2001. Personal Correspondence. NPMA.
Krueger, L. 2000. Don't get bitten by the resurgence of bed bugs. Pest control 68: 58-64.
P. D. Curtis and K. L. Sullivan. 2001. Bats. Wildlife Damage Management Fact Sheet Series.
USDA leaflet number L-453 entitled "How to Control Bed Bugs."
W. S. Cranshaw and F. B. Peairs. 1997. Bat bugs and bed bugs Fact sheet .
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