Arachnid
House Dust Mite
Dermatophagoides pteronyssinus
Biology
House dust mites, primarily Dermatophagoides pteronyssinus (Trouessart) and D. farinae Hughes, are microscopic arachnids (0.2-0.3 mm) in the family Pyroglyphidae. They are nearly invisible to the naked eye. Their bodies are translucent to whitish and oval-shaped, with eight legs. These mites do not bite or burrow into skin; instead, their fecal pellets and shed exoskeletons are potent allergens. The life cycle from egg to adult takes approximately one month, involving larval and two nymphal stages, and adults live for 2-3 months. Females lay up to 80 eggs during their lifespan.
Behaviour
House dust mites thrive in stable environments with high humidity (70-80% RH) and moderate temperatures (20-250C). They feed primarily on shed human and animal skin flakes, supplemented by other organic debris. They absorb water from the atmosphere, making high humidity crucial for their survival. They are negatively phototactic, preferring dark, undisturbed locations within textiles. Reproduction is continuous in suitable conditions, leading to persistent populations in infested dwellings. Their microscopic nature and cryptic habits make their presence often unnoticed until allergic symptoms manifest.
Habits
Dust mites are ubiquitous in human dwellings, commonly found in mattresses, pillows, upholstered furniture, carpets, and bedding—anywhere dead skin cells accumulate and humidity is sufficient. Conducive conditions include poor ventilation, high indoor humidity caused by factors like showering, cooking, or unvented dryers, and the presence of textiles that trap dust and skin flakes. Overly clean homes can still harbor mites if these environmental conditions are met. Their allergens are a major trigger for asthma, allergic rhinitis, and eczema worldwide.
Control methods
- 1Encapsulate mattresses and pillows with mite-proof covers.
- 2Wash bedding weekly in hot water (600C/1400F).
- 3Reduce indoor humidity to below 50% using dehumidifiers.
- 4Remove carpets and upholstered furniture where possible.
- 5Vacuum regularly with a HEPA-filtered vacuum cleaner.
- 6Dust with a damp cloth to prevent allergen dispersal.
Tailored to House Dust Mite
IPM Procedure Checklist
Inspection
- Survey interior and exterior for evidence and conducive conditions
- Document findings with photos and a site map
- Place monitors to confirm activity
Identification
- Confirm House Dust Mite (Dermatophagoides pteronyssinus) — not a look-alike
- Note life stage and risk level: Moderate
- Capture clear photos and samples for the record
Action Thresholds
- Trigger action when monitor counts trend up
- Re-evaluate weekly during active season
- Document trigger criteria in the IPM plan
Prevention
- Exclude entry points and harborage
- Improve sanitation and moisture control
- Modify habitat around the structure
Control Methods
- Encapsulate mattresses and pillows with mite-proof covers.
- Wash bedding weekly in hot water (600C/1400F).
- Reduce indoor humidity to below 50% using dehumidifiers.
- Remove carpets and upholstered furniture where possible.
Monitoring & Evaluation
- Service monitors on schedule and trend captures
- Re-inspect for House Dust Mite activity at follow-up
- Adjust tactics based on data; report findings to client