How is a scabies mite transmitted? - briefly
The mite spreads mainly through prolonged skin‑to‑skin contact; brief contact rarely transmits it. Secondary transmission can occur via contaminated clothing, bedding, or towels.
How is a scabies mite transmitted? - in detail
Scabies results from the ectoparasite Sarcoptes scabiei var. hominis. The mite spreads primarily through uninterrupted skin‑to‑skin contact. Transmission typically requires several minutes of direct contact; brief encounters rarely transfer enough organisms to establish infestation. Household members, sexual partners, and caregivers are most vulnerable because of the sustained proximity.
Key pathways include:
- Direct physical contact: prolonged hugging, sharing a bed, or close caregiving.
- Shared fomites: infested clothing, towels, bedding, or upholstered furniture can harbor viable mites for up to 48 hours under ambient temperature and humidity. Transmission via these items occurs when skin contacts contaminated surfaces shortly after use.
- Crowded environments: prisons, dormitories, nursing homes, and refugee camps facilitate rapid spread because individuals share sleeping quarters and personal items.
- Occupational exposure: health‑care workers, childcare providers, and personal‑service staff may acquire mites through repeated patient or client contact.
Mite survival outside the human host depends on environmental conditions. At 20‑25 °C and 70‑80 % relative humidity, adult females remain active for 24‑48 hours; lower humidity or higher temperatures reduce viability. Eggs and larvae are more sensitive, dying within a few hours when removed from a host.
Factors that increase transmission risk:
- Close, repeated interaction with an infested person.
- Compromised skin integrity (e.g., eczema, dermatitis) that eases mite penetration.
- Immunosuppression, which can prolong infestation and increase mite load.
- Inadequate laundering of clothing and bedding, especially at temperatures below 50 °C.
Effective control relies on interrupting these routes: immediate treatment of all contacts, washing clothing and linens at high temperature or sealing them in plastic for 72 hours, and avoiding shared personal items until therapy is completed.