What causes scabies mites? - briefly
«Sarcoptes scabiei», the microscopic arthropod, spreads mainly through prolonged skin‑to‑skin contact or sharing contaminated clothing and bedding. Infestation arises when female mites burrow into the epidermis to deposit eggs, producing the characteristic rash.
What causes scabies mites? - in detail
The infestation originates from the microscopic ectoparasite «Sarcoptes scabiei» var. hominis, which penetrates the outer skin layer and creates tunnels for feeding and reproduction.
Transmission occurs through prolonged direct skin‑to‑skin contact, including sexual interaction, familial caregiving, and close contact in schools, prisons, or nursing homes. Indirect spread is possible via clothing, bedding, or towels that have recently housed the parasite; the mite can survive off the human body for 24–36 hours under favorable conditions.
Risk factors that amplify exposure include overcrowded housing, limited access to washing facilities, compromised immune status, and extreme ages (infants and the elderly). Institutional environments where individuals share limited space and resources further increase the probability of transmission.
The mite’s life cycle consists of egg, six-legged larva, eight-legged nymph, and adult stages. Eggs hatch within 3–4 days; larvae emerge, migrate to the skin surface, and develop into nymphs after 2–3 days. Adults appear after an additional 3–4 days, each female producing 10–30 eggs during a lifespan of 4–6 weeks, thereby sustaining the population on a single host.
Environmental temperature and humidity influence survival outside the host; warm (20–30 °C) and humid (≥70 % relative humidity) settings prolong viability, whereas low humidity accelerates desiccation.
Key contributors to mite proliferation:
- Direct, sustained skin contact
- Contaminated personal items and linens
- High‑density living conditions
- Impaired host immunity
- Favorable ambient temperature and humidity
Understanding these elements clarifies the mechanisms behind the spread of scabies mites and informs effective prevention and control measures.