Sarcoptes Scabiei - Life-cycle

Life-cycle

The scabies mite Sarcoptes scabiei var. hominis goes through four stages in its lifecycle: egg, larva, nymph, and adult.

Upon infesting a human host, the adult female burrows into the skin, where she deposits 2-3 eggs per day. These oval eggs are 0.1–0.15 millimetre (0.0039–0.0059 in) long and hatch as larvae in 3–4 days. Upon hatching, the 6-legged larvae migrate to the skin surface and then burrow into molting pouches (these are shorter and smaller than the adult burrows). After 3–4 days, the larvae molt, turning into 8-legged nymphs. This form molts a second time into slightly larger nymphs, before a final molt into adult mites. Adult mites then mate when the male penetrates the molting pouch of the female. Mating occurs only once, as that one event leaves the female fertile for the rest of her life (1–2 months). The impregnated female then leaves the molting pouch in search of a suitable location for a permanent burrow. Once a site is found, the female creates her characteristic S-shaped burrow, laying eggs in the process. The female will continue lengthening her burrow and laying eggs for the duration of her life.