Once a human contracts the scabies "human itch" mite, he can be infested indefinitely as long as the condition goes untreated. The egg cycle of a female scabies mite is very short compared to her overall life cycle. Scabies eggs only exist for a short time, after which they hatch and go through two different incarnations before the adult mite is ready to breed and lay more eggs.
The Scabies Mite Finds a Home
All it takes is one impregnated female scabies mite to cause an entire infestation on the human body. Once the female mite finds a suitable habitat on the human host--generally where the folds of the skin touch each other, such as the crooks of the elbow, webbing of the fingers, in between the shoulder blades, and under the breasts--she forms a "burrow," where she begins to lay her eggs.
The First Cycle
Scabies eggs take between three and four days to hatch. Three-legged larvae emerge and make their way to the skin's surface, forming shorter burrows called "moulting pouches." The larval stage lasts between three or four days, after which the mite moults into a four-legged nymph.
The Adult Scabies Arrives
The scabies nymph again moults--this time into an adult mite who is ready to breed. The innocuous male mites linger in shallow pits in the skin, biding their time and feeding off the human host. Once mite finds mate, the newly-impregnated louse creates a new burrow of her own and begins to lay eggs. Scabies mites live anywhere between one and two months, during which time they lay two or three eggs daily. However, only ten per cent of these eggs hatch. Most scabies infections are the result of a minuscule number of female scabies mites.
Scabies mites and their eggs can be effectively eradicated on the human body with use of scabicides containing permethrin or crotamiton. These topical lotions are left on the body for around eight hours, after which they are washed off.
Although scabies cannot lay eggs anywhere else but in their burrow, they can survive for 72 hours without a human host. Even after a human infestation is eradicated, personal items such as linens, clothing and sheets need to be washed in hot water and dried on hot air. Items that cannot be laundered may be stored in plastic containers for a few days.