What mite species causes scabies in humans?

The mite species that causes scabies in humans is Sarcoptes scabiei.

Human scabies is associated specifically with Sarcoptes scabiei var. hominis, a human-adapted variety of the broader species Sarcoptes scabiei. Fertilized female mites burrow into the outermost layer of skin, the stratum corneum, where they create winding tunnels and lay eggs. The resulting immune reaction produces intense itching and a rash, often worse at night.

The mite’s life cycle includes egg, larva, nymph, and adult stages. Eggs generally hatch within a few days, and the developing mites mature on or in the skin. Although an infestation may involve relatively few mites, the body’s response to mites, eggs, and fecal material can cause severe symptoms.

Scabies spreads mainly through prolonged skin-to-skin contact, especially in crowded households or institutions. It is not the same as eczema or an ordinary allergic rash, although it can resemble both. Sarcoptes scabiei also infests other mammals, where it causes forms of sarcoptic mange; those animal varieties usually do not maintain a lasting human infestation. In 1687, Giovanni Cosimo Bonomo and Diacinto Cestoni identified the itch mite as the cause of scabies, an early milestone in medical microbiology.