Psoroptes

Psoroptes is a genus of mites that are obligate ectoparasites. They are commonly known as psoroptic mites and are responsible for a form of mange in various animals. The most well-known species, Psoroptes ovis, infects sheep, cattle, horses, and rabbits, causing severe pruritus and wool or hair loss. Other species may affect other mammals.

These mites reside on the surface of the skin, burrowing only superficially into the epidermis to feed on serum and lymph exuded from the damaged skin. Their life cycle, from egg to adult, is relatively short, typically lasting around three weeks, which allows for rapid population growth within a host. Infestation is characterized by intense itching, leading to self-inflicted trauma from scratching and rubbing. This can result in secondary bacterial infections and significant economic losses in livestock due to reduced productivity and treatment costs.

Diagnosis is usually made by microscopic examination of skin scrapings or wool/hair samples, where the mites and their characteristic long, segmented Haller's organs on the first pair of legs can be identified. Treatment often involves acaricidal dips, pour-ons, or injectables. Environmental decontamination is also crucial to prevent re-infestation. Prevention strategies include quarantine of new animals and regular monitoring of livestock. Psoroptes can also occasionally infest humans, causing a temporary itchy rash known as "scabies rodentium," but human infestation is generally self-limiting once the source animal is treated.