Cheyletiella spp. are surface dwelling mites that are distinguished from other mites by their large palpal claws. Ventral view of a Cheyletiella sp. mite recovered from a cat. The large palpal claws and enlarged gnathosoma seen on the anterior portion are very characteristic of this mite. Cheyletiella sp. do not burrow, but do feed on the lymph and tissue fluids.
An egg of Cheyletiella. All developmental stages of Cheyletiella occur on the host. Eggs are glued to hairs loosely and may be ingested by the host and passed in the feces. Though this mite may live off of the host for up to 10 days, transmission is usually through direct contact between parent and offspring.
Lateral view of Demodex cati recovered from the ear canal of a domestic cat. Though usually non-pathogenic and considered normal cat flora, immune suppression may lead to overpopulation of this mite. The crusting pruritic lesions associated with D. cati demodicosis generally involves the pinnae, eyelids, head, and neck.
A budgie infested with Knemidokoptes, with characteristic scaly proliferative lesions on the non-feathered portions of the face. The burrowing of the mite causes the integument to exude a serous fluid that hardens into a crust. Birds acquire the mites through direct contact with other infested birds or with fomites.
Dorsal view of a species of Psorobia. The most economically important member of the Psorergatidae family is Psorobia ovis. Known as the sheep itch mite, Psorobia ovis infests domestic sheep, causing pruritus, wool loss, dry scruffy skin, and erythema. Merinos are considered to be especially susceptible. Similar to Demodex, Psorobia mites live in hair follicles
Crusted lesion from Psoroptes cuniculi infestation in a goat. Lesions consist of exudative dermatitis and hair loss, often beginning in the ear and spreading to the head and neck. The mites live superficially on the skin surface and are easily collected with a superficial skin scraping or scabs that have been broken apart.