Cheyletiella blakei, an ectoparasite of cats, as cause of cryptic arthropod infestations affecting humans.

Cheyletiella blakei, an ectoparasitic mite of domestic cats, can cause an extremely annoying, persistent and pruritic dermatosis of obscure origin (cryptic infestation) in susceptible persons having close contact with infested cats. Although the prevalence of cheyletiellosis in humans and cats appears to be low, evidence of its occurrence in California is increasing. Cheyletiellosis is often underdiagnosed in both its natural host and in humans. The small size of the mite, lack of publicity about the disease, frequent absence of symptoms in infested cats and failure to recover the mite from humans contribute to its delayed recognition. When C blakei or other mites are suspected of being the cause of a dermatosis, medical entomologists may help to hasten the diagnosis by examining the patient's physical surroundings, potential vertebrate hosts and other sources for the presence of mites. After C blakei has been eliminated from cats with an appropriate pesticide, the disease in humans is self-limiting.