chapter 42 Sarcoptid Mites.......................................
DEFINITION/OVERVIEW
Nonseasonal, intensely pruritic, highly contagious parasitic skin diseases of dogs and
cats caused by infestation with sarcoptid mites.
ETIOLOGY/PATHOPHYSIOLOGY
Sarcoptes scabieivar.canis: dogs – sarcoptic mange/scabies (Figures 42.1, 42.2).
Notoedres cati:cats – notoedric mange (Figures 42.3, 42.4).
Cheyletiella yasguri: dogs – “walking dandruff” (Figure 42.5).
Cheyletiella blakei:cats – “walking dandruff.”
Otodectes cynotis: dogs and cats – ear mites (Figure 42.6).
Sarcoptes scabieiandNotoedres cati: mites burrow through the stratum corneum and
cause intense pruritus by mechanical irritation, production of irritating by-products,
and secretion of allergenic substances that produce both antibody- and cell-mediated
immune reactions.Cheyletiellaspp.: live in the upper epidermis between follicles; piercing mouthparts
cause mechanical irritation; pruritus significantly increases with development of
hypersensitivity.Otodectes cynotis:do not burrow; entire life cycle occurs within the external ear canal;
feed on epidermal debris; irritation and later development of hypersensitivity cause
accumulation of cerumen and blood within the ear canal; can produce “ectopic”
symptoms at other body sites; associated with 50–80% of otitis externa in cats.Life cycle for all mites may be completed in as few as 21 days.
Mites can transiently affect species other than the host species (dog, cat, fox, rabbit,
human) via direct contact; lack of host specificity may affect treatment requirements.
Considered highly contagious within the host species.
Zoonosis: mites can burrow and survive for limited periods on humans.
SIGNALMENT/HISTORY
Animals of all ages and breeds; most often seen in younger animals.
Exposure to a carrier often 2–6 weeks before development of symptoms.
Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Dermatology, Third Edition.
Karen Helton Rhodes and Alexander H. Werner.
©2018 John Wiley & Sons, Inc. Published 2018 by John Wiley & Sons, Inc.
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