Ectoparasite Evaluation

Parasite / Transmission Route / Diagnostics
Cheyletiella
Zoonotic / •Ingest: keratin debris and tissue fluid
•Location: skin
•Transmission: direct contact and contact through inanimate objects
•Life cycle: 18–21 days / •Scrape margins of lesions, flea comb, visual, or cellophane tape
•Adult: Body shape resembles a shield or acorn, hook-like accessory mouth parts and comblike structures at the tip of each leg.
Ctenocephalides canis/felis / •Ingest: blood
•Location: head and base of tail
•Transmission: direct contact or through contact with inanimate objects
•Life cycle: 21 days–1 year / •Visual and flea comb
•Adult: medium brown to mahogany in color, laterally flattened body, 2–8 mm long with pronotal and genal combs
•Transmit Dipylidium and Hemobartonella spp.
Cuterebra / •Ingest: N/A
•Location: face and neck region, can be found on any furred area
•Transmission: contact with rodent burrow or eggs from an adult fly
•Life cycle: 3–4 weeks / •Visual
Larvae
•Second stage: cream to white, toothlike spines and 5–10 mm long
•Thirdstage: large, coal black, heavily spined, and up to 3 cm long
Demodex canis / •Ingest: unknown
•Location: hair follicles and sebaceous glands
•Transmission: direct contact from dam to pup; otherwise not contagious between hosts
•Life cycle: 21 days / •Deep skin scrapings on squeezed skin or biopsy
•Adult: cigar-shaped, eight stubby legs at the anterior end of the body, and ¼ cm long
Dermacentor variabilis/andersoni / •Ingest: blood
•Location: whole body
•Transmission: contact
•Life cycle: 3 months–2 years
•Tick must be attached for 5–20 hours to transmit disease. / •Visual
•Adults: blue-gray with white markings on shield
Linognathus setosus / •Ingest: blood
•Location: whole body
•Transmission: contact
•Life cycle: 3–4 weeks
•Definitive host: canine and feline / •Visual
•Adult: dorsoventrally flattened, red to gray in color, head is more narrow than the widest part of the thorax, and first pair of claws smaller than second and third pairs
Otodectes cynotis / •Ingest: epidermal debris
•Location: ear and base of tail
•Transmission: contact
•Life cycle: 18–21 days / •Visual or ear swab
•Adult: oval with eight legs, fused head and thorax, short unjointed pedicel with suckers on the end of some of the legs
Rhipicephalus sanguineus / •Ingest: blood
•Location: whole body
•Transmission: contact
•Life cycle: 6 weeks–1 year / •Visual
•Adult: brown with prominent lateral extensions on head, giving a hexagonal appearance
Sarcoptes scabiei canis
Zoonotic / •Ingest: interstitial fluid
•Location: ears, lateral elbows, and ventral abdomen
•Transmission: contact
•Life cycle: 2–3 weeks / •Deep skin scraping
•Adults: oval with eight legs, fused head and thorax, long unjointed pedicel with suckers on the end of some of the legs
Trichodectes canis / •Ingest: skin and hair
•Location: whole body
•Transmission: contact
•Life cycle: 3–4 weeks / •Visual
•Adult: dorsoventrally flattened, yellow, large rounded head; head is wider than any other part of the body, 2–4 mm

© 2014 John Wiley & Sons, Inc. Published 2014 by John Wiley & Sons, Inc.