vmp 930 veterinary parasitology · sarcoptes scabiei- scabies mite (dogs, pigs, man, sheep, goats,...
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Arthropods Largest, Most Diverse Animal Phylum Jointed appendages Chitinous Exoskeleton Important Parasitic Groups
Arachnids cephalothorax + abdomen + 8 legs Simple Metamorphosis (Hemimetabolous)
Egg, larvae, nymph, adult (all similar in appearance)
Insects Head, thorax, abdomen + 6 legs Simple Metamorphosis (Hemimetabolous) OR
Egg, nymph, adult (all similar in appearance)
Complex Metamorphosis (Holometabolous) Egg, larvae, pupae, adult (are not similar in appearance)
Arachnids General Arthropod Characteristics Cephalothorax + abdomen + 8 legs Simple Metamorphosis (Hemimetabolous)
Egg, larvae, nymph, adult Groups of Parasitic Arachnids (Subclass Acari)
Mites Mesostigmatid mites -- Dermanyssus, Ornithonyssus Astigmatid mites -- Sarcoptes, Notoedres, Otodectes Prostigmatid mites -- Demodex
Ticks Metastigmatid
Argasid – Soft ticks Ixodid – Hard ticks
Mesostigmatid Mites Stigmata (respiratory pores) in the
middle of their bodies
Dermanyssus and Ornithonyssus bloodsucking mites
Mites hide in environment during daytime, feed on birds during night
Blood loss leads to decreased production Heavy infestations may cause death
Control with environmental acaricides, as well as treating birds
Dermanyssus gallinaeRoost mite or Red mite
Spends most of time on birds Decreased production, feed conversion Matted feathers, esp. around vent Treat birds, environment Carried on fomites (egg crates, clothing, etc.) May feed on other hosts (horses, dogs,
man if birds unavailable)
Ornithonyssus sylviarumNorthern Fowl Mite
Astigmatid mites
Lack stigmata - respiration is through integument
Includes the ‘Mange’ mites Family Sarcoptidae
Sarcoptes scabiei - scabies mite (dogs, pigs, man, sheep, goats, cattle, horses) –
different subspecies for various hosts Notoedries cati - cat mange
S. scabiei & N. cati Entire life cycle on host in burrows in skin -
transmission via direct contact Pathology includes skin lesions, secondary infection,
irritation
Mange mites
Treat with topicals: Selamectin (Revolution®)
Imidacloprid + Moxidectin (Advanatge multi®) is most often used
Bath topicals lime-sulfur, carbaryl, malathion, carbamates (not
kittens/puppies), organophosphates (caution with cats)
Systemics Ivermectin - subcutaneous injection In-feed ivermectin for confinement-reared pigs
Sarcoptes & Notoedres
Scaly leg mite of birds(not on exam)
Knemidokoptes mutans Production birds and pet birds Burrow into epidermis of legs causing
scales to lift up, legs become thickened and deformed
Treat with topical acaracides, also oral or IM ivermectin (0.2mg/kg) or 50% topical
Cover affected area with Petroleum Jelly
Otodectes spp.Ear mites (cat, dog, rabbit)
Copious cerumen production mites observed on swabs of ear canal
swab ear with cotton swab and place under warm light
Also visualize with an otoscope
Prostigmatid mites
Stigmata (respiratory pores) in anterior of their bodies
Includes the Follicle mites Family Demodicidae
Demodicidae: Demodex spp.
Demodex canis -- red mange
Demodex cati
Demodex bovis - cattle follicular mite Normal fauna, but if disease
develops (nodules on neck and forequarters); then usually incurable
Demodex folliculorum , D. brevis -- humans
Demodex canis -- red mange
Mites live in hair follicles and sebaceous glands
Red mange --Inflammation and scab formation
Types of Demodectic mange
Localized demodicosis face, skull, ear canal, forelegs, trunk alopecia, scaling, hyperpigmentation,
erythema Dz of young dogs
most resolve spontaneously ~ 10% progress to generalized demodicosis
Generalized Demodicosis large areas of body involved erythema, crusting, rancid seborrhea,
lymphadenopathy inherited immune defect chronic DZ
Demodectic Pododermatitis digital and interdigital disease
Types of Demodectic mange
Demodex canis: Diagnosis Diagnose and monitor using deep skin
scrapings, trichogram (plucked), biopsy
Photos - Mueller et al, 2012
Demodex canis: risk factors
Immune suppression, malnutrition, neoplasia and chemotherapy, endocrine disease Especially with adult-onset demodicosis – cure
immunosuppressive issue and demodicosis should resolve.
Genetic connection to Generalized Demodicosis Part of normal flora but affected adult dogs should
not be bred
Topical moxidectin (weekly) Daily oral milbemycin, moxidectin or ivermectin Amitraz rinses (weekly or biweekly) Topical or oral antibiotics for pyoderma
Monitor treatment success with skin scraping Continue treatment 4-8 weeks post-remission
Clinical cure w/o Parasitic cure = recurrence Neuter dogs with Generalized Demodicosis
Demodex canis: Treatment