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47 Cards in this Set
- Front
- Back
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Mites - General Characteristics
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-tiny, most microscopic
-ventral mouthparts -hypostome, if present, not barbed -lack basis capitulum and scutum |
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Mite - possible diagnostic characteristics
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-long setae (hairs) on body or legs
-claws on tarsus -and/or tarsal suckers found -clasping hairs or feathers -burrowing under skin or scales -in hair follicles -in the ear canal, or nasal cavity -somewhat host specific |
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Mites - life cycle
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-egg to egg is app. 3 weeks
-most spend whole life on host -egg-larvae-protonymph-deutonymph-adult -some are nest dwellers, only intermittently on host to feed -transmitted via direct contact -can survive off host 5-20 days in cool/moist env. -many mites more prevalent in cooler climates and during winter |
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Sarcoptidae lesions
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-deep burrowing in skin, tunnels in dermis
-mites in skin -can stimulate extensive lesions -pruritis, thickened skin and secondary infection, alopecia |
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Psoroptidae lesions
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-surface feeding
-abrade skin allowing serum to ooze -mites under scab formed by dermal damage, pruritis |
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Cheyletiellidae lesions
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-dry or moist dermatitis with scaling on dorsum of host
-lesions may be circular -mites on surface |
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Trombiculidae lesions
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-chiggers
-discrete, small red lesions -attaches to skin -often leaves before dermatitis begins |
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Demodicidae lesions
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-live in hair follicles, but not limited to them
-deep in sebaceous glands -alopecia, change in skin color, nodules, secondary bacterial infection |
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Skin scraping
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-superficial for surface mites
-deep scraping & squeezing for Demodex -scrape into dermis for tunneling mites (Sarcoptes) -scrape edge of active lesions, sample different sites -mineral oil will trap mites for direct observation --5-10% KOH or NaOH will dissolve skin hair and scabby material for mite observation |
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Suborder: Mesostigmata
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-Dermanyssus
-Ornithonyssus -Pneumonyssoides -Raillietia -Ophionyssus |
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Suborder: Prostigmata
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-Trombicula
-Demodex -Cheyletiella |
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Suborder: Astigmata
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-Sarcoptes
-Notoedres -Knemidocoptes -Psoroptes -Chorioptes -Otodectes -Lynxacaris |
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Mesostigmata characteristics
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-have a respiratory pore (stigmata) between 3rd/4th coxae
-coxae close together in anterior -tarsi have claws -ventrum with plates -most are nest dwellers |
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Family Dermanyssidae charcteristics
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-mostly predatory mites
-large size -only a few genera are parasitic -four pair of long legs attached anteriorly with coxae close together -nest dweller as well as on host -control req. environmental as well as host treatment |
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Dermanyssus gallinae
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-"red chicken mite"
-cosmopolitan mite of domesticated and wild birds which, under suitable conditions, may feed on mammals such as man -large mite (.75mm) -blood feeders, turn red after a meal -cause anemia and skin irritaiton, decreased production -feeds on host at night, unusual for mites -life cycle-10 days; rapid populations |
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Ornithonyssus sylvarium
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-"northern fowl mite"
-parasites of poultry and other birds in temperate areas -nymphs and adults blood feeders -large mite (1mm) -eggs laid on host, usually around vent -mites found around vent, sometimes rest of body -clinical signs: matted feathers and gray scabby skin around vent -short, 5-7 day life cylce -cause lowered production, anemia and death -dont survive off host for long -rapid population growth = problems in caged layers |
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Ornithonyssus bursa
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-"tropical fowl mite"
-parasites of poultry and other birds in tropical areas -mites are found near vent, beak and eyes -life cycle in nest and on birds; live up to 10 days off host -in poultry, life cycle usually occurs entirely on bird |
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Ornithonyssus bacoti
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-"tropical rat mite"
-cosmo parasite of man and rats -intermittent feeders, breed in nest -life cycle may take 11-16 days -transmits: -murine typhus Rickettsia typhi (rickettsia) -R. akari (rickettsialpox) -Q fever Coxiella burnetii (rickettsia) to humans -spirochetosis (Borrelia anseria) to poultry |
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Pneumonyssus caninum
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-"nasal mite of dogs"
-may be normal inhabitant of nasal cavity, rarely trachea and lungs of dogs -rare -associated with sneezing and head shaking but not common cause of irritation -mite resembles a small tick -highly specific to canids -treat with ivermectin and milbemycin |
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Raillietia auris
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-"cattle ear mite"
-deep in ear canal of cattle -associate with middle ear problem in young suckling calves -rare condition -feed on ear wax/sloughed epidermal cells |
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Ophionyssus natricis
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-blood sucking mite of snakes and lizzards
-large (.6-1.3mm) yellow-brown -live under scales -often feed around mouth/eyes -spend time off host where they oviposit -cause anemia, lethargy and even death -transmit Aeromonas hydrophyla (mouth rot/hemorrhagic septicemia) -also implicated as a vector of incluson body disease of snakes, primarily boids |
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Prostigmata characteristics
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-anterior stigmata present
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Trombiculidae characteristics
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-"chiggers"
-larva of trombiculid mites -over 40 genera found within the continental U.S. -most are yellow to red in color, have 3 pair of legs (larvae) -often body and legs with many setae -salivary enzymes cause local dermatitis in man and other animals -chiggers only feed for hours by the pruritis persists for days -most commonly occur in early spring and fall -local or systemic treatment may relieve itching -easy to kill but damage already done -hypersensitive area easily invaded by secondary bacterial or fungal agents -nymphs and adults free-living |
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Family: Demodicidae characteristics
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-elongate cigar shaped mites with short stubby legs grouped toward anterior
-live in hair follicles and sebaceous glands -common symbiont of most hosts -disease rare, infection common -demodectic mite species are host specific -most disease occurs in dogs but lesions may occur in other hosts -egg-larvae-protonymph-deutonymph-adult -entirely on host, 18-24 days -transmitted direct contact |
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Demodex canis
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-present in virtually all dogs
-only a small % will develop mange -disease is a result of failure to mount an adequate cell-mediated immune response -disease is also associated with concomitant disease of many kinds, i.e. distemper virus, heartworms, ehrlichiosis, etc. immune depressants -direct relationship between # of mites and disease severity |
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Family: Cheyletiellidae characteristics
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-inhabit fur of host and feed on skin debris
-scaly dermatitis, "walking dandruff" -large (250-400 um) shield shaped mite with prominent in-curving palpal claws -most commonly found in environments with many puppies such as breeding kennels and pet stores -considered free living, but cant live long off host -relatively host specific, but crossover occurs and all 3 species may transiently affect humans -no species specific to humans so infestation occurs when handling infested animals |
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Cheyletiellidae species
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-Cheyletiellidae yasguri - dog
-Cheyletiellidae parasitivorax - rabbit -Cheyletiellidae blakei - cat |
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Cheyletiellidae lesions
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-exfoliative:
-scaling process which looks like a bad case of dandruff (walking dandruff) -most of the alopecia and inflammatory changes are secondary to scratching -pruritis varies from moderate to severe -usuall begins along dorsal midline -crustose: -multiple, discrete, circular lesions on the trunk of the body -lesions may enlarge and appear similar to ringworm -this form usually occurs in conjuction with the exfoliative form and may be associated with secondary pyoderma |
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Suborder: Astigmata characteristics
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-no stigmata
-coxae 1/2 widely seperated from coxae 3/4 -no ventral plates -most have tarsi with suckers -most notable: scabies mites |
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Sarcoptes scabiei
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-"sarcoptic mange, scabies, scab"
-populations of mites are indistinguishable among those found on various hosts -can colonize on different species to cause pruritis, but cant breed -host-adapted varieties -entire life cycle on host -round mites -live under keratin layers -triangular shaped spines on dorsal surface -only legs 1/2 extend past body -terminal anus |
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Notoedres cati
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-cat, occasionally rabbits
-starts on head, can become generalized in kittens -very similar to Sarcoptes except anus dorsal, not termianl -few angular dorsal spines on body -burrowing mite requires deep skin scrapings -other Notoedres species in rodents |
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Knemidocoptes mutans
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-"scaly leg mite"
-turkeys and chickens -burrows in skin of feet and legs, swelling of legs, deformation -round mite with 4 very short pair of legs, no tarsal suckers -scab formation, birds may become crippled |
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Knemidocoptes pilae
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-budgerigars at base of beak (cere) and legs
-scaly area proliferation of cere, scaly legs, malformed beak -round mite with 4 very short pair of legs, no tarsal suckers |
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Family: Psoroptidae members
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-Psoroptidae ovis is a body mite of sheep
-Psoroptidae cuniculi is an ear mite of rabbits but will infest ears of other species -Chorioptes bovis -Otodectes cynotis |
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Psoroptidae ovis
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-"sheep scab mite, cattle scab mite"
-eradicated from domesticated U.S. sheep and rare in cattle -feed on skin, lymph exudate from abraded skin forming scabs that grow and coalesce -initially along dorsum, moves ventrally -cool season parasite when hair coat is long enough to prevent self grooming -mid January to March -quarantinable infection in cattle -reportable infestation, treatment under control of regulatory officials -especially seen in western states; problem in crowded conditions; feedlots -causes hair loss, scab formation, wt. loss and death |
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Psoroptidae ovis description
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-body oval
-at least 3 pair of legs extending past body margins -tarsal suckers on long jointed stalks -male: tarsal suckers on legs 1,2 and 3 -female: tarsal suckers on legs 1,2,and 4, long setae on leg 3 -11 day life cycle with increased egg production in winter |
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Psoroptidae cuniculi
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-"ear canker mite (rabbit)"
-ears of goats, horses and rabbits -extensive crusty scab formation in ear canal -in rabbits the entire ear may be involved, honeycomb like exudate may fill ear canal -in horses may see white specks moving in brown exudate -horses may have head sensitivity and become malodorous at base of ears -morphologically similar to P. ovis -not reportable but in aberrant hosts may become a body mite |
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Chorioptes bovis
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-"foot mange mite"
-cattle, horses, goats occasionally sheep -oval mite, short mouthparts, tarsal suckers on short bell stalk -feed on skin, do not burrow -scab formation on feet, legs, scrotum, escutcheon, tail head, may become body mites -scale formation especially feet of horses and sheep -often in draft horse breeds, characterized by foot stomping and greasy heel -usually problem in individuals within a herd, others apparently resistant to mites |
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Otodectes cynotis
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-"ear mites"
-cats, dogs, other carnivores, not particularly host specific -predominantly occurs in the ears, white mites on skin surface of ear canal -oval shaped mite with tarsal suckers on short bell stalk -leg 4 of females very short -feed on epidermal detritus and lymph from abraded skin -pathogen only in ear, however mites can live for "long periods" on other parts of body -tip of tail of cats in preferred area. Important in treating animals to prevent recurrence |
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Lyncacarus radovskyi
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-cat fur mite
-body ellipsoidal and laterally flattened -grasps hair with legs and palps -found over tail and perineal area or over entire body -hair coat may appear scruffy or feel granular -infested hairs easily removed -some cats ehibit pruritis, excessive grooming, hair balls -South Florida, South Texas, Hawaii, Fiji and northern Australia -treat with fipronil, selamectin, ivermectin or milbemycin |
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Family: Dermanyssidae members
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-Dermanyssus gallinae
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Family: Macronyssidae members
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-Ornithonyssus sylvarium
-Ornithonyssus bursa -Ornithonyssus bacoti -Pneumonyssoides caninum -Raillietia auris -Ophionyssus natricis |
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Family: Trombiculidae members
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-Trombicula alfreddugesi
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Family: Demodicidae
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-Demodex
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Family: Cheyletiellidae
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-Cheyletiellidae yasguri
-C. parasitivorax -C. blakei |
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Family: Sarcoptidae
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-Sarcoptes scabiei
-Notoedres cati -Knemidocoptes mutans -K. pilae |
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Family: Psoroptidae
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-Psoroptes ovis
-P. cuniculi -Chorioptes bovis -Otodectes cynotis |
