Ca & Fe Mites Flashcards
Which arachnid parasites do we care about?
- Burrowing mites
- surface mites
- ticks (hard & soft)
Defining feature of class arachnida?
8 legged adults
What are the types of burrowing mites?
- Sarcoptes sp
- Notoedres sp
- Demodex sp.
what are the types of surface mites?
- Eutrombicula sp.
- Cheyletiella sp.
- Octodectes sp.
What are the types of ticks?
- HARD (Family Ixodes)
- SOFT (Family Argasidae)
What is the life cycle of mites?
- Adults (8 legs) on host lay eggs on host -> the eggs may not be susceptible to treatment -> eggs hatch into larvae (6 legs) on host -> larvae turn into nymphs (1 & 2; 8 legs) on host -> nymphs turn into adults
- life cycle takes @ least 10-21 days
- Note this does not apply to Eutrombicula (opportunistic & only come onto host as nymphs)
What is the pathogenesis of mite acariasis?
- range from no effects to severe dermatitis (mange)
- hypersensitivity
- excoriation & secondary bacterial infection
What are the defining characteristics of Burrowing mites?
- dorso-ventrally flattened
- short legs
Sarcoptes full name?
Sarcoptes scabei var canis
Sarcoptes host?
- Dogs (mainly host specific)
- highly contagious w/ other dogs, wild canids
- transiently zoonotic (self resolving)
Defining features of Sarcoptes?
- short legs
- long unjointed pedicel
where do Sarcoptes live?
tunnels in the Stratum Corneum
What can Sarcoptes cause and what are the symptoms?
SARCOPTIC MANGE
- hairless areas (ears, elbows, ventrum, tarsal)
- INTENSE pruritus (Hidradenitis suppurativa)
- erythema
- crusts
- hair loss, excoriation
- hyperkeratosis
- +/- MITES
What is the host of Notoedres sp?
CATS
- highly contagious among Fe; transient zoonoses
Defining features of Notoedres cati?
- smaller than Sarcoptes (need to know it came off of a Fe to ID)
- adults do not survive in environment
Notoedres sp symptoms?
- affects ears
- then face, eyelids
- +/- feet & perineum
- intense pruritis
- dry, crusty skin
- hair loss, excoriation
- hyperkeratosis
- lymphadenopathy
What are the demodex spp in Ca?
- D. canis
- D. injai
- D. cornei
What are the demodex spp in Fe?
- D. cati
- D. gatoi
- other Demodex spp
Transmission of Demodex spp?
- part of normal environment of animal
- not zoonotic
- not contagious (except potentially D. gatoi - amongst show cats)
- no environmental survival
- vertical transmission: from close contact w/ dam
Demodex under the microscope?
- eight legs on thorax
- live in hair follicles & sebaceous glands (may need to squeeze to see!)
Is seeing Demodex spp under the microscope clinically significant?
- is the number of adults more than expected?
- is there a lot of larvae and nymphs compared to adults? could mean they are breeding a lot
what is the clinical presentation of demodectic mange in Ca?
- most are asymptomatic (normal fauna)
- can have localized demodicosis, generalized demodicosis (juvenile or adult onset), or pododemodicosis
- generally not pruritic
What is localized demodicosis?
- IN YOUNG DOGS (3-18 MONTHS)
- occurring around mouth, eyes, forelegs, rarely ear canals
- focal alopecia, squamous, silver scaling, not pruritic, self resolving (most self-cure w/in 1-2 months)
What is generalized demodicosis?
- OCCURS AT ANY AGE, PROGNOSIS BETTER FOR YOUNG
- starts on face & limbs
- generalized when > or = 5 lesions
- pustular form
- folliculitis
- hyperkeratosis
- painful, not pruritic unless secondary bacterial infection
- even sepsis, & death
What is pododemodicosis?
- may be a manifestation or sequelae of generalized form
- least common form of disease (usually all 4 paws)
What is demodicosis?
- young animals (3-18 m): localized: excellent prognosis, often self recovery; generalized (family history, purebreds, severe stress): good prognosis w/ treatment
- older animals (> 1.5 yr), generalized form: often underlying immune deficiency, concurrent disease, reproductive stress (heat cycles); poor prognosis, difficult to treat (60-80% cure rate)
- isoxazolines, moxidectin/imidacloprid
- antibiotics, nutritional support, grooming
- do not use parents or pups for breeding
What is feline demodicosis?
- RARE
- D. cati: eyelids, head, neck (localized often resolves spontaneously; generalized check for underlying disease (FLV, FIV) or after being put on an immune suppressing medication like prednisone)
- D. gatoi: pruritic, contagious (often no underlying disease; in show & pedigree Fe)
what are the defining characteristics of surface mites?
- dorso-ventrally flattened
- long legs
What are the hosts of Cheyletiella yasguri?
DOGS
What are the hosts of Cheyletiella blakei?
CATS
What are the hosts of Cheyletiella parasitivorax?
RABBITS
- most common
How contagious are Cheyletiella spp. in general?
- contagious w/in & among spp
- zoonotic
Identifying features of Cheyletiella spp adults?
- palpal claws
How well do Cheyletiella spp. survive in the environment?
may survive in cool environment for > 10 days
Clinical signs of Cheyletiella spp?
- often subclinical
- starts as dorsal scaling
- +/- MILD pruritis, hair loss
- rarely: hypersensitivity, miliary dermatitis, dorsal hypotrichosis
What are the hosts of Otodectes cynotis?
CATS, dogs
- 50% of otitis cases in cats is due to ear mites
- < 10% of otitis cases in dogs is due to ear mites
- highly contagious, usually not zoonotic (transient zoonotic infections do occur)
How well does Otodectes spp survive in the environment?
- adults can survive in cool, humid environments for months
Symptoms of Otodectes spp?
- not always restricted to ears (can be systemic)
- pruritis, head shaking, behavioural disturbances (hypersensitivity)
- worse in young & immunocompromised
What do Eutrombicula spp do?
- FREE LIVING MITES
- ONLY LARVAE ARE PARASITIC (6 legs) - wide range of hosts
- zoonotic (but from environment, not host to host)
defining characteristics of Eutrombicula spp?
- 6 legs (larvae)!
- plumose (feathery) setae
Symptoms of Eutrombicula spp?
- occur on head, ears, around eyes, feet (btwn toes), ventrum (inguinal)
- can be mild to severe pruritis associated w/ stylostome (feeding tube that they leave behind)
- infestation is transient
How do we diagnose mites?
- history & clinical appearance
- sample outside of the lesions
- burrowing mites: multiple samples, deep skin scrapings +/- potassium hydroxide (KOH) digest; biopsy can also work)
- surface mites: tape, comb, vacuum, hand lens, fecal (in Fe b/c of how they groom themselves -> ingestion)
- ear/nose mites: otoscopy/rhinoscopy & swab (mineral oil)
- interpret results (remember: is a few demodex a concern? what about a ton of nymphs & larvae?)
How do we treat mites?
- macrocyclic lactones (oral, topical, parenteral): ivermectin, selamectin, moxidectin
- isoxazolines (oral): increasingly on label
- topical: lime sulfur dips, Amitraz dips
What are the treatment conspecifics for Chyletiella spp?
Yes, treat all in contact pets (rabbits too!)
What are the treatment conspecifics for Otodectes spp?
Yes, treat all in contact Fe & Ca
What are the treatment conspecifics for Eutrombicula spp?
No, only treat if exposed to the same source
What are the treatment conspecifics for Sarcoptes spp?
Yes, treat all in contact canids
What are the treatment conspecifics for Notoedres spp?
Yes, treat all in contact Fe
What are the treatment conspecifics for Demodex spp?
No, only treat affected individuals
Is Cheyletiella zoonotic?
YES
Is Otodectes zoonotic?
YES, but rare & transient
Is Eutrombicula zoonotic?
YES, from environment
Is Sarcoptes zoonotic?
YES, but transient
Is Notoedres zoonotic?
YES, but transient
Is Demodex zoonotic?
NO
Can Cheyletiella survive in the environment?
YES, > 10 days
Can Otodectes survive in the environment?
YES, months
Can Eutrombicula survive in the environment?
YES, most of life cycle is outdoors
Can Sarcoptes survive in the environment?
YES, weeks
Can Notoedres survive in the environment?
NO
Can Demodex survive in the environment?
NO
