Dogs and cats arthropods Flashcards
Lice of dogs
Trichodectes canis- shewing
Lignoghathus setosus- sucking
Lice of cats
Felicola subrostratus-chewing
Life cycle of sucking louse
Entire life cycle on host
Eggs(nits)
Nymph
Adult- suck blood
Pathogenesis of pediculosis
No effects
Dermatitis- head and back
Pruritus (itchy) and hair loss
Anemia (sucking lice)
Pathogen transmission (rare)
I.e. dog chewing louse IH for Dipylidium caninum
Diagnosis of lice
Young, stressed pets
Older animals with concomitant dz
Clinical appearance
Direct observation
Lice or nits
Comb, tape +/- KOH digestion
What to treat for lice
Topical insecticides as shampoo, dips, spotons
Have to retreat in 1-2 weeks (nits resistant)
Many of these are unsafe for cats
Many oral and topical flea and tick control products work on lice, often as a single application
Selamectin, isoxazolines
Systemic treatments may work better on sucking lice then chewing lice
Address fomite/contact with other infected animals
Human lice
Sucking lice ONLY
Head, body, and pudic lice
Rarely may find on pets (not source!)
Dorsoventrally flattened, wingless, six legs, thick antennae, conical head
Have eyes animal lice do not
Fleas in cats and dogs
Ctenocephalides felis (CATS, DOGS >50 spp)
Ctenocephalides canis (dogs, wild canids)
Pulex spp. (and many other species)(birds, wildlife,s sometimes pets)
95% of fleas live as immature stages in the pets surroundings
Cat flea looks like
Flat head
Laterlly flattened
Wingless
Six legs
Combs (ctendia)
Dog flea looks like
Round head
Pronotal combs
Genal combs
Life cycle of flea
Pupae live for 4-5 months: environmentally resistant resevoir
Life cycle last at least 3 weeks
Adults on host
eggs in enviro
larvae in enviro
pupae in enviro
Pathogenesis of fleas
Anemia (rare, young animals)
Dermatitis
Flea-bite hypersensitivity (flea-bite allergic dermatitis, FAD)
Pathogen transmission
IH for dipylidium caninum
Bartonella henselae (cat scratch fever)
Rickettsia spp. (Yersinia pestis-plague)- rodent fleas
Flea-bite allergic dermatitis
Intense pruritus, but often can’t find a single flea
Ddx: other allergies, mange
Treat on suspicion with adulticide
Diagnosis of fleas
Direct examination/comb
Flea dirt
Intradermal testing for hyposensitivity
treatment for fleas
Many products are available for flea control
Most are excellent and work very quickly
Environmental (vacuum, sprays)
Life cycle of Cuterebra spp
Adult fly lays eggs around enterance to burrow in spring
Larvae (L1) enters through a natural opening (nose or wound) of passing dog or cat
Develops from l1-3 in SQ of host for 3-7 weeks
Pupae overwinters in environment
Grows to Adult
Health significance, diagnosis and treatment of Cuterebra
Generally little
Rarely, abscesses in SQ, brain
Diagnosis: swelling, breathing hole, larval emergence, seasonal timing (late summer, fall)
Rx: excise, do not crush-anaphylaxis!
Zoonosis rare: dermal and nasal
Family Ixodidae (hard ticks) sex’s are determined by
Sexual dimorphism obvious
Males: scutum over whole back
Females: anterior scutum
Scutum may be ornate
Festoons may be present
Ticks established in western canada
Dermacentor variabilis, american dog tick (AB, SK,MB)
D.andersoni, rocky mountain wood tick (BC, AB,SK)
Ixodes scapularis, eastern black legged tick (only southern MB-so far)
I.pacificus, western black legged tick (BC coast)
Wildlife ticks are occasionally found on pets
Pathogenesis of tick infestation (acariasis)
All ticks
Anemia
Dermatitis
Alopecia
Local bacterial infection of bites
Some sp.
Paralysis: salivary toxin of female tick
Alpha-gal syndrome (red meat allergy)
Pathogen transmission
Dermacentor variabilis is and can transmit
American dog tick
3 host tick
Potentially transmit
Rocky mountain spotted fever (rickettsia)
Tularemia (bacterium)
Ehrlichia canis (and other spp,; rickettsia)
Pathogen prevalence in western canada very low
Dermacentor andersoni is and transmits
Rocky mountain wood tick
3 host tick
Transmits
Rocky mountain spotted fever (rickettsia)
Tularemia (bacteria)
Colorado tick fever (virus)
Tick paralysis in BC
Pathogen prevalence in western canada very low
Types of ixodid ticks
ixodes scapularis (I.dammini)
I. pacificus
Eastern and western (respectively)
Deer tick/black legged ticks
3 host ticks
Anaplasma phagocytophilum
Borrelia burgdorferi (lyme disease)
Borrelia miyamotoi (relapsing fever)
Babesia microti
Ehrlichia muris
Francisella tularensis
Powassan virus
Foreign ticks to watch for in canada
Rhipicephalus sanguineus, brown dog tick
Travel from US, europe, tropics
Amblyomma americanum, lone star tick
Travel from eastern USA (S.ON?)
Alpha gal syndrome in people
Cytauxzoon felis (protozoan, piroplasm) in cats
Amblyomma maculatum, gulf coast tick
Travel from south eastern USA
Hepatozoon americanum (protozoan, apicomplexan) in dogs
Rhipicephalus sanguineus is and can transmit
Brown dog tick
3 host tick- all hosts are dogs (rarely people)
Rock mountain spotted fever (rickettsia)
Ehrlichia canis (rickettsia)
Babesia canis (piroplasmosis, protozoan) *not in Canada
Introduced from warmer regions; kennels; houses
Diagnosis of ticks
Direct observation/clinical appearance
Collect and store fresh, frozen or ethanol
Identification to genus usually sufficient
Treatment of ticks
environmental/behavioural modification
Manual removal (within 12-24 hours)
Repellents: topical insecticides, collars
Systemic: oral isoxazolines, topical selamectin
Lyme testing and vaccination?
Lyme disease and dogs
A few dogs exposed in non endemic regions
Many dogs exposed in endemic regions
Exposure can be detected using 4dx test at least 6-8 weeks after tick bite
95% will never develop clinical signs
What might you see with dogs with lyme and when
At 2-5 months post exposure, may see
Shifting lameness (arthritis), anorexia and low-grade fever
Nephritis most common clinical sign
Rarely neurological, cardiac, and ocular issues
Life cycle of mites
Adults lay eggs
Larvae hatch-have six leggs
Nymphs - devlope to 8 legs
life cycel takes at least 10-21 days
Pathogenesis of mite acariasis
Range from no effects to severe dermatitis (mange)
Hypersensitivity
Excoriation and secondary bacterial infection
Surface mites of dogs and cats
Cheyletiella yasguri (dogs)
C.blakei (cats)
C. parasitivorax (rabbits, common)
Zoonotic
Eat mites are and cause
Otodectes cynotis (CATS, dogs)
50% of otitis cases in cats is due to ear mites
<10% of otitis cases in dogs due to ear mites
Highly contagious, usually not zoonotic (transient)
Otodectes mites clinical signs
Pruritus
Head shaking
Behavioural disturbances (hypersensitivity)
Worse in young and immunocompromised
Burrowing mites in cats and dogs
Sarcoptes sp.- canine scabies mite
Notoedres sp. - feline scabies mite
Demodex spp.- demodectic mange
Characteristics of sarcoptes
Highly contagious with other dogs, wild canids, transiently zoonotic (self resolving)
Adults survive in cool, humid environments for up to 3 wks
Characteristics of Notoedres sp
Smaller than Sarcoptes
Highly contagious among cats; transient zoonoses
Signs of sarcoptic mange
Hairless ares
Ears, elbows, ventrum, tarsal
Intense pruritus (HS)
Erythema
Crusts
Hair loss, excoriation
Hyperkeratosis
+/- mites
Signs of Notoedres sp.- feline scabies
Ears
Then face, slides +/- feet and perineum
Intense pruritus
Dey, crusty skin
Hair loss, excoriation
Hyperkeratosis
Lymphadenopathy
Demodex spp are and how are they transmitted
Dog: D.canis
Cat: D.cati, demodex sp.
Not zoonotic, not contagious
No environmental survival
“Vertical” transmission; close contact with dam
Live in hair follicles and sebaceous glands (squeeze!)
Eight legs on thorax
Demodectic mange in dogs
Clinical presentations
Most asymptomatic (normal fauna)
Localized demodicosis
Generalized demodicosis
Localized demodicosis is common in and signs
Young (3-18 months)
Mouth
Eye
Forelegs
Rarely ear canal
Focal alopecia
Silver scaling
Not pruritic
Self resolving: most cure within 1-2 mos
Generalized demodicosis is and c/s
Any age,better prognosis for young
Starts face and limbs
> or equal to 5 lesions
Pustular form
Folliculitis
Hyperkeratosis
Painful, not pruritic unless 2* bacteria
Even sepsis, death
Demidicosis in young animals
(3-18 months)
Localized: excellent prognosis, often self recovery
Generalized (family history, purebreds, severe stress): good prognosis with treatment
Older animals with demodicosis
(>1.5 years), generalise form
Often underlying immune deficiency, concurrent disease, reproductive stress (heat cycles)
Poor prognosis, difficult to treat (60-80% cure rate)
How to treat demodicosis
Isoxazolines, moxidectin/imidacloprid, amitraz
Antibiotics, nutritional support, grooming
Do not use parent or pups for breeding
Feline demodicosis
Rare
D.cati: eyelids, head, neck
Localized often resolves spontaneously
Generalized: check for underlying disease (FLV, FIV)
D.gatoi: pruritic, contagious
Often no underlying disease
Diagnosis of mites
History and clinical appearance
Burrowing
-Multiple, deep skin scrapings +/- KOH digest
-Biopsy?
Surface
-Tape, comb, vacuum, hand lens, fecal (cats!)
Ear/nose
-Otoscopy, rhinoscopy and swab (mineral oil)
How to treat mites
Macrocyclic lactones (oral, topical, parateneral)
Ivermectin, selamectin, moxidectin
Isoxazolines (oral)
Topical: lime sulfer dips, amitraz dips
