10 - D/C Arthropods

Question 1

What are the lice of dogs and cats, which is chewing/sucking?

Answer 1

Dogs:
trichodectes canis - cheweing
Lingognathus setosus - sucking
Cats:
Felicola subrostratus - chewing
All louse are HIGHLY host specific - not zoonotic or only for short term

Question 2

What is the lifecycle of linognathus setosus?

Answer 2

Adult > nymph > eggs (nits) all on dog
Chewing life have same life-cycle
Entire life cycle can be completed in a few weeks

Question 3

What is the pathogenesis of pendiculosis?

Answer 3

Infestation w/ life
no effects
Dermatitis - head and back
Pruritis - itchy and hair loss
Anemia (sucking lice)
Pathogen transmission (rare)
ie. dog chewing louse IH for dipylidium caninum

Question 4

How can we dx lice?

Answer 4

young, stressed pets
older animals w/ concomitant dz
clinical appearance
direct observation - lice or nits
comb, tape +/- KOH digestion

Question 5

How do we manage lice?

Answer 5

tx w/ 1. topical insecticides as shampoo, dips, spot-ons (retx in 1-2wks, many are unsafe for cats)
2. many oral and topical flea and tick control products work on lice, often as a single application - selamectin, isoxazolines
3. Systemic tx may work better on sucking lice than chewing
Address fomites/contact with other infected animals

Question 6

How are human lice different than animal luce?

Answer 6

sucking lice ONLY
dorsoventrally flattened, wingless, six-legs, thick antennae, conical head
Pediculus spp or phthirus pubis

Question 7

What is the flea that typically affects cats?

Answer 7

ctenocephalides felis
laterally flattened
wingless
six legs
FLAT head
combs (ctenidia)

Question 8

What is the flea that typically affects dogs?

Answer 8

ctenocephalides canis
laterally flattened
wingless
six legs
ROUND head
combs (ctenidia)

Question 9

What are the life stages of a flea?

Answer 9

Egg > larva > pupa > adult

Question 10

What is the life cycle of fleas?

Answer 10

pupae live for 4-5mo: environmentally resistant resivoire
Adults feed on blood on host > eggs in enviro > larvae in enviro > pupae in enviro >
Cycle takes >3wks
ideal conditions 25-30C, 80-90 relative humidity

Question 11

What amount of fleas live as immature stages in the pets surrounding?

Answer 11

95%
5% adult fleas
10% flea pupae
35% flea larvae
50% flea eggs

Question 12

What is the pathogenesis of fleas?

Answer 12

Anemia (rare, young animals)
dermatitis
flea-bite hypersensitivity (flea-bite allergic dermatitis, FAD)
transmission:
IH for dipylidium caninum
bartonella henselae (cat scratch fever)
rickettsia spp
(yersinia pestis -plaque) rodent felas, S. SK

Question 13

WHat is flea-bite allergic dermatitis?

Answer 13

intense pruritis, but often can’t find a single flea
DDx. other allergies, mange
tx on suspicion with adulticide

Question 14

How do we dx and tx fleas?

Answer 14

dx: direct examination/ comb, flea dirt, ID testing for hypersensitivity
Tx: many products are available for flea control - most are excellent and work very quickly
Environmental (vacuum, sprays)

Question 15

What is the life cycle of cuterebra spp.

Answer 15

adult fly lays eggs around entrance to burrow in spring
L1 enters thru natural opening (nose, wound) of passing cat/dog, develops from L1-L3 in SQ of host for 3-7wks, pupa pops out from breathing hole and sits over winter before hatching as a fly

Question 16

What is the health significance, dx and tx of cuterebra?

Answer 16

generally little
rarely, abscesses in SQ, brain
Dx: swelling, breathing hole, larval emergence, seasonal timing (late summer, fall)
tx: exercise, do not crush bc anaphylaxis
zoonosis rare: dermal and nasal

Question 17

What are the sexual differences of hard ticks/ixodidae?

Answer 17

Males: scutum over whole back
Females: anterior scutum

Question 18

What are the ticks that have established in Wester Cad

Answer 18

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)

Question 19

What is the pathogenesis of tick infestation (acariasis)

Answer 19

All ticks will cause anemia, dermatitis and alopecia. They will have local bacterial infections
Some spp will cause paralysis from salivary toxin of female ticks. Alpha-gal syndrome (red meat allergies)
pathogen transmission

Question 20

How many hosts does the dermacentor variabilis tick need? What is its common name? What could it transmit and how is its prevalence?

Answer 20

American dog tick, 3 host tick
potentially transmits the rocky mountain spotted fever (rickettsia), tularemia (bacterium), ehrlichia canis (and other spp. rickettsia
prevalence in w. cad is low

Question 21

How many hosts does the dermacentor andersoni tick need? What is its common name? What could it transmit and how is its prevalence?

Answer 21

Rocky mountain wood tick, 3 host tick
trasmits rocky mountain spotted fever (rickettsia), tularemia (bacteria), colorado tick fever (virus)
*tick paralysis in BC
prevalence in w. cad is very low

Question 22

How many hosts does the ixodes scapularis tick need? What is its common name? What could it transmit

Answer 22

Eastern and western deer tick/black legged ticks, 3 host ticks
Anaplasma phagocytophilum
Borrelia burgdorferi (lyme dz)
borrelia miyamotoi (relapsing fever)
babesia microti
ehrlichia muris
francisella tularensis
powasan virus

Question 23

What are some foreign ticks to watch out for in Canada?

Answer 23

rhipicephalus sanguineus - brown dog tick, travelling from US, Europe and tropics
Amblyomma americanum - lone star tick, travelling from E. USA, alpha gal syndrome in people, cytauxzoon felis (protozoan, piroplasm) in cats
Amblyomma maculatum - gulf coat tick, travelling from SE USA, hepatozoon americanum (protozoan

Question 24

How many hosts does the rhipicephalus sanguineus tick need? What is its common name? What could it transmit and how is it introduced?

Answer 24

brown dog tick
3 host tick - all hosts are dogs (rarely people)
rocky mountain spotted fever (rickettsia), ehrlichia canis (rickettsia), babesia canis (piroplasmosis, protozoan) *not in CAD
Introduced from warmer regions: kennels, houses

Question 25

How can we dx and manage ticks?

Answer 25

dx: direct observation/clinical appearance, collect and store fresh, frozen or ethanol, identification to genus usually sufficient
Tx and control: enviro/behavioural modification, manual removal (within 12-24 hrs), repellents: topical insecticides, collars, systemic: oral isoxazolines, topical selamectin
lyme testing and vx

Question 26

What is lyme dz and its correlation with dogs?

Answer 26

a few dogs exposed in non-endemic regions
many dogs exposed in endemic regions
exposure can be detected using a 4Dx test at least 6-8 wks after tick bite
95% will never develop clinical signs
at 2-5mo post-exposure may see:
shifting lameness (arthritis), anorexia and low-grade fever, nephritis most common clinical sign, rarely neurological, cardiac and ocular tissues

Question 27

What is the life cycle of mites?

Answer 27

Adults on host w/ 8 legs > eggs* (may not be susceptible to tx), on host > larvae on host 6 legs > nymbs 1-2 on host 8 legs
cycle takes 10-21 days, does not apply to eutrombicula

Question 28

What is the pathgenesis of mite acariasis?

Answer 28

range from no effects to severe dermatitis (mange), hypersensitivity, excoriation and secondary bacterial infection

Question 29

What are the arthropods of dogs and cats?

Answer 29

mites, surface mites
cheyletiella yasguri (D)
C. blakei (cats)
C. parasitiyorax (rabbits, common)

Question 30

How long might a cheyletiella adult survive in a cool environment?

Answer 30

> 10d

Question 31

Which is more likely to have otitis due to ear mites, cats or dogs?

Answer 31

50% in cats of otitis cases
<10% in dogs
highly contagious, usually not zoonotic (transient)