10a – Ticks

Question 1

Ticks established in western Canada

Answer 1

• Dermacentor variabilis: American dog tick (AB, SK, MB)
• D. andersoni: Rocky Mountain Wood tick (BC, AB)
• D. albipictus: winter or moose tick (all)
• Ixodes scapularis: eastern black legged tick (S. MB)
• I. pacificus: Western black legged tick (BC)

Question 2

Pathogenesis of ALL ticks

Answer 2

• Anemia
• Dermatitis, alopecia
• Local bacterial infection of bites

Question 3

Pathogenesis of SOME tick species

Answer 3

• Paralysis: salivary toxin of female tick (in BC)
• Alpha-gal syndrome: red met allergy
• Pathogen transmission (ex. Lyme disease)

Question 4

Hard tick ID

Answer 4

• Shape of capitulum
• Scutum ornate?
• Are there festoons?
• *sexual dimorphism obvious (male: scutum over whole back)

Question 5

Is the scutum coloured?

Answer 5

• Yes: white or yellow
• NO: basis capitulum parallel-sided or angled?

Question 6

Is scutum white or yellow?

Answer 6

• White: Dermacenter sp
• Yellow: Ambylomma sp.

Question 7

Is the basis capitulum parallel-sided or angled?

Answer 7

• Parallel: Ixodes sp.(not festooned)
• Angled: Rhipicephalus sp.

Question 8

Dermacentor variabilis: American dog tick

Answer 8

• 3 host tick
• Dominant in SK, MB and east
• Pathogen prevalence in western Canada is very low

Question 9

D. variabilis potentially transmits

Answer 9

• Rocky mountain spotted fever (rickettsia)
• Tularemia (bacterium)
• Ehrlichia canis (and other spp.; rickettsia)

Question 10

D. andersoni: rocky mountain wood tick

Answer 10

• 3 host tick
• *tick paralysis in interior BC
• Dominant tick in BC and AB
• Pathogen prevalence in western Canada is very low

Question 11

D. andersoni transmits

Answer 11

• Rocky mountain spotted fever (rickettsia)
• Tularemia (bacteria)
• Colorado tick fever (virus)

Question 12

Dermacentor adults

Answer 12

• Ornate scutum with white markings
• Festoons
• Short capitulum
• *look at spiracles for species specific ID (don’t need to know)

Question 13

Life cycle of D. variabilis and D. andersoni

Answer 13

• 8 weeks to usually 2 years (especially in Canada)
  1. Eggs in environment (soil, vegetation)
  2. Larva: 6 legged and usually onto smaller hosts and take a blood meal
  3. Drop off and become nymphs (8 legs) which go on a similar host
  4. Drop off and become adults which go on a larger host

Question 14

Rhipicephalus sanguineus: brown dog tick

Answer 14

• 3 host tick=all dogs (rarely people)
• Introduced from warmer regions, kennels, houses

Question 15

R. sanguineus transmits

Answer 15

• Rocky mountain spotted fever (rickettsia)
• Ehrlichaia canis (rickettsia)
• Babesia canis (piroplasmosis, protozoan): NOT in Canada
• Hepatozoon canis (apicomplexan): NOT in Canada

Question 16

R. sanguineus adults

Answer 16

• Inornate scutum
• Festooned
• Darth Vader helmet capitulum

Question 17

R. sanguineus life cycle

Answer 17

• Almost all hosts are dogs
• Shorter time period due to going to same host (months to years: often INSIDE)
• *similar to Dermacentors

Question 18

Ixodes scapularis and I. pacificus

Answer 18

• Eastern and western Canaada
• Deer tick/black legged ticks
• 3 host ticks

Question 19

Ixodes scapularis and I. pacificus transmits

Answer 19

• Anaplasma phagocytophilium
• Borrelia burgdorferi (Lyme disease)
• Borrelia miyamotoi (relapsing fever)
• Powassan virus

Question 20

Ixodes pacificus

Answer 20

• Inornate scutum
• No festoons
• Long parallel capitulum
• Genital pore
• Anal groove ANTERIOR to anus
• *on dogs in BC in fall and winter (but can be elsewhere due to travelling)

Question 21

Ixodes scapularis life cycle

Answer 21

• Generally takes 2-3 years
• Eggs in environment
• Larvae onto smaller host and blood meal (rodents, rabbits)
• Nymphs onto slightly bigger hosts (song birds, pets and people: SPRING)
• Adults drop and then onto white-tail deer, pets, people (FALL)
• *nymphs + larvae can NOT infect cattle as they can’t get through skin
• *cats can get

Question 22

Ixodes scapularis and cats

Answer 22

• One of the only ticks cats get
• *due to songbirds as cats hunt them

Question 23

Three-tiered tick prevention

Answer 23

• Client education
• Tick prevention
• Testing and vaccination for Lyme disease

Question 24

Client education

Answer 24

• Modify behaviour and environment
• Tick checks and ID to genus level
• Remove within 12-24hrs

Question 25

Tick prevention

Answer 25

• Repellents: topical insecticides, collars
• Systemic: oral isoxazolines, topical spot-ons

Question 26

testing and vaccination of Lyme disease

Answer 26

• Test only if clinical signs & plausible exposure
• Vaccinate only if live in or travel to endemic regions (S. MB, ON, QC, NS, NB, E. USA)

Question 27

Lyme disease and dogs

Answer 27

• Few dogs exposed in non-endemic regions
• Many dogs exposed in endemic regions
• Exposure detected using serology at least 6-8 weeks after tick bite
• 95% will NEVER develop clinical signs

Question 28

What might you see 2-5 post-exposure: Lyme disease and dogs

Answer 28

• Shifting lameness (arthritis)
• Anorexia
• Fever
• *Nephritis=most common clinical sign
• Rarely neurological, cardiac and ocular issues