Ticks Flashcards
1
Q
What are these structures?
A
Things on either side are palps, middle thing is a hypostome
2
Q
What are the ticks established in Western Canada?
A
- Dermacentor variabilis (AB, SK, MB)
- D. andersoni (BC, AB, ~SK)
- D. albipictus (all)
- Ixodes scapularis (Southern MB)
- I. pacificus (BC)
- wildlife ticks are occasionally found on pets: Ixodes kingi, Ixodes cookei, Haemaphysalis leporispalustris (rabbit tick usually found on Fe)
3
Q
Pathogenesis of tick infestation?
A
- All ticks: anemia; dermatitis, alopecia; local bacterial infection of bites
- some ticks: paralysis: salivary toxin of female tick; alpha-gal syndrome (red meat allergy); pathogen transmission
4
Q
What are the 3 main questions to ask when ID’ing ticks?
A
- What is the shape of the capitulum?
- Is the scutum ornate?
- Are there festoons?
5
Q
How is sexual dimorphism obvious in ticks
A
- males: scutum over whole back
- females: anterior scutum
6
Q
How to ID ticks?
A
- Is the scutum coloured (ornate)? (if YES, is it white or yellow? - White splatter (Dermacentor spp); - yellow dot (Amblyoma sp. female).
- if NO, is the basis of the capitulum parallel-sided or angled? Parallel (Ixodes spp.); Angled (Rhipicephalus spp)
- Dermacentor, Amblyomma, & Rhipicephalus all have festoons
7
Q
Who is Dermacentor variabilis?
A
- American Dog tick
- 3 host tick
- potentially transmits: Rocky Mountain Spotted Fever (rickettsia), Tularemia (bacterium), Ehrlichia canis (& other spp; rickettsia)
- dominant tick in SK, MB, & east
- pathogen prevalence in ticks in western Canada is v low
8
Q
Who is Dermacentro andersoni?
A
- Rocky mountain wood tick
- transmits: Rocky Mountain Spotted Fever (rickettsia), Tularemia (bacterium), Colorado Tick Fever (virus)
- causes Tick paralysis in interior BC
- dominant tick in BC & AB
- pathogen prevalence in ticks in western Canada is v low
9
Q
What are the defining features of Dermacentor spp?
A
- ornate scutum w/ white markings, festoons, short capitulum
10
Q
what are spiracles & how can we use them to tell species apart?
A
- how the ticks breath
- small circular spots around the spiracle for Dermacentor viriabilis, large circular balls around the spiracle for Dermacentor andersoni
11
Q
What is the life cycle of Dermacentor variabilis and Dermacentor andersoni?
A
- adults lay eggs in the environment -> eggs hatch into larvae -> larvae (6 legs) go on host #2 (Rodents, rabbits, etc.) -> takes a blood meal & then drops off into the environment -> larvae become nymphs -> nymphs (8 legs) go one host #3 (rodents, rabbits, etc.) -> takes a blood meal & then drops off into the environment -> nymphs become adults -> adults (8 legs) go on to host #1 (Dogs, people, ungulates) -> take a blood meal & then drop off into
environment IN SPRING - environment = soil surface/ vegetation
- can take as little as 8 weeks, usually 2 years
12
Q
Who is Rhicephalus sanguineus?
A
- Brown dog tick
- 3 host tick (all hosts are dogs - rarely people)
- transmits: Rocky Mountain Spotted Fever (rickettsia), Ehrlichia canis (rickettsia), Babesia canis (piroplasmosis, protozoan; not in Canada), Hepatozoon canis (apicomplexan; not in Canada)
- introduced from warmer regions; seen in kennels & houses
13
Q
Defining features of Rhipicephalus sanguineus
A
- inornate scutum
- festooned
- Darth Vader helmet capitulum
14
Q
Rhipicephalus sanguineus life cycle?
A
- adults lay eggs in the environment -> eggs hatch into larvae -> larvae (6 legs) go on host (DOG, 4 days) -> takes a blood meal & then drops off into the environment -> larvae become nymphs -> nymphs (8 legs) go one host (DOG, 4 days) -> takes a blood meal & then drops off into the environment -> nymphs become adults -> adults (8 legs) go on to host (DOG, 8 days) -> take a blood meal & then drop off into environment
- environment = often indoors
- takes months to years
15
Q
Who are the Ixodids?
A
- Ixodes scapularis (I. dammini): eastern deer tick/ black legged tick
- Ixodes pacificus: western deer tick/ black legged tick
- 3 host ticks
- transmit: Anaplasma phagocytophilum, Borrelia burgdorferi (LYME DISEASE). Borrelia miyamotoi (RELAPSING FEVER), Babesia microti, Ehrlichia muris, Francisella tularensis, POWASSAN VIRUS
16
Q
Defining features of Ixodes pacificus?
A
- inornate scutum, no festoons, long parallel capitulum
- genital pore
- anal groove ANTERIOR to anus
- on dogs in BC in fall & winter
17
Q
Life cycle of Ixodes scapularis?
A
- generally takes 2-3 yrs
- adults lay eggs in the environment IN WINTER -> eggs hatch into larvae -> larvae (6 legs) go on host #2 (white foot mice, rodents, rabbits) -> takes a blood meal & then drops off into the environment -> larvae become nymphs -> nymphs (8 legs) go onto host #3 (rodents, songbirds, pets, people) IN SPRING -> takes a blood meal & then drops off into the environment -> nymphs become adults IN SUMMER -> adults (8 legs) go on to host #1 (white tailed deer, pets, people) IN FALL -> take a blood meal & then drop off into environment
18
Q
What is three-tiered tick prevention?
A
- Client education (modify behaviour & environment; tick checks & identification to genus level; remove w/in 12-24 hrs)
- tick prevention (repellents: topical insecticides, collars; systemic: oral isoxazolines, topical spot-ons)
- testing & vaccination for Lyme disease? (test only if clinical signs & plausible exposure; vaccinate only if living in or travelling to endemic regions (S. MB, ON, QC, NS, NB, eastern USA)
19
Q
What does lyme disease look like in Ca?
A
- few dogs exposed in non-endemic regions
- many dogs exposed in endemic regions
- exposure can be detected using serology (ex: 4DX snap) @ least 6-8 WEEKS AFTER TICK BITE
- 95% will never develop clinical signs
- @ 2-5 months post exposure, may see: shifting lameness (arthritis), anorexia, fever; nephritis is the most common clinical sign; rarely neurological, cardiac, & ocular issues
20
Q
A
