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VETM 424 Parasitology > Lecture 11: Ticks > Flashcards

Lecture 11: Ticks Flashcards

1
Q

What is the taxonomy of ticks (Phylum to Family)

A
  • Phylum: Arthropoda
  • Subphylum: Chelicerata (no antenna)
  • Class: Arachnida
  • Subclass: Acari- mite/tick
  • Superorder: Parasitiformes
  • Order: ixodida
  • Families:
    o Argasidae: soft ticks
    o Ixodidae: hard ticks
    o Nuttaliellidae
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2
Q

What are the morphological features of Argasidae ticks

A

 Mouthparts not visible when looking down on them
 Rough cuticle
 No scutum
 No sexual dimorphism

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3
Q

What are the morphological features of Ixodidae ticks

A

 Can see mouthparts
 Smooth cuticle
 Sexual dimorphism via scutum

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4
Q

Compare the feeding habits and life stages of Argasidae and Ixodidae ticks

A

Argasidae:
 Feeding: multiple bloodmeals per life stage (short feeding time)
 Multiple nymphal stages
 Nocturnal
 Drry/seemi arid habitat

Ixodidae
 Feeding: 1 bloodmeal per life stage (longer feeding)
 1 nymphal stage

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5
Q

What are the general morphological structures of ticks

A
  • Chitin exoskeleton
  • Segmented body
  • Pared segmented appendages – 4 walking legs
    o Attach at ‘coxa’ (hard plates – can be used for ID)
  • Spiracles behind last leg used for breathing
  • 2 body regions
    o Gnathosoma
    o Idiosoma
  • Toothed hypostome
  • Sensory complex on front legs (tarsus 1)
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6
Q

What are the 3 parts of the Capitulum in an Ixodidae tick

A
  • Capitulum (contain feeding parts)
    o Palps: 4, paired and segmented
    o Chelicerae: cutting, paired
    o Hypostome: recurved teeth (saw-like)
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7
Q

What makes up the Gnathosoma of a ticks

A
  • Gnathosoma (head)
    o Capitulum
    o Basis capitula – important for ID
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8
Q

What are the 2 main sensory organs of a tick? How do they differ between species

A
  • Haller’s organ: sensory for host detection – on front legs (tarsus 1)
  • Eyes: photoreceptors on periphery of idiosoma
    o Not in Ixodes and Haemophysalis spp
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9
Q

What is the anal groove and how is that used for identification of ticks

A
  • Anal groove: on ventral tick – can distinguish between different genera
    o Ixodes: anal groove is cranial to anus = prostriata
    o Other ticks: caudal to anus = metastriata
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10
Q

How is ornamentation used for identifying ticks

A
  • Ornamentation: on scutum – colour
    o Inornate (dark/monochrome scutum) vs ornate (light colour/patterns)
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11
Q

What are festoons and how are they used for identification

A
  • Festoons: small lines at caudal edge of tick
    o Not in Ixodes and Rhipicephalus
    o If engorged = difficult to see
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12
Q

What type of animal are ticks

A

Lifecycle: obligate parasite

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13
Q

What is the general life cycle/stages of a Argasidae tick

A
  • 50-200 eggs laid per female
  • Larvae: 6 legs, no spiracular plates, +/- scutum
  • Nymph (2-8 instar): 8 legs, spiracular plate, no genital pore
  • Adult: genital pore acquired
  • Life cycle can take 2 years or even up to 10 years
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14
Q

What is the general lifecycle/stages of an Ixodidae tick

A
  • Egg: thousands
  • Larvae: 6 legs, scutum present
  • Nymph (1 instar): 8 legs (size of poppy seed)
  • Adult: 8 legs, scutum (male and female differ), genital pore
  • 1 or 3 host ticks
    o 1 host tick: feed on same animal for each life stage
    o 3 host tick: feed don different animals for each life stage (most)
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15
Q

What are the steps of feeding (Ixodidae tick)

A

Ixodidae
* Questing (host seeking): via chemical/heat/light cues

  • Locate site on host
  • Attach
  • Feeding: slow feeding then mate
    o After mating females will rapidly feed and engorge
    o Males will take less blood than females because they have a bigger scutum
  • Use mouthparts: chelicera and hypostome
  • Cuticle accommodates growth
  • Water regulation: excess intake result in salivary gland growth and secretions
    o Saliva: acts like cement around mouth parts, anticoagulant, immunomodulator
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16
Q

Where are the salivary glands of an Ixodidae tick located

A

o Salivary glands are in the main body of tick (will not retain if remove tick)

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17
Q

What are 10 common species of Ixodidae ticks

A

Dermacentor variables (american dog tick)

Dermacentor andersoni (rocky mountain tick)

Dermacentor Albipictus (winter/moose tick)

Ixodes scapularis (deer tick

Ixodes pacificus (western black legged tick)

Rhipicephalus sanguineus

Haemaphysalis leporispalustris (rabbit tick)

Haemaphysalis chordeilis (bird/grouse tick)

Haemaphysalis longicornis (asian longhorned tick)

Orrnithodoros spp (ascarid)

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18
Q

What are Dermacentor ticks common vectors for?

A

Anaplasmosis

Rocky Mountain Spotted Fever

Tularemia

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19
Q

How are dermacentor ticks morphologically different

A

each has different shaped spiracular plates with different shaped goblets (bumps)

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20
Q

Bovine anaplasmosis
- vector?
- agent?

A

o Bovine anaplasmosis: carried by Dermacentor spp
 Agent: Anaplasma marginale (rickettsia)

21
Q

Bovine anaplasmosis
- pathogenesis?
- clinical signs?

A

 Infect RBC (see them at the periphery of the RBC)
 Clinically: fever/dyspnea/hemolytic anemia/icterus
 50% mortality with virulent strain (more severe if older host)
* Recovered animals may be persistently infected

22
Q

How is bovine anaplasmosis transmitted

A

 Transmit: ingested by ticks or other arthropods
* Ticks: biologic (amplify bacteria in tick) or mechanical (biting flies) transmission
* Vertical transmission
* Fomite; contaminated with blood

23
Q

What species of tick is the american dog tick

A

Dermacentor variabilis

24
Q

What is the lifecycle of Dermacentor variabilis and where is it located

A

 2 year life cycle: 3 host tick
* Mice/deer/bird

 Seasonality
* Adult and larvae overwinter
* Adult: late march/mid august (may/june is peak)
* Egg: June
* Larvae: June -Sept
* Nymph: may – Aug

 Located: central – E NA (more humid enviro)

25
Q

What is the lifecycle and location of Dermacentor andersoni

A

 2 year life cycle: 3 host
 Hosts
* Larvae: rodent
* Nymph: rodent/rabbit (nymph stage overwinter)
* Adult: people/dog/cow/wildlife
 Location: montane region/grasslands/prairie

26
Q

What is the species name for the rocky mountain wood tick

A

Dermacentor andersoni

27
Q

What is a common disease transmitted by Dermacentor andersoni? Who does it affect and how?

A

 Tick paralysis: BC, march – may
* Female ticks inject neurotoxin causing ascending flaccid paralysis
* Will kill host (paralysis of diaphragm)
* Can affect people/cow/sheep/pig/horse/dog/deer/marmot

27
Q

What is the species name for the moose tick?

A

aka winter tick

Dermacentor albipictus

28
Q

What is the lifecycle and location of Dermacentor albipictus

A

o albipictus (winter/moose tick): N Mexico/US/CA
 1 year life cycle: 1 host
 Target: caribou/cattle/horses/moose

29
Q

What is a common disease/clinical sign of Dermacentor albipictus

A

 Often pick up hundreds (all holding on to each other)
 Clinically: ghost moose (massive infestation = hair loss/reduced grazing/blood loss/poor BCS) common in late winter/early spring

30
Q

What are common diseases transmitted by Ixodes ticks

A

Borelliosis (Borellia burgdorferi)

Anaplasmosis

31
Q

What is the lifecycle of Ixodes ticks

A

o 3 year – 3 host ticks
o Wide host range

32
Q

What is the species name for the deer tick

A

Ixodes scapularis

33
Q

Where is Ixodes scapularis located and what are distinguishing morphological features

A

 Location: E NA
 Basis Capitulum: small bumps (cornua)
 Scutum: circular, widest in middle

34
Q

What is the species name of the western black legged tick

A

Ixodes pacificus

35
Q

Where is Ixodes pacificus located and what are the distinguishing morphological features

A

 Location; W NA
 Basis Capitulum: no bumps
 Scutum: oval/widest in middle

36
Q

Lyme borreliosis
- agent?
- target?
- clinical signs?

A

o Lyme borreliosis: Borrelia burgdorferi
 Target: cat/dog/horse/cattle/people
 Dog: mild
 Cat: unknown signs
 Horse: arthritis

37
Q

What diseases is Rhipicephalus sanguineus a common vector for

A

Babesiosis
Piroplasmosis
Rocky Mountain Spotted Fever

o Vector: Erlichia canis/Babesia canis/Rickettsia rickettsii

38
Q

What is the lifecycle of Rhipicephalus sanguineus

A

o 3 host tick
o High infestation levels
o Can reproduce indoors (problem in kennels)

39
Q

What common disease is spread by Haemaphysalis spp ticks? Where are these ticks located

A
  • Haemaphysalis: Theilieriosis

in NA

40
Q

What is Haemaphysalis longicornis a vector for?

A

 Vector: Rickettsia rickettsii, heartland virus, Theileria orientalis (infect bovine), Powassan virus

41
Q

What is a feature of Haemaphysalis longicornis that makes it a big problem

A

o Longicornis (Asian longhorned tick): in Asia but has rapidly spread in NA
 Heavy infestations = direct injury (livestock)
 Asexual repro (female can reproduce independently)

42
Q

What disease does the Ornithodoros spp of tick transmit

A

o African swine fever

43
Q

What are the relevant species of Argasidae ticks

A

 Argas persicus (fowl tick)
 Ornithodoros hermsi
 Otobuis megnini (spinose ear tick)
 Argas cooleyi
 Carios concanensis
 Carios kelleyi
 Ornithodoros parkeri

44
Q

What is the importance of Argas pericus

A

o Nidicolous
o Blood loss
o Vector: poultry pathogen

45
Q

What is the importance of Ornithodoros hermsi

A

 Ornithodoros hermsi: BC
o In rodent nest/attics
o Vector: Borrelia hermsi (reccurent fever)/ASF

46
Q

What is the importance of Otobuis megnini

A

 Otobuis megnini (spinose ear tick): BC
o Target; cattle/deer/horse
o 1 host lifecycle: adult doesn’t feed (only larvae/nymph)

47
Q

How to control ticks in livestock populations

A

Livestock: integrated pest management (multiple methods to prevent and manage)
 ID tick: will inform management
 Prevention is better
 Confirm pesticide is currently approved for use

48
Q

How to control ticks in small animals

A

SA: prevent (avoid tick areas/repellant/acaricides)
 Tick checks
 Remove

VETM 424 Parasitology (12 decks)

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