Parasitology - Arthropod 3

Question 1

Body divisions of ticks and mites

Answer 1

Gnathosoma - mouth part
Idiosoma - remainder of body

Question 2

Cause & symptoms of mange

Answer 2

Skin disease caused by mites
Alopecia, erythema, pruritus — pyoderma

Question 3

Similarities of mites & lice

Answer 3

Host specific
All life stages on host/parasitic
Short life cycle (few weeks)
Transmission - direct contact

Question 4

Differences of diagnosis of lice & mites

Answer 4

Mites - skin scraping
Lice - visual/microscope

Question 5

Subsurface mites

Answer 5

Sarcoptes
Knemidocoptes
Demodex

Question 6

Surface mites

Answer 6

Otodectes
Chorioptes
Psoroptes

Question 7

Morphology of sarcoptic mites

Answer 7

Round bodies
Posterior legs visible ventrally
Burrowing mites in epidermis

Question 8

Most common cause of mange

Answer 8

Sarcoptic mites

Question 9

What species do sarcoptes scabiei infect?

Answer 9

Dogs, pigs, cattle*, horses**
Very host specific
Reportable in cattle

Question 10

Pathogenicity of sarcoptes scabiei

Answer 10

Lesions on face, ears, legs
Pruritus, alopecia, inflammation

Question 11

Chronic sarcoptic mange

Answer 11

Sarcoptes scabiei
Alopecia, thickened wrinkled skin
Pyoderma - secondary bacterial infection is common
Self inflicted trauma from scratching

Question 12

Range of difficulty when diagnosing sarcoptes scabiei

Answer 12

Acute mange - easier, lesions more clear
Chronic mange - more difficult, no clear lesions, bacterial infection contamination

Question 13

Treatment and control of sarcoptes scabiei

Answer 13

Drugs are effective, no known resistance
Zoonotic - humans can contract lesions but wont reach a full life cycle

Question 14

Sarcoptic mites alternate hosts

Answer 14

Cats, rabbits, Guinea pigs

Question 15

Demodex spp morphology

Answer 15

Cigar with legs, burrow deeper in skin
Larvae have 3 pairs of legs
Adults have 4 pairs of legs

Question 16

What animal species have multiple mite Demodex species?

Answer 16

Cats and dogs

Question 17

Location of Demodex mites

Answer 17

Hair follicles or sebaceous glands
Part of the normal skin flora (selective immunity)

Question 18

Clinical signs of Demodex mites

Answer 18

Disease is common is dogs
Infection varies based on problem in immune system
Localized or generalized

Question 19

Features of surface mites

Answer 19

Otodectes, chorioptes
Not borrower, superficial
More oval, longer legs, posterior legs are visible dorsally
Life cycle min 2 weeks

Question 20

Location & pathogenesis of Otodectes cynotis

Answer 20

Ear canal of dogs, cats, ferrets
Most common in cats, easily transmitted
Cause otitis externa — pruritus

Question 21

What mite causes coffee ground appearance?

Answer 21

Otodectes cynotis
Surface mite

Question 22

Chorioptes spp

Answer 22

Most common large animal mite
Specifically in cattle

Question 23

Pathogenesis & location of chorioptes

Answer 23

Cattle: tail head, back of udder/perineal region
Small ruminants: scrotum, can cause infertility
Horses: lower leg/body

Question 24

Order Acarina - ticks
Importance

Answer 24

Bite wounds
Blood loss
Tick paralysis
Transmission of pathogens**

Question 25

Tick-borne diseases

Answer 25

Lyme borreliosis Anaplasmosis Babesiosis Ehrlichoiosis RMSF Cytauxzoonosis

Question 26

Two families of ticks

Answer 26

Hard ticks - important Soft ticks

Question 27

Nomenclature for hard ticks

Answer 27

Ixodidae

Question 28

Nomenclature for soft ticks

Answer 28

Argasidae

Question 29

Appearance of ixodids

Answer 29

Shiny, scutum distinguishes M/F Mouth parts project forward

Question 30

Life stages & important of molting in ticks

Answer 30

Egg, larva, nymph, adults Cuticle restricts growth - molt occurs in environment All common ticks are 3-host ticks

Question 31

Morphology of nymphs

Answer 31

M/F have 8 legs Lack genital opening

Question 32

Morphology of adult ticks

Answer 32

M/F have 8 legs Genital opening Mate on host Females lay eggs in environment & die

Question 33

Attachment tools for ticks

Answer 33

Hypostome - needle Palp - gribbers

Question 34

Tick feeding

Answer 34

Slow feeding, several days Rapid feeding, 12-36 hours prior to detachment

Question 35

Blocking functions of tick saliva

Answer 35

Histamine blocker Anticoagulant Paralytic toxins cause ascending motor paralysis

Question 36

Enlarging features of tick salvia

Answer 36

Cytolysins enlarge feeding lesion Vasoactive mediators that increase vascular permeability

Question 37

Facilitated transmission (horizontal)

Answer 37

Trans-stadial transmission Picks up disease as larva or nymph, transmits to subsequent host

Question 38

Facilitated transmission (vertical)

Answer 38

Transovarial transmission Disease agent in female tick passes into eggs and is passed through subsequent stages

Question 39

How many common hard ticks species?

Answer 39

Big 4 species

Question 40

Common name of dermacentor variabilis

Answer 40

American dog tick

Question 41

Common name of Ixodes scapularis

Answer 41

black legged/deer tick

Question 42

Common name for Amblyomma Americanum

Answer 42

Lone star tick

Question 43

Common name for Rhipicephalus sanguineus

Answer 43

Brown dog tick

Question 44

Common name of invasive tick in US

Answer 44

Asian longhorn tick

Question 45

Scientific name for Asian longhorned tick

Answer 45

Haemaphysalis longicornis

Question 46

Argasid ticks

Answer 46

Soft ticks More successful in environment Several nymph stages Don’t transmit major diseases in the US