Mites

Question 1

Describe the anatomy of adult acari (ticks and mites)

Answer 1

8 legs
non-segmented body

Question 2

What is acariasis?

Answer 2

Mite infestation

Question 3

What is mange?

Answer 3

severe acariasis/mite infestation

Question 4

Describe the direct effects of mites

Answer 4

Direct epidermal damage:
- skin erythema, pruritus, scale formation, lichenification and crust formation
- production of cutaneous hypersensitivity
- loss of blood or other fluids

Question 5

Describe the indirect effects of mites

Answer 5

Mechanical or biological transmission or pathogens

Question 6

What is the effect of psoroptes mites

Answer 6

Surface mite
Often very irritant, causing rubbing and trauma
Sheep scab
Rabbit ear mites

Question 7

Describe the effect of chorioptes mites

Answer 7

Surface mite
Most common cause of mange in cattle and horses
Irritant, causes rubbing
Localised infestations and lesions
Loss of production

Question 8

Describe the effect of otodectes cynotis mite

Answer 8

Surface mite
Ear mites in cats and dogs => severe irritations and thick, red crusts
Head shaking, ear scratching, ear droop, pruritus

Question 9

Describe the effect of cheyletiella mites

Answer 9

Surface mites
Cause scaling dermatitis and pruritus

Question 10

Describe the effect of trombicula mites

Answer 10

Surface mites
Bright red larvae
Found on legs, belly, face/head of grazers
Hypersensitivity reaction to bites => pruritis, erythema, scratching

Question 11

Describe the effect of chirodiscoides and listrophorus mites

Answer 11

Surface mites
Fur mites
Few clinical signs

Question 12

Describe the effect of dermanyssus mites (chicken red mites)

Answer 12

Surface mite
Affects fowls
causes loss of condition, drop in egg production and death due to anaemia

Question 13

Describe the effect of ornithonyssus (northern fowl mite)

Answer 13

surface mite
Blood feeder
matting and scabbing around vent
reduced production, anaemia, death

Question 14

Describe the effect of sarcoptes scabei mites

Answer 14

Burrowing mite
highly contagious
Intense pruritus due to hypersensitivity

Question 15

Describe the effects of trixacarus caviae mites

Answer 15

Burrowing mites
Intense pruritus, alopecia and dermatitis
Severe infection -> secondary bacterial infection and stress

Question 16

Describe the effects of notoedrea cati mites

Answer 16

Burrowing mites
pruritus, alopecia and dermatitis
found on head and around ears of cats

Question 17

Describe the effect of knemidocoptes mites

Answer 17

Burrowing mites
Scaly face, scaly foot, tassel foot in birds
Highly contagious
Inflammation and exudate that dries
Hyperkeratosis, lameness, deformities
pruritis, scratching

Question 18

Describe the effect of demodex mites

Answer 18

Burrowing mites
Live head down in hair follicles and sebaceous glands
Normal in low numbers
Most commonly causes disease in dogs:
- Hair loss
- scabby, crusty, itchy skin

Question 19

Describe the methods of mite control

Answer 19

Treat infected animals
Treat in-contact animals if contagious
Physically clean environment
Identify and treat possibly underlying immunocompromse (important in demodex)

Question 20

How do you differentiate between burrowing and surface mites?

Answer 20

Surface mites have longer legs
Burrowing mites have short stubby legs