mites

Question 1

describe the typical mite lifecycle

Answer 1

• adult females lay only 10-15 eggs
• eggs hatch into larvae
• larvae mature into nymphs
• whole life cycle takes only 1-4 weeks

Question 2

what is acariasis

Answer 2

mite infestation

Question 3

what is severe acariasis refered to

Answer 3

mange

Question 4

what are the direct and indirect effects of mites

Answer 4

direct:
- skin erythema
- pruritus
- scale formation
- lichenification
- crust formation
- production of cutaneous hypersensitivity
- loss of blood or other fluids

indirect:
- mechanical or biological transmission of pathogens

Question 5

list burrowing mites

Answer 5

• sarcoptes
• trixacarus
• notoedres
• knemidocoptes
• demodex

Question 6

list surface mites

Answer 6

• psoroptes
• chorioptes
• otodectes
• cheyletiella
• trombicula
• dermanyssus
• orinthonyssus
• chirodiscoides
• listrophorus

Question 7

what animals are important in psoroptes infestations

Answer 7

sheep and rabbits
- sheep scab caused by psoroptes
- very irritant causing rubbing and trauma

surface mite

Question 8

what species are affected by chrorioptes bovis

Answer 8

cattle and horses
- in horses see crusting lesions above foot
- in cattle crusts in neck, tail and perianal regions
- causes loss of production due to iritation and rubbing (rarely causes trauma)

surface mite

Question 9

why species do you find otodectes cynotis in and where/what lesions look like/clinical sings/how do you diagnose

Answer 9

• ear mites of cats and dogs (and other carnivores)
• causes severe iritation and red crusts in the external ears
• if left untreated, infection can spread from outer to inner ear with possible secondary bacterial or fungal infections
• clinical signs include head shaking, continual ear scratching and ear droop, pruritus variable
• diagnose by visualising with otoscope or taking swab of characteristic black crusty wax

surface mite

Question 10

what are cheyletiella

Answer 10

• largly free living, often predatory mites
• 3 parasitic species: yasurgi (dogs), blakei (cats) and parasitivorax (rabbits)
• cause scaling dermatitis and pruritus
• usually quite mild but can be severe especially if animal already ill
• mites walking amongst debris give rise to “walking dandruff”

surface mite

Question 11

what is trombicula

Answer 11

• chiggers or harvest mites
• free living, only larvae are parasitic
• larvae are bright red/orange and 0.2mm
• ground living so often found on legs, bellies or face/head or grazers
• hypersensitivites

surface mite

Question 12

what is dermanyssus

Answer 12

• a major parasite of domestic fowls but also occurs on other birds
• dermanyssus mites live off the bird in dark places but take a blood meal at night (can and do bite humans)
• causes loss of condition, drop in egg production and in sever infestations death due to anemia

surface mite

Question 13

what is ornithonyssus

Answer 13

norther fowl mite
- blood feeder, primarily remains on the host for its entire life cycle
- can live off the host bird fo 2-3 weeks
- grey-black on feathers
- matting and scabbing especially around vent
- reduced production, anemia and occassionaly death
- may spread infections

surface mite

Question 14

what is sarcoptes scabei

Answer 14

• one species with host adapted strains, found on mammals and can jump species (zoonotic)
• highly contagious (only via direct contact)
• the entire lifecycle (17-21 days) is spent on the host
• intense pruritus probably due to hypersensitivity to mite fecal material
• diagnosed by deep skin scraping in 12 or more affected areas

burrowing mite

Question 15

what is trixacarus caviae

Answer 15

• common in guinea pigs
• burrows into the skin, may produce intense pruritus, alopecia and dermatitis
• severely infested animals may show signs of secondary bacterial infection and stress
• diagnosis is made by examining hair shafts or skin scrapings and indentifying the mite

burrowing mite

Question 16

what is notoedres cati

Answer 16

• mainly in cats, burrows into the skin and may produce pruritus, alopecia and dermatitis
• especially found on head and around ears

burrowing mite

Question 17

what is knemidocoptes

Answer 17

• causes conditions commonly known as scaly face, scaly foot or tassel foot in birds
• found in all types of domestic and wild birds
• highly contagious
• inflammation and exudate that dries
• hyperkeratosis, lameness and deformities
• pruritus, scratching…

Question 18

what is demodex

Answer 18

• highly specialised mites
• live head down in hair follicles and sebaceous glands
• usually very host specific
• normal (commensal) in low numbers
• disease most commonly seen in dogs
• often indicates underlying disease and often secondary to staphylococcal pyoderma
• can be localised or generalised
• can be chronic and difficult to treat
• one of the most important diseases of dogs youll come across

Question 19

how do you control mites

Answer 19

• treating affected animals with antiectoparasitics (fluralaner)
• treat if contagious even if asymptomatic
• treat environment for all poultry mites
• treat underlying immunocompromise