Mites As Parasites Flashcards

1
Q

Mite pathway to inflammation

A

Mechanical abrasion and allergen deposition cause skin barrier disruption
Activates 1o rec cause release of inflam med IL6&8 and TNF trigger pro inflam cascade cause selectin and integrin expr
Cause leukocyte extravasation activating local DCs bridging innate to adaptive resp and causing loxal skin inflam
DC cell act TH2 resp which causes further disruption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Host resp to mange mites

A

Prod immediate inflam resp
Adaptive imm resp bia APCs
Innate imm eg eosins in stratum corneum
Protective imm takes time to dev

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Adaptation to surf living

A

Large mites
Stout bodies
Long legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Adaptation to living in epidermis

A

Small mites
Flattened round bodies
Short legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Adaptation to living within follicle

A

Small Elongated body

Very stubby legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Adaptation to free living

A

Large

Very long legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Diagnosis of infestations in diff areas

A

Surf: tape strip or superficial skin scrape
Burrowing: deep skin scrap
Hair follicle: squeeze pustules onto slide
Specific sites: direct observation
Other diagnostic tests: haematology, chemistry, serology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mange diagnosis

A

Clinical signs
Lesion distribution
Mite ID on skin scrapes or adhesive tape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mange mite lifecycle

A

Eggs laid on skin (or other niche) and larvae dev in approx 3d
Larvae feed for 3-7d then moult
Nymphs emerge and change into males and pubescent females after 5d
About 3-4wk to complete
All dev stages on host and transmission by close contact (or rarely short survival period on fomites)
Susceptible to dessication so dont survive long off host
rarely able to infect new host of survived off host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Psoroptes ovis lifecycle

A

Same as gen mange mite lifecycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Psoroptes ovis

A

Sheep scab
Cause of intense pruritus and after 6 wk wool loss and skin damage timescale dep on strain of mite, time of hr, length of wool, etc
Important animal welfare concern
Important cause of production loss
ND in scotland
Large money spent on inneffective disease control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sheep scab as an ND

A

Legal obligation to notify DVM in scotland
Voluntary movement restrictions until treated slaughtered or negatively diagnosed
Failure to act can lead to compulsory movement restrictions and req to treat or slaughter affected animal in absence of negative diagnosis
Persistent offence can lead to prosecution
Powers to act when sheep scab discovered at market and deal with stray sheep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sheep scab symptom progression

A

6wk post: clear serous exudate, crust formation which adheres to wool fibres and start to lift off skin
10wk post: wool loss area, skin with no wool is dry and hardened and hyperkeratatic, margin area exudative
3mnth post: epiderm split into layers and mite pop between each layer
Exudate is pro rich and so become quickly hyperprotonaemic so lose weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Psoroptes cuniculi

Rabbit ear canker

A

Diff to distinguish from ovis
Localise ears and prolif to severe mange
Scales cont parasite, mite eggs, skin cells and blood can block auditory canal
Untreated can spread to whole body causing pruritus hair loss and debilitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Chorioptes

A

Surf mites with bell shaped suckers on short pedical
Hypersens reaction causing exudative dermatitis
Variable pruritis level along with scaling hair loss and crusting
Host specific variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Goat chorioptic mange

A

Dry crusting scabs on lower limbs
Severe exudative dermatitis affecting whole body of individuals with matted overlying hair
Severe pruritis

17
Q

Sheep chorioptic mange

A

Exudative dermatitis of wool less areas of lower limbs and poll (and scrotum of rams which reduces ram breeding soundness if over a third of the scrotum is affected)
Scab covered erythematous lesions which progress to exudative haemmorrhagic fissured lesions
Re emergence coincide with removal of compulsory dipping fo sheep scab? As it is not controlled by systemic endecticides

18
Q

Cattle and horse chorioptic mange

A

Lesions tend to be localised
Tail head of cattle
Pasterns of horses (greasy heel)

19
Q

Otodectes cynotis - ear mites

A

Bell shaped suckers on short pedicel
Dogs and cats
Most animals infested with commensals
Hypersens to allergens produced during feeding
Signs range from asympt to severe
Young animals acquire from dam during suckling

20
Q

Sarcoptes scabiei - sarcoptic mange

A

Burrowing mite
Esp in foxes dogs and pigs (host spec variants)
Highly contag and easy to spread
Temporarily zoonotic
Hypersens causes intense pruritus and severe inflam and scaling crusting and hair loss
Cause scabies in humans

21
Q

Sarcoptic mange in pigs

A

Burrow within epidermis
Now rare due to control measures
Introduced with bought animals and spread by close contact
Cause papular eruptions, erythema, pruritus and hair loss leading to skin thickening and crusting
Loss of appetite and weight loss
Lesions start around the edges of ears and spread over the body

22
Q

Sarcoptic mange in dogs and foxes

A

Intense pruritus
Lesions begin on ears and spread over the body
Similar to dis in other species

23
Q

Sarcoptes scabiei var ovis

A

Problem in S EU - present in UK???
Burrowin mites
Intense pruritus and thick crust formation
Affects face, groin, limbs and axillae esp

24
Q

Psorobia ovis

A

Non burrowing
Deep in superficial epid of sides, flanks and thighs of fine wooled breeds
Not in UK
Mild prurirtus, tuft of wool displacement, self excoriation
Gives dry scaly and hyperkertotic skin (fleece bound together by scurf)
Devalues fine wool in Aus

25
Q

Notedres cati - notedric mange in cats

A
Rare in Uk
Key in EU
Contagious
Zoonotic 
Intensely pruritic
26
Q

Trixacarus caviae (guinea pig mite)

A

Burrowing (similar to sarcoptes)
Transmission fron mother to offspring
Inflam severe pruritis scaling self trauma and sometimes death

27
Q

Knemidocoptes pilae - depluming itch mites and scaly leg mites of birds

A

Scaly feet and wings

28
Q

Demodex - demodectic mange

A

Commensals on most mammals (hist spec variants)
Transferred from dam to offspring during suckling but otherwise not contagious (except d. Gatoi)
Not usually pruritic (except d gatoi)
Affects face limbs eyelids and back
Can cause severe dis in immunocompromised animals

29
Q

Cattle and sheep demodectic mange

A

Usually clin insignificant occassionally obvious
Aesthetic and hide dam in production from follicular infection
Dam to face of calf transmission in suckling
Non pruritic
Can cause hypertrophy of the sebaceous glands

30
Q

Cheyletiella

VECTOR!!!

A
Common in dogs and rabbits
Highly contag in rabbit colonies
Walking dandruff
Variable pruritus
Myxomatosis transmission
Zoonotic: can penetrate clothing after only short contact period with an infected animal, can cause persistent irritation and pruritus, early erythrmatous lesions can progress to vesicular and pustular eruption and dev persistent rash, resolve spontaneously once treated in the natural host
31
Q

Mycoptes and myobia - rodent fur mites

A

Live on and amongst hair not on the skin

Low grade pruritus and alopecia in severe infestations

32
Q

Thrombiculids- harvest mites

A
Parasitic as larval stage 
Nymph and adult live on decaying vegetation
Common in dogs and cats
Seasonal summer occurance
High prevalence in SE Scotland
Severe irritation and pruritus
33
Q
Dermanyssus gallinae (poultry red mite)
VECTOR!!!
A

Most time spent off host in dark cracks and crevices in housing or in nests
Adults and nymphs ‘attack’ birds at night to feed on blood
Rapid population growth
can cause massive infestations
Cause pruritus and inflam, anaemia, red prod, death
Adults can survive long periods in empty sheds
Transmit borreliosis and spirochaetosis

34
Q

Ornithonyssus sylviarum - northern fowl mite

VECTOR!!!

A

Entire lifecycle spent on host
Red productivity due to irritation and anaemia
Transmission of fowl pox and newcastle dis
Some bite and feed on humans

35
Q

Forage mites (non parasitic)

A

Climb onto face legs or flanks of sheep providing dissem method
Occassionally cause hypersens/pruritus
Hair or wool loss over affected areas
Control is impossible
Often seen in faeces when performing worm egg counts

36
Q

House dust and storage mites (non parasitic)

A

Storage mites found on hay and grain
Cause asthma in humans following antigen inhal in faeces or on mite body
Also common cause of atopic dermatitis

37
Q

Id of parasitic v non parasitic

A

Diff mouthparts. Parasitic have feeding mouthparts and non parasitic dont