Ectoparasites Flashcards
1
Q
What are Arthropods and what are their features?
A
- largest animal phylum (85% of all known animals)
- jointed legs/ limbs, mobile
- exoskeleton (chitin)
- need to moult to grow
- target for biochemical control
- cold blooded (poikilothermic)
- seasonal
2
Q
What are the subgroups of arthropods?
A
- acari
- mites
- ticks
- insects
- lice
- fleas
- flies
- crustacea
- fish ‘lice’
3
Q
What is this?
A
- house dust mite
4
Q
What is this?
A
- poultry red mite
5
Q
What are the 2 categories of parasitic acari?
A
- permanent
- lifecycle entirely on host
- astigmata, prostigmata
- skin allergies- mange/scabies
- respiratory allergies
- semi-permanent
- part of lifecycle off host
- prostigmata, mesostigmata
- blood sucking
- vectors of disease
- skin/resp allergies
6
Q
What is mange and what is it caused by?
A
- scabies
- traumatic damage (burrowing, feeding, scratching)
- allergic dermatitis
- salivary secretions
- sloughed skin (exuvia)
- excreta (guanine)
- peritrophic membrane (around excreta) - part of gut
7
Q
What is the cause of transient mange?
A
- free living (astigmatic) mites
- feed infested with mites - swarm over head while feeding
- similar to excretory antigens to parasitic mites
- temporary - controlled by good food hygiene
8
Q
What is the cause of Sarcoptic mange?
A
- burrowing astigmatid mite
- can infest a wide range of hosts
- phenotypic differences (ITS-2 of the mRNA)
- 1 type species (sarcoptes scabiei)
- pre-adaptation
- potentially zoonotic
9
Q
How does sarcoptic mange occur? How do the mites manifest?
A
- adult females burrow into horny layer of skin
- eggs deposited in tunnels
- larvae migrate to skin surface, shelter in hair follicles and moult
- nymohs also moult in hair follicles
- adult males and females make short burrows (1mm) into the skin - mating burrows
- the adult female increases in size as her ovaries develop (300-500um)
- lays 1-3 eggs per day
- never voluntarily leaves burrow
- survive off hosr for 17 days
10
Q
How do secondary bacterial infections form in sarcoptic mange?
A
- saliva/ faeces antigenic + damage through burrowing
- infiltration of eosinophils into epidermis and dermis
- papules and vesicles form at site of infection - localised eczema, prutitus - scratching, secondary bacterial infections
11
Q
What is Hyperkeratotic scabies? What are the clinical signs?
A
- mites multiply very rapidly forming crusty (hyperkeratotic lesions)
- mites are found in their thousands
- severe itching
- large areas of skin show a crusted or scaly appearance
- highly contagious
- swelling of lymph nodes
- strong eosinophilic response - high levels of IgE and IL4
- high risk of secondary infections - fatal
12
Q
What are the predisposing factors for hyperkeratotic scabies?
A
- very old/ young
- immunosuppressive drugs
- alcoholics
- ethnic groups
13
Q
What types of mange are shown?
A
14
Q
What is Demodex?
A
- caused by prostigmatid mite
- found in most mammalian species
- host specific
15
Q
What condition is this dog presenting?
A
- canine demodecosis
- D.canis - not usually serious
- can be a cause of generalised demodectic mange
- serious inflam condition- serum, puss, blood oozing from skin surface- red mange
- secondary bacterial infections (staphylococcal) infections
16
Q
What has caused this?
A
- carnivore ear mite (otodectes cynotis)
- non-burrowing astigmatid mite
- parasite of ear canal
- cats, dogs
17
Q
What is Chorioptes bovis? What animals does it infest?
A
- astigmata
- permanent/ obligate
- non burrowing
- damage aesthetic
- not host specific
- infests sheep, goats, horses, cattle, camelids
- often asymptomatic
- certain cattle breeds = generalised mange
- continental breeds (Belgium Blue/ White)
- Highland Cattle (microclimate)
18
Q
What are the Predilection sites?
A
- base of tail
- perineum and udder
- scrotum - infertility
- lower limbs
- hooves - lameness
- ears
19
Q
What is the only form of equine mange in UK?
A
- equine chorioptic mange
20
Q
What is Psoroptic mange caused by?
A
- Psoroptes spp
- non-burrowing Astigmatid mite
- can infest a wide range of hosts on the body or in ear
- phenotypic differences- L4 OOS
- genotypic similarities (ITS-2 of the mRNA)
- 2 type species
- P.ovis/ P.cuniculi (body/ears of wide host range)
- P.natalensis- cattle, body only
- not zoonotic
21
Q
What type of mange do these animals have?
A
- psoroptic mange
22
Q
Which mite is this and why?
A
- cheyletiella spp
- characteristic claws
- prostigmatid mite
- no-burrowing
- permanent
- lives on skin surface
- allergic dermatitis
- irritation
- walking dandruff
- C.yasgui - dogs
- C.blakei- cats
- C.parasitovorax - rabbits
23
Q
What is this mite?
A
- notoedres cati
24
Q
What is this mite?
A
- trixacarus caviae
25
Q
What is C.pilae?
A
- cere of aviary birds
26
Q
What does C.mutans cause?
A
- scaly legs
27
Q
What doesnt Cnemidocoptes spp have?
A
- pegs and spine
28
Q
What is C.gallinae?
A
- depluming mite
29
Q
What is the poultry red mite and what does it cause?
A
- mesostigmata
- intensive or free range
- small scale units
- blood feeding
- lives in fabric of poultry houses
- anaemia - chicks
- vector of disease - salmonella
- reduced egg production
- reduced weight gain
- human involvement
30
Q
What is this?
A
- ophionyssuss natricis
31
Q
What are nasal mites?
A
- halarachnidae
- canine nasal mite
- inhabit nasal passageway
- heavy infection - sneezing, nose bleeds, sinusitis, mucus, reddening of nasal mucosa, cough, chronic nasal discharge
- do nasal swab, rhinoscopy, flush
32
Q
Name one host and multi host ticks
A
- One host = Rhipicephalus spp
- multi ixodes spp
- soft tick = argasidae
- hard tick = ixodidae
33
Q
Which adult female ticks are these (sheep)?
A
34
Q
What is the 3 host tick?
A
- Ixodes ricinus
- egg
- larvae
- nymph
- adult
- instar feeds every 12 months
- gives a 3 year cycle
- can be 2-6 years
35
Q
The egg?
A
- several thousand layed
- 2 will survive
- wax - stop being dried out
- hatching
- spring - 16-48 weeks
- autumn - 21-28 weeks
36
Q
Describe the larvae of Ixodes ricinus
A
- found in clumps in vegetation where mother died
- seed ticks - 6 legs
- breathe through skin - cuticle
- return to humid layer if fail to find host
- feed off small mammals and birds
- fall off into veg
- digest blood meal and moult
37
Q
Describe the nymphs of the ixodes ricinus
A
- larger
- 8 legs
- breathe through spiracle/ trachea
- feed on larger mammals - lambs
- feed for 4-8 days
- drop off into vegetation - spread further
- digest blood meal and moult
38
Q
What is the difference between male and female adult l.ricinus ticks?
A
- females - engorge with blood
- males - feed but do not engorge
39
Q
What is questing?
A
- finding a host
- several weeks
- triggered by - increased day length and temps above 7
- attracted to co2, heat, volaltile chemicals
- cant survive more than 1 season without feeding
- Hallers organ - 1 st pair of legs
40
Q
Where are the feeding sites of ticks in sheep?
A
- climb on via head/ legs
- where there are vessels close to surface
- inguinum
- axilla
- ears
- stay on for 6-13 days until engorged
41
Q
Describe the prevalence of ticks
A
- need moisture
- found in moisture retaining ground e.g. rough grazing, moorland
- dependent on climate
- becoming more abundant
- deer
- climate change
- acaricide
- farming practises
42
Q
How are lice adapted to parasitic life?
A
- dorso ventrally flattened
- mouth part and head facing outwards
- thoracic and abdominal spiracles
- adapted legs and claws
- reduced number antennal segments
43
Q
Desctibe the life cycle of lice
A
- incomplete metamorphosis
- 3 nymph stages
- no sexual dimorphism
44
Q
Why are lice permanent ectoparasites?
A
- low powers of survival off the host
- small chance of finding new host
45
Q
How does spread of lice occur?
A
- horizontal
- vertical
- brushes etc
46
Q
What are mallophaga?
A
- chewing lice
- well developed head and mouthparts
- killed by contact insecticides not systemic
47
Q
What are these?
A
48
Q
What are Anoplura?
A
- blood sucking lice
- thin head and mouth piece - piercing and sucking
- haematopinus - pig, bovine, equid
- linognathus - bovine, equids, goats, sheep, dogs
- solenopotes capitallus - cattle
49
Q
What is this?
A
- rabbit flea
50
Q
Describe some features of fleas and their adaptations
A
- vectors of disease
- semi-permanent
- blood sucking
- laterally flattened
- antennae in fossa
- head - sessile in pro-thorax
- backwards facing hairs - setae
- combs
51
Q
What fleas infect cats?
A
- 99% ctenocephalide felis
- 1% ctenocephalide canis
- archaeopsylla erinacei
- pulex irritans
- spilopsyllus cuniculi
52
Q
WHich fleas affect dogs?
A
- 93% ctenocephalide felis
- 7% ctenocephalide canis
- archaeopsyllus erinacei
- pulex irritans
- spilopsyllus cuniculi
- ceratophyllus fasciatus
53
Q
What are fleas effect on host?
A
- flea allergy dermatitis
- anaemia
- vectors of disease
- cat scratch disease
- tapeworm
- bubonic plague
- marine typhus
- myxomatosis
54
Q
A
55
Q
What is the fleas lifecycle?
A
- complete metamorphosis
- adults - 5%
- immature - 95%
- eggs - 50%
- larvae - 35%
- pupae - 10%
- pupae = resistant stage
56
Q
What flea uses host hormones?
A
- rabbit flea
57
Q
How do fleas feed?
A
- Ct.felis - feed every 12 hours
- feed to repletion in 10 mins
- take in 7ul of blood - double in size
- oviposition in 48 hours of feeding
- saliva:
- anticoagulant
- spreading agent
- low mol weight compounds
- immune response
58
Q
What is FAD?
A
- flea allergy dermatitis
- flea bite:
- central spot
- halo around it
- not much swelling
- dogs more allergic to saliva
- subsequent bites - inflam reaction
59
Q
Specific signs of FAD in cats and dogs?
A
- dogs:
- papular eruptions - spots - on trunk, base of tail, thighs
- crusting/ scabs - self traums
- acute pyotraumatic - neck and base of tail
- bacterial dermatitis and folliculitits
- cats
- groom out most
- less fleas
- 3 conditions:
- papulocrustous dermititis
- facial alopecia
- eosinophilic plaques
60
Q
How to diagnose fleas?
A
- flea dirt
- black, comma shaped specks
- put paper towel under animal and rub
- black dots on towel
- then dampen - dissolve to red-brown liquid
- itching
- restless and scratching
- cats may show no signs
61
Q
What is the pupal window?
A
- time it takes for adult to emerge
62
Q
What are fleas?
A
- semi-permanent
- adults
- parasitic
- micropredators
- blood sucking
- secretophagous
- larvae
- parasitic
- myiasis
63
Q
Which fly is this? (secretophagous)
A
- head fly - black cap
- uni-voltine - 1 brood a year
- in pine forests
- feed on body secretions
- mouth
- eyes
- udders
- blood after horse fly
- larvae are carnivorous
- vectors of disease
- emerge June - Aug
- mastitis in summer
64
Q
What effects does the head fly have?
A
- annoyance
- reduced feeding, reduced weight gain
- damage
65
Q
What are face flies? (secretophagous)
A
- feed on body secretions
- mouth,eyes,udder
- larvae - feed on dung
- multi-voltine
- vectors
- eye worms
66
Q
WHich fly is this and what does it cause?
A
- face fly
- eye worms (thelazia spp)
67
Q
Which fly is this?
A
- horse fly
- blood sucking
- uni-voltine
- larvae - moist ground - water meadows
- only females feed on blood
- emerge june -sept
68
Q
Which fly is this?
A
- stablefly
- blood sucking
- multo-voltine
- larvae - manure
- emerge march-november
- both sexes feed on blood
69
Q
What are these blood sucking flies?
A
- mosquitos and midges
70
Q
Which fly larvae undertake myiasis?
A
- obligate
- warble flies
- horse bots
- sheep nasal bots
- faculative
- sheep blowfly strike
- accidental
- crane and hover fly larvae
71
Q
Describe the lifecycle of the warble fly of cattle
A
- adult - may, june, july
- lays eggs on hair - may-june
- larvae migrate through skin 7-9 months
- emerge on the back of cow dec-june
- stay for 1-2 months
- then marble grub falls off onto ground
- develops into pupa stage - 1-3 months then hatches
72
Q
What is this showing?
A
- damaged leather by the warble fly
73
Q
Which fly is this?
A
- horse bot
- gasterophillus spp
74
Q
What are the species of horse bot (gasterophilus) and where do they enter?
A
- G.intestinalis - spread of L1 larvae, invade mucous membrane and burrow in tongue
- G. nasalis - hatch sponataously - mouth
- G. haemorrhoidalis - hatch in reponse to moisture - lips
- G. inermis - spont. burrow into cheek
- 56% - stomach, intestine 25%, rectum 12%
- effects - oesophageal ulcers, swelling at point of entry, chronic gastritis, loss of condition
75
Q
What is this fly?
A
- nasal bot fly
76
Q
WHich larvae are these, at what stage?
A
- 1st and 3rd instar
77
Q
What is causing this?
A
- sheep nasal bot fly
- causes interupted feeding and gadding
- irritation - hooks, excreta
- catarrhal discharge, sneezing
- avoiding behaviour
- secondary bacterial infections
- mucous membrane inflammation - prevent L3 escape - die in situ
78
Q
Oestrus ovis: clinical signs/ host age?
A
- more larvae in younger sheep
- symptoms more pronounced in older sheep
- acquired immunity
- clinical signs due to immune response
- generally no rise in temp
- whole flock treatment not advised - resistance
79
Q
What is sheep blowfly strike?
A
- major welfare problem
- flies dont know farm lines - part of normal fauna
- initial - green bottle - l.sericata
- semi-permanent
- if not treated 3.7-5% lambs struck
- secondary by blue bottles - Calliphora erythrocephali - attracted to smell of original lesion of L.sericata
- continous waves
80
Q
Describe the adult attraction phase of blowfly strike
A
- only pregnant L.sericata are attracted
- by moisture and decaying matter
- not all attracted
- 10% = foot, horn, wound
- 30% = body
- 60% = breech
- breech - starts with eggs layed on tail head - treat
81
Q
Describe bowfly oviposition
A
- L.sericata are attracted to chemicals - ammonia on sheep - lay
- eggs hatch in 24 hours
- need 70-90% moisture for 14 hours to survive
- hot dry weather then heavy rain
82
Q
Describe the sheep phase - development
A
- larvae migrate down to the skin - usually in the middle of the fleece staple
- hooked mouthparts and saliva - eat into sheep
- exudate released wets the fleece and also attracts other flies
- tertiary strikes
83
Q
How does toxicity occur in sheep phase?
A
- lipid soluble faecal material of larvae are absorbed through the skin - by passes normal de-toxification
- damage vital organs
- quick death
84
Q
Prevention of blowfly strike?
A
- dagging
- tail docking
- shearing
- remove dead animals
- control foot rot
85
Q
What are hippoboscoid flies (sheep keds)?
A
- permanent, obligate
- blood sucking
- wingless
- sheep tick
- eggs and larvae develop in female
- 3rd instar larvae develop into pupae after depostion
- attach to wool
- emerge in 2 weeks
86
Q
A
