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Ectoparasites (See Old App For Images) Flashcards

1
Q

What are Arthropoda

A

Invertebrates
external waterproof skeleton made of chitin
Segmented body
Jointed limbs
Haemocoel= body cavity containing haemolymph

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2
Q

Are arthropods of vet importance permeant or temp parasites?

A

Can be both

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3
Q

How would you split arthropods

Give examples of what’s in each category

A

Insects- flies, lice, fleas

Arachnids- ticks and mites

Crustceans

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4
Q

List economic losses and welfare issues associated with ecto parasites

A 
Skin damage/invasion e.g. Sheep scab and myiasis (fly strike)
Nuisance flies- decline in milk 
Self wounding secondary infections
Inflammation/pruritis (sarcoptic mange)
Toxic and allergic reactions (FAD)
Blood loss
Pathogen transmission
Cost of treatment/control
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5
Q

What are tsetse flies a vector for?

A

Trypanosomes (in Africa)

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6
Q

How do ectoparasites grow?

A

By ecdysis/shedding under the influence of juvenile hormones

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7
Q

How many legs in:

Adult insect

Adult/nymph stage arachnid

Larval stage arachnid

A

3 pairs

4 pairs

3 pairs

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8
Q

The exoskeleton provides protection and support. What else do it have on it?

A

Hairs/bristles/spines etc.

It’s divided into plates called sclerites

Muscles are attached to the inside of it

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9
Q

What does the nervous system consist of?

A 
Ganglia (brain)
Sensory organs (e.g. Eye)
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10
Q

How do they perform respiration

A

Via openings in the protective cuticle

Spiracles in insects/stigmata in ticks and mites

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11
Q

What does the GI tract consist of?

A

It’s a simple tube from mouth to anus

Feeding mouthparts- foregut/proventr (food broken up)- midgut (store and digest) - malpighian tubules (where waste from haemocoeal filters into gut) - hindgut (water absorption)

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12
Q

How many body regions in insects

Which do the legs come from

Do they have wings? Antennae? Specialised mouthparts?

A

3- head, thorax, abdomen

Legs from thorax

Can have wings, have 2 antennae and have specialised mouth parts

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13
Q

How many body segments in arachnid

Do they have wings/antennae?

A

2 - cephalothorax and abdomen

No

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14
Q

Do both insects and arachnids have specialised mouthparts e.g. Pool feeders and sponging mouthparts?

A

Yes

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15
Q

What are the two types of life cycle in ectoparasites- which undergoes each??

A

Holometabolous- complete metamorphosis = flies

Hemimetabolous - incomplete metamorphosis- lice and ticks

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16
Q

Explain the differences with these life cycles

A

Holo e.g. Insects have 4 stages. Egg, larvae, pupae, adult. Wings develop inside body

Hemi e.f. Ticks have 3 stages, egg, nymph, adult

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17
Q

How do ticks reproduce?

A

Via a spermatophore- a capsule surrounding a mass of spermatozoa produced by the male in various animal species and transferred to the female

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18
Q

How do flies reproduce

A

Females must obtain protein to mature their eggs. This is why they pester cattle and why Mosquitos suck blood

The female is fertilised and then lays her eggs

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19
Q

What does the order Diptera mean?

A

Insects

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20
Q

What is the difference between ticks and mites?

A

Ticks possess a toothed hypostome

Mites do not

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21
Q

What kind of feeder are ticks

Why are they so important

A

They are obligate blood feeders

They are important as disease vectors

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22
Q

What do mites feed on? E.g. Sarcoptes

What do they cause?

A

Skin scales, lymph exudate and fluid

Mange

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23
Q

Give an example of a non burrowing mite

A

Psoroptes ovis (sheep scab)

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24
Q

Give an example of a follicle dwelling mite

A

Demodex spp.

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25
What sort of things have caused ectoparasites to be a modern growing problem that need controlling?
``` Intensification of animal husbandry High livestock densities Global transport of humans and animals Artifical selection towards greater susept to infest Modern home environments Growing reservoirs e.g. Protected deer ```
26
Why do we need to control ectoparasites?
``` They cause ... profit loss Ill health Poor condition/weight loss/irritation/dermatitis Hide and fleece damage Transmit disease Vectors for zoonotic disease ```
27
What are seasonal trends seen in ectoparasites?
Nuisance flies are a summer issue, they develop in the environment. Flies cause fly strike in late spring/early summer. Ticks are also a summer issue- there numbers are greatest in May/June Fleas are an issue all year round but mainly summer Lice and mites are a winter problem
28
What are the approaches to control?
Chemical control 'on host' dominated by insecticides/acaricide Several "off host" approaches e.g. Sprays/traps Integrated pest management is a combo of chemical control on and off host. Combining insecticide use with environmental control. Non chemical uses also e.g. Ensuring hygiene of fomites, reduction of exposure e.g. House animals or quarantine (chemical, environmental, fomites,quarantine)
29
What are basic preparations? What advances are there for targeted control? What special considerations must be taken into account?
Chemical/non chemical/environment/topically/systemically Advances: pour on/spot on/collars/ear tags Can give orally, parentally or topically Need to bare in mind environmental or contamination toxicity and also safety margins and meat withdrawal periods
30
Name the major classes of ectoparasitacides
``` Organochlorines Organophosphates Synthetic pyrethroids Macrocyclic lactones Insect growth regulators ```
31
What was the big issue with organochlorines?
Led to widespread resistance in Mosquitos Went into the food chain via birds and had a bad environmental impact Hence banned in 1984
32
How do organophosphates work? Why are they relatively toxic to humans?
They mimic ACh, leading to accum of insect neurotransmitter, cause paralysis and death Because they are so lipid soluble
33
Give an example of a organophosphate still used today??
Diazinon Used as sheep dip to control mites/lice/blowfly for at least 60 days
34
What is permethrin cypermethrin?? How does it work? List some qualities it has
It's a synthetic pyrethroid It works by exciting cell membranes, causing depolarisation and paralysis Photostable, high potency, broad spec, many preparations, effective against flies/lice/ticks
35
Name the 2 broad types of ML?? Give an example of each
Avermectins e.g. Ivermectin Milbemycins e.g. Milbemycin oxime
36
What do MLs do? What are they effective against?
Inc GABA binding, inc CL into cell, cause hyperpolarisation and flaccid paralysis Wide range of arthropods and nematodes
37
Why do MLs not effect mammals?
GABA neuro transmission is only in CNS in mammals. The large ivermectin molecules does not readily cross blood brain barrier
38
What other good qualities do MLs have? What do we need to bear in mind?
They are highly lipophilic, so are stored in fat, slow released and persistent and therefore provide extended protection (longer when give IV or sc) Withdrawal periods, oral admin very little effect against mites which cause sheep scab
39
Which breed must you never give ivermectin to?
Collies Genetic mutation meaning it can cause BBB and lead to CNS symptoms
40
What are insect growth regulators used for? What do they do?
Immature stages (used for blowfly larvae and flea control) They can be chitin inhibitors so prevent chitin/exoskeleton development. Or they can be juvenile hormone analogues and so again prevent growth
41
Give an example of a chitin inhibitor
Diflubenzuron
42
Give an example of a juvenile hormone analogue
Methoprene
43
Give trade names for these (may help remember what effective against) ``` Imidacloprid Fipronil Amitraz Afoxolaner Fluralaner ```
``` Advantage Frontline Alludex Nexguard Bravecto ```
44
What does imidacloprid do? What does it target? Bad points?
Binds to nAch receptors leads to paralysis and death Adult fleas only High bird toxicity/neg impact in bee pop
45
What does fipronil do? What's it effective against? Bad points?
Blocks GABA transmission. Lipophilic so diffuses into Seb glands acts as reservoir Fleas and ticks Long redid activity, toxic to fish and bees
46
What does amitraz target?
Ticks and mites
47
Which animals can you not use amitraz in?
Horses and cats
48
What do afoxalaner and Fluralaner treat for
Ticks fleas | Also Demodex??
49
What do the flies in the muscidae family feed on?
Secretions or suck blood
50
What's myiasis
When flies lay eggs on animals and larvae invade and feed on tissue (fly strike)
51
Whic muscidae fly is biting? Which is strange for this family
Stomoxys calcitrans (the stable fly)
52
Why is this fly important
When it heavily infests cattle it lowers milk production Bites humans. In some parts of the world it is a vector for trypanosomid parasites.
53
Describe the life cycle of a muscidae fly
Complete metamorp with 4 stages Over winters in larval/pupae stage under manure piles Summer conditions optimum for development. Completes life cycle in 7-10 days. Dispersed to other livestock in pasture
54
Where do flies rest and mate
Warm sun exposed surfaces eg gates etc.
55
Where do flies prefer to feed in the animal?
Lower parts especially legs and flank
56
Give some host responses to this
Stamping feet Shivering of skin Sudden turning of head Tail swishing
57
Stomoxys calcitrans causes what problems?
Fly worry Pathogen transmission - equine infectious anaemia, trypanosomes, and others such as anthrax and BVD Aare suspected
58
Name 3 non biting muscidae
Head fly, face fly and house fly Hydrotaea irritans, Musca autumnalis, Musca domestica
59
What does hydrotaea irritans pester
Cattle, sheep, horses and man
60
Where does the headfly deposit eggs? How many generations of flies do you get each year.
Pasture soil Only 1
61
State some behaviours of the headfly
Doesn't enter buildings Found around livestock and us Typically on wooded pasture Most numerous on overcast, warm, humid days in August
62
State some host behaviours in response to the headfly
Rapid head turn | Tail swishing
63
Hydrotaea irritans congregates around the corner of eyes and around ends of udder tears, why is this a problem
Transmits agents of summer mastitis Fly worry but not as dramatic as biting spp
64
Whic livestock does Musca autumnalis mostly effect
Cattle and horses Found on face muzzle and eyes (hence name face fly)
65
Key points for the lifecycle of the face fly
Don't enter buildings Develop in dung, hatch quickly, larvae feed on microbes in faeces, emerge (temp dependent) Populations build up in autumn
66
What diseases is the face fly associated with?
Pink eye in cattle: infectious bovine keratoconjunctivitis caused by moraxella bovis Likely to cause similar in horses Also vector of thelazia (eye worms) and habronema (stomach worms)
67
What's the main significance of them in the UK though
Nusicance
68
Where is the face fly found most?
Southern England not northern
69
What tumours are flies thought to be vectors for?
Sarcoids
70
Name 2 biting fly NOT in the family muscidae of vet importance
Tabanus and haematopota These are both 'tabanids'
71
Where do tabanids breed?
Wet pasture, marshy land next to lakes/ponds
72
What are the significance of tabanids??
``` They gad (move around most) on sunny days in July and August. They take several small meals. Vectors for EIA, anthrax, trypanosomes and bovine anaplamosis (blood parasite) ```
73
What are culicoides
Biting midges
74
Life cycle of biting midges...
Dig a hole and feed on free blood Eggs laid in damp compost heals, decaying veg, and marshy land Egg to adult in less than 3 weeks 1-2 generations a year
75
What's the significance of biting midges?
Irritation Cause sweet itch in the UK Also cause seasonal recurrent allergic dermatitis = a pruritic hypersens reaction to saliva Cause animals to have self inflicted lesions
76
What pathogens do biting midges transmit
African horse sickness Blue tongue Schmallenberg virus
77
What genus is the virus African horse sickness in?
Orbivirus
78
Simulium spp are black flies. State their life cycle
Lay eggs on stones in running water Aquatic larvae Adults active most in morning and evening Live up to 4 weeks feeding on horses and cattle
79
What diseases are back fly associated with?
Leucocytozoon to ducks/geese Non pathogenic onchocerca spp = horses and cattle (roundworm) Greatest importance in west America and South America where they cause human onchocerciasis (river blindness)
80
How are flies controlled on liveries and farms
Integrated pest management approach Use of insecticides (mainly synthetic pyrethroids) as ear tags, pour one and sprays Treatment of resting surfaces Habitat and husbandry management: dung is moved from inside housing, but need to bear in mind population dispersal if used as fertiliser. Barrier methods: head masks and body protection on horses
81
What fly is a highly adapted parasite of horses?
Gasterophilus (the horse bot fly)
82
What does the horse bot fly cause?
Myiasis (fly strike)
83
Name 3 species of horse bot fly When are these most active?
G. Intestinalis G. Nasalis G. Haemorrhoidalis Late summer
84
Describe the life cycle of a horse bot fly g.intestinalis
Eggs laid late summer on inner forelimbs, hocks and shoulders Burrow into tongue, moults and exits. It then goes to the pharynx which can take 3-4 weeks, where it moults to L2 They then cluster in the oesphageal portion of the stomach They moult to L3 and remain in the stomach until spring when they are passed during faeces in June
85
How many generations of bot fly in 1 year?
1
86
Nasalis and haem. Are of lesser importance, where do these ones migrate to?
Pyloric part of stomach Attach to rectum
87
Do bot flies cause disease?
Surprisingly only occasionally. Can form crater like ulcers, inflammation and large maggots are seen in faeces which freaks out owners
88
How do you diagnose bot fly?
See larvae in faeces in spring Eggs on coat in summer
89
How do you treat bot fly?
Remove eggs Anthelmintics (moxidectin = ML)
90
Which part of the arthropod section are mites in?
Arachnids
91
Define mange
A skin disease caused by parasitic mites characterised by itching, hair loss and formation of scabs and lesions
92
Can non burrowing and burrowing mites cause mange?
Yes

Year 2 Parasitology (1 decks)

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