Ectoparasites Flashcards by Caitlin Marscham

What are the characteristics of those organisms in the phylum ARTHROPODA

chitonous exoskeletons
Internal musculature
separate sexes
moults between stages

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What are the classes under ARTHROPODA?

Insecta (Diptera-flies, phthiraptera =lice, siphonoptera-fleas/other-cimex)
Arachnida (A-,pro-, meso-stigmata (mites)/ metastigmata (ticks)
other (crustacean/pentastomida)

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What make up the class INSECTA?

flies (Diptera), lice (Phthiraptera), fleas (Siphonoptera) and other (bed bugs Cimex)

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What is the anatomy of those that make up INSECTA?

Head, Thorax (3 segments) and abdomen (8-10 segments)
3 pairs of legs
1 pair of antennae
only arthropods to possess wings

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How many legs do those organisms classified as INSECTA have?

6 always!

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The order Phthiraptera refers to what?

lice (singular louse)
‘aptera’ means no wings
- dorsoventraly flat

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What are the 2 suborders in the order Phthiraptera?

Arthropoda -> Insecta -> Phthiraptera

Anoplura (sucking lice) = mouth parts penetrate skin feeding via sucking body liquids -> Topical insecticides less likely to work
Mallophagia (Biting lice) = mouth parts are not penetrating skin. feeding on keratin and superficial layer of skin -> topical insecticides work

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What are some characteristics of the sucking louse?

Narrow/relatively elongated head (head evolved to pierce through skin and feeding on fluids)
horse, pig, cattle, sheep, dog
often specific to a site on a host
v host specific
cosmopolitan, increase in winter
highly pathogenic

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What are some characteristics of biting lice?

“chewing lice” or “body lice”
Broad and rounded head as wide (or wider) as the thorax
Areas of fine hair
smaller (<3mm)
Pale in colour
Keratin feeders
Cosmopolitan
dog, cat, sheep, cattle, horse, poultry
generally less/non pathogenic but cause kyperkeratosis
Bovicola ovis is in sheep fleece and affects wool growth and is of significant economic impact

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Bovicola Ovis is what type of parasite?

Biting louse

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What is the order SIPHONAPTERA commonly known as?

fleas

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Characteristics of the order Siphonaptera:

wingless (‘-aptera’)
Feed by inserting their mouthpart directly into capillary and then “siphon” out blood
laterally compressed
3rd pair of legs adapted for jumping

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What flea is a major cause of skin problems in dogs & cats?

Ctenocephalides felis (Cat flea)

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What is the most resilient stage of the flea life cycle?

Pupa

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Outline the lifecycle of a flea?

female needs blood to lay eggs
Eggs drop into the envt
Maggot-like larva feeds on detritus (inc. flea faeces)
Pupa = highly resilient stage
Only 5% of fleas are on the host, 95% is in the environment (eggs, larvae, pupae)

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What is the common name of those organisms that fall into the order Diptera?

Flies, midges, mosquitoes

means “2 wings”

Musca; Stomoxys, Haematobia

are what?

small grey to black flies, 5-10mm
flies with sucking mouth parts = ‘Musca’
Flies with biting mouth parts = ‘Stomoxys, Haematobia’
Musca cause ‘fly worry’ when feeding around eyes; mechanical vector of bacteria
e.g. Stomoxys calcitrans = stable fly
Haematobia exigura = Buffalo fly

What are the genus’ of blow flies (the family calliphoridae)(order Diptera)

Lucilia
Calliphora
Chrysomya

What is the major fly genus causing flystrike in sheep?

Lucilia cuprina

- coppery green thorax and abdomen

Which fly is not an ectoparasite?

bot flies (oestridae)

Gasterophilus (horse bot)
Oestrus (sheep bot)
Hypoderma (cattle bot)

What are some characteristics of the Oestridae family of flies?

bot flies
called so because their 3rd larval stage looks like a bot
adult flies are hairy and large (bee-like); they are harmless and cannot feed (no mouth parts)
Larval stages = PARASITIC
Not highly pathogenic

What are some characteristics of the class ARACHNIDA?

(Astigmata-mites; prostogmata-mites; mesostigmata-mites;metastigmata-ticks)

Parasitic (mites/ticks)
Body divided into 2 parts only: Body (idiosoma) and Head (capitulum or gnatosoma)
Groups are differentiated based on spiracles/stigmata (resp pores)
4 pairs of legs on body (except larva only have 3 pairs)
no antennae/wings

How many legs do organisms that belong to the class ARACHNIDA have?

4 pairs of legs on body

except larva only 3 pairs

What are the Metastigmata (also called Ixodidae)?

Hard ticks:

Ixodes
Rhipicephalus
Haemaphysalis

there are also ‘Argasidae’ = soft tick

What organisms are from the suborder Prostigmata?

Arachnida --> Prostigmata - mites - "trombiculids" (trombicula, eutrombicula, neotrombicula) - Larval stage = parasitic (3 pairs of legs) - Larva attach to skin = highly irritating and pruritic - Can be vectors of scrub typhus (Orientia australia) - Nymphs and adults are free living predators 1. Psoregates ovis (sheep itch mite) - small (<0.2mm) - mainly problem in Merino sheep - causes hypersensitivity reactions leading to biting and rubbing (fleece degradation) 2. - Cheyletiella parasitovorax on rabbits - Cheyletiella yasguri on dogs - Cheyletiella blackei on cats - distinguishing feature is a large "claw" - called "walking dandruff", they are large and seen on fur - cause mild dermatitis with hyperkeratosis - human infection can occur 3. Demodex spp. - Demodex canis - significant in dogs (demodectic mange & serious skin disease) - Demodex bovis - damages hides (other spp. are of lesser importance, but almost all mammals have their own sp.) - Small (<0.3mm) mites, elongate (very typical cigar shape; exception to the fir tree-like rule - Mites found in hair follicles and sebaceous glands - Most dogs are infected, only a few develop disease

What are the organisms of the suborder Astigmata?

- 'mange mites' often cause skin disease - anterior two leg pairs separated from the posterior 2 pairs 1. Birds: - Knemidocoptes - Cytodites 2. Mammals: - Sarcoptidae (legs don't project beyond body) * Sarcoptes * Notoedres - Psoroptidae (legs DO project beyond body) * Psoroptes * Otodectes * Chorioptes

What are the common ear mites of dogs and cats (also fox and feret) from the Suborder Astigmata?

Arachnida --> Astigmata --> Otodectes cynotis - cause mild ear otitis externa - similar to psoroptic mites - occur in external auditory meatus

What is the name of the burrowing mite that has a wide range of hosts with adopted strains causing 'sarcoptic mange'?

Astigmata -> Sarcoptes scabei (Sarcoptidae) - small mite, with triangular scales - Significant in pigs, dogs, humans (scabies) and many native animals (wombats) - Burrowing mite, in s. corneum (females lay eggs)

What are the main features of the order ACARINA; suborder METASTIGMATA?

- 8 legs (8 in nymphs; 6 in larvae) - Scutum - Capitulum - Leathery, folded exoskeleton allows for expansion during blood engorgement - Hard ticks (Ixodid) have anterior mouthparts and a visible scutum vs; - soft tix (Argasid) have ventral (downward) mouthparts and lack a scutum

What are the main ticks in Australia? (know for midsem)

1/ Paralysis tick (Ixodes holocyclys) 2/ Bush tick (Haemaphysalis longicornis) 3/ Cattle tick - more QLD (Boophilis australia) 4/ Brown dog tick (Rhipicephalus sanguineus)

What are the main features of mites?

- 8 legs (6 in lymphs) - Stomata - Coxae - Pedicles - Setae (hairs) - lobes - Chelicerae (piercing mouth parts)

Where can you find mites on an animal?

- on the surface of skin (e.g. Cheyletiella) - in hair follicle (e.g. Demodex) - in tunnels of the skin (e.g. Sarcoptes)

Give at least 1 example of a sarcoptid mite (from suborder: Astigmata)

1. Sarcoptes scabei - scabies in dogs, humans, pigs, wombats, foxes 2. Notoedres cati - mange mite of cats 3. Otodectes cynotis - ear mite of dogs and cats 4. Chorioptes bovie - mange in cattle, horses, sheep 5. Psoroptes communis - bite and suck causing irritation (non-burrowing) in cattle, sheep (not aust) & horses 6. Cnemidocoptes - bird mites e.g. beaks and clawa 7. Trixacarus caviae - intense pruritus in guinea pigs