Intro to ectoparasites Flashcards
What are the features of a true parasite?
- evolutionary advanced organisms
- complex lifecycles
- intermediate hosts
What is ‘Commensals’?
-the host and parasite tolerate each other (don’t cause harm)
What is ‘Symbiotes’?
-the host and parasite work together- mutually beneficial
What is an example of a micropredator?
-mosquito
What are the different types of ectoparasite?
- Arthropods
- 85% of all animals
- jointed legs/ limbs
- exoskeleton (chitin)
- cold blooded
- seasonal/ semipermanent parasites
- Acari
- mites
- ticks
- Insects
- lice
- fleas
- flies
- Crustacea
- fish ‘lice’
What are obligate and facultative ectoparasites?
- Obligate - completely parasitic
- Facultative- can be free-living or parasitic
What is the difference between permanent and semi-permanent ectoparasites?
-Permanent
- spends entire life-cycle on host
- passive spread host to host
- treat host
-Semi-permanent
- spends part of lifecycle off the host
- actively seeks host
- treat host and/or environment
Example of permanent ectoparasite?
-lice
Example of semi-permanent ectoparasite?
-fleas
Where do ectoparasites live on the host?
-skin
How to ectoparasites damage skin?
- blood feeding
- directly- though feeding
- indirectly- allergic response
What are the clinical signs an animal has ectoparasites?
- anaemia
- prutitus (itching)
- rubbing and scratching
- scab lesion- allergic reaction
- traumatic wounds
- hair balls (excessive grooming)
- structural damage (excessive rubbing)
- loss of body condition
What can Pruritus be induced by?
- mechanical stimuli
- physical activity of parasite
- sensation recieved by free nerve ending in skin
- allergic reaction
- cuticle, secretions, excretions
- bites
- stings
What is hypersensitivity?
- enhanced state of responsiveness following sensitisation to a particular antigen
- releasing pharmacologically active substances e.g. histamine, dilating blood vessels, increaing permeability
- allowing fluid and cells of the immune system to leak from bloodstream and migrate to tissue injury
- in hypersensitivity- mast cells release histamine in inordinate amounts (results in acute pruritis
What can induce pruritus?
- substance P
- cytokines
- proteases
- histamine (main)
Problems associated with ectoparasites?
- Animal welfare issues
- loss of production
- Expensive/ controversial control methods
- human/animal toxicity
- environment
- withdrawal periods
What ectoparasites are host specific?
-lice
Which ectoparasites have low host specificity?
- fleas
- mites
Name the different types of host
- Clinical host (adverse effects presented)
- Reservoir host (no apparent adverse effects)
- Transport host (increase ectoparasite survivability off the clinical/reservoir host, no adverse effects)
What is the class and subclass for mites and ticks?
- Class - Arachnida
- Subclass - Acari
What is contained in the superorder Acariformes?
- Astigmata
- free-living
- fungivorous
- mites
- ecto/endo
- Prostigmata
- free-living and parasitic
- Oribatidae
- free-living soil dwellers
- intermediate hosts of mammalian tapeworm spp
What is contained in superorder Parasitiformes?
- Mesostigmata
- free-living
- fast moving
- ecto
- Ixodida
- ticks
- high specialised blood feeders
What are parasitic mites classified according to?
- the presence and position of the stigmata and peritreme
What do the respiratory systems comprise of?
- internal trachea
- opening to a pair of stigmata (spiracles)
What is the peritreme?
- the stigmata often extend anteriorly into an open canal/ groove (peritreme)
Describe the respiration of Astigmata
- stigmata, peritreme, tracheal system all ABSENT
- breath through cuticle
Describe respiration of Protigmata
- breathing cord under the head
- stigmata located on gnathosoma (mouthparts)
- peritreme ‘M’ shaped
Describe respiration of Oribatidae (Cryptostimata)
- stigmata hidden from view
Describe respiration of Mesostigmata
- long breathing canal (can live in dry environments)
- one pair stigmata located laterall in region of coxae II and III
- petriemes run laterally down side of mite
Describe respiration of Ixodida (Metastigmata)
- stigmata situated on ventrolateral surfaces
- posterior to coxae IV on a spiracular (stigmatic) plate
What is this?
-Prostigmatid mite
What is this?
-Mesostigmatid mite
What is this?
-Oribatid mite
Describe the lifecycle of an Astigmatid mite
- egg
- larva (6 legs)
- protonymph (8 legs)
- tritonymph (8 legs)
- nymphs are not sexually dimorphic
- adults are males and females
- mate
- female moults into egg laying stage (ovigerous)
- male mates again
What is the lifecycle length of Chorioptes bovis?
-21 days
Lifecycle length of Psoroptes ovis?
-14 days
Is this mite male or female?
-female
Is this mite male or female?
- male
- has suckers at the bottom
Name the non-burrowing mites
- Astigmata
- Otodectes
- Chorioptes
- Psoroptes
- Prostigmata
- Chyletiella
Name the burrowing mites
- Astigmata
- Sarcoptes
- Notoedres
- Trixacarus
- Cnemidocopters
- Prostigmata
- Demodex
- Psorobia
What are the results of Mange (Scabies)?
- Traumatic damage (burrowing, feeding, scratching)
- Allergic dermatitis
- salivary secretions
- sloughed skin (exuvia)
- excreta (guanine)
- peritrophic membrane (around excreta) - passes out as envelope
What is Transient Mange?
- caused by free living Astigmatic mites
- feed infested with mites (swarm over head)
- tempory (good food hygiene)
What is Sarcoptic Mange?
- -Sarcoptes scabiei
- burrowing Astigmatid mite
- infest wide range of hosts
- Genotypic similarities (ITS-2 of mRNA)
- zoonotic
What has caused this?
-S.Scabeie var ovis
What has caused this?
-S.Scabiei var suis
What type of mange is shown?
-Alopecic mange
What type of mange is shown?
-Hyperkeratotic mange
What is Demodex?
- found in most mammalian species
- canine = red mange
- thick scabs
What causes Psoroptic mange?
- Psoroptes spp
- non-burrowing mite
- wide range of hosts
- phenotypic differences- L4 OOS
- genotypic similarities (ITS-2 of mRNA)
- not zoonotic
What are the different Psoroptes mites?
- P.ovis/P.cuniculi
- body/ ears of wide host range
- P.natalensis
- cattle
- body only
What does this show?
-Psoroptes ovis/ P.cuniculi
Describe the lifecycle of the 3 host tick (Ixodes ricinus)
4 stages
- egg
- larva (once fed larva and nymphs drop off host to digest blood meal and moult)
- nymph
- adult
What is this?
-tick (Ixodes ricinus)
What are the features of lice (Pthiraptera) ?
- permanent parasites
- blood sucking (vectors of disease)
- chewing
What is this?
- Lice (pediculosis)
- chewing (mallophaga)
What is this?
- Lice (Pediculosis)
- sucking (anoplura)
What are lices adaptations to parasitic life?
- dorso-ventral flattening
- head and mouthparts directed down
- reduced number antennal segements
- thoracic and abdominal spiracles
- specialised legs and claws
How would you describe the lifecycle of lice?
- incomplete metamorphosis
- mother to offspring (vertical transmission)
- shared combs and brishes (mechanical)
Describe the features of fleas (Siphonaptera)
- semi-permanent
- blood sucking
- vectors of disease
What is this?
-rabbit flea
What is used to identify flea species?
- front and back combs
How are fleas adapted to parasitism?
- laterally flattened
- antennae recessed in fossae
- head sessile on pro-thorax
- body covered in backward pointing hair (setae)
- many cases- combs (cyenidia)
- this all allows for easy movement through fur/feather
Describe the fleas found in cats
99% = Ctenocephalides felis
1% =
- Ctenocephaliides canis
- Archaeopsylla erinacei
- Pulex irritans
- Spilosyllus cuniculi
Describe the fleas found in dogs
93% = Ctencephalides felis
7% =
- Ctenocephalides canis
- Archaeopsylla erinacei
- Pulex irritans
- Ceratophyllus fasciatus
What effects do fleas have on their hosts?
- flea allergy dermititis
- anaemia
- vectors of disease
- tapeworm (dipylidium)
- cat scratch disease
- myxomatosis
- bubonic plague
- murine typhus
- human involvement
- welfare
How would you describe the lifecycle of fleas?
Complete metamorphosis
Describe the lifecycle of fleas
- Nidicolous
- adults 5%
- immature 95%
- eggs 50%
- larvae 35%
- pupae 10% (resistant stage
- may use host hormones to become pregnant themselves (rabbit flea)
Describe the features of flies
- semi permanent
- blood sucking
- secretophagous
- myiasis
What is this?
head fly (hydrotea irritans)
What is Myiasis?
- infestation of living tissue by larvae (maggots) of the true flies (Diptera)
What is this?
human bot fly
What is this?
screwworm
Name the different variations of myiasis
- Obligate
- warble flies
- horse bots
- sheep nasal bots
- Facultative
- sheep blowfly strike
- Accidental
- hover fly larvae
- crane fly larvae
What is this?
horse bot
What are the different species of horse bots?
- G.intestinalis (widely distributed, larvae burrow into mucous membrane of tongue
- G.nasalis (eggs hatch sponateously)
- G.haemorrhoidalis (eggs hatch in response to moisture)
- G.inermis (hatch spontaneously)
(migrate to stomach (56%), intestine (25%), rectum (12%)
What are the effects of horse bots?
- swelling at the point of entry
- oesophageal ulcers
- chronic gastritis
- loss of condition
What is the damage caused by oestrus ovis?
Adult flies:
- interrupted feeding
- ‘gadding’
Migrating larvae
- irritation
- catarrhal discharge
- avoidance behaviour
- secondary bacterial infections
- inflammation of mucus membranes
- preventing L3 escape
What are Hippoboscid flies?
- obligate
- permanent parasites
- often called ‘sheep tick’
- wingless
- blood sucking
- pupae attached to wool
- emerge in 2 weeks
Biting flies: what diseases are they vectors for?
- Schmallenberg virus (SBV)
- Bluetongue Disease Virus (BTDV)
