Demodex Flashcards
What are the tyupes of mites causing Demodex
Prostigmatid
Mesostigmatid
Metastigmatid
What species are included in the prostigmatid?
Demodex: inside skin, feed on sebaceous secretions
Cheyletiella spp: hair coat
Chigger mites of which there are many species e.g Neotrombicula autumnalis: larvae feed only ONCE on the skin of hosts
What species are included in the Mesostigmatid species?
RED MITES
Dermanyssus- feed on the blood of birds
What species are included in the Metastigmatid species?
Argasisae and Ixoxidae ticks
General morph of demodex
4 pairs of short legs Elongated/banana-shaped Colourless/transparent Striated hind body (opisthotone) No hairs or plates on the body Short mouth
In general about demodex
Are normal inhabitants of the skin
If animal has poor immune system they over porduce=demodicosis
Have sharp, pointed eggs (like bloodflukes) that allow them to penetrate tissues
Offspring can be infected via the mothers milk
Can leave hair follicles and walk around the skin at night
Species of demodex (7)
equi- alopecic papules caballi- harmless! on eyelids bovis- nodules caprae- papules ovis- seborrhea aries- seborrhea in genital region phylloides- papules in pigs
Demodicosis of dogs
Localized/ aquamous
Generalized/ pustular
Pododemodicosis
Localized/ squamous
Circumscribed alopecia
Seborrhea around the eye and muzzle
Generalized/ pustular
Continuous lesions on the body
Usually accompanied by pyoderma
Pododemodicosis
Distal legs
Demodicosis of cats
Same as for dogs but may also cause otitis externa
Walking dandruff
Predatory mites
Feed on keratin
Dorsal parts of animals
Causes of walking dandruff in dogs cats and rabbits
Cheyletiella:
- yasguri: dogs
- blakei: cats
- parasitivorax: rabbits
Morphology of Cheyletiella
Thickened palps with CLAWS Praetarsus has comb White/colourless body Sparsely scattered hairs Dorsal plate: scutum
Larvae mites/ HArvest mites/ CHIGGER mites
Predatory
Live in soil
Only the LARVA feed on the tissue fluids of vertebrates by injecting saliva into the skin and then using their stylostome to suck it out
- therefore only the larvae are parasitic, the nymph and adults are predatory
Holes in the skin remain
General morph of Larvae mites
Bright orange/red
Short palps (but are longer than the demodex sp)
Scattered, dense haircoat
Claws on tarsus
Dorsal plate= scutum
Larvae: hairy, 3 pairs of legs and are often attached to the keratinous part of the skin
Red mites of Po
Mesostigmatid
Blood-sucking at NIGHT, hide in cracks during the day as they don’t like light
Dermanyssus sp are temp on hosts
Can cause anaemia
General morph of red mites
Dark red/ Black body Long legs Long/cyclindrical palps V. long protrudable chelicerae Claws on tarsus Dorsal and ventral plates
Metastigmatid- types of ticks
Agasidae= soft ticks Ixodidae= hard ticks
In general about soft ticks
No visible mouthpart from above (except larvae) No shield Feed for short times freq (not larvae) 2-8 nymphal stages Painful bite
2 soft ticks species affecting birds
Argas persicus
Argas???
In general about argas species
Temp Blood-sucking Larvae, nymph and adults feed several times at night Vectors Mostly host-specific May cause anaemia
General morph of soft tick species
Yellow/brown grey Mammilated, leathery soft cuticle- looks like 'backpack' that is full when fed! Capitulum in ventral side No sexual dimorphism Circular body
In general about hard ticks
Visible mouthpart from above Dorsal shield Larva, nymph and adults feed slowly and ONCE ONE nymphal stage Painless bite Temporary Obligate blood-sucking Not strictly host specific
General morph of hard ticks
Only in males does the shield cover the entire body When not fed- same size as poppy seeds Colour varies Short and wide palps Shield on back Plates on ventral side Capitulum visible dorsally Body margin becomes rounded when engorged (not the case for males) Strong sexual dimorphism Haller's organs on legs
What is the life-cycle of I.ricinus
3-8 years
Whatare the 2 basic types of Ixodidae
Nidicolous= endophillic: ‘stays in nest’ e.g hexagonous (hedgehog tick)
Non-nidicolous=exophilic: ‘leaves the nest’ e.g ricinus (sheep tick)
Hunting ticks
Dermacentor reticularis Hyalomma marginatum Have eyes Adult= exophillic Larvae and nymphs= endophillic
Main general of Ixodid ticks
Ixodes spp
Haemaphysalis spp
Dermacentor spp.
Rhipicephalus (+boophilus)
Ixodes spp
Dark plain scutum
No eyes
Haemaphysalis spp
Lighter, plain scutum
No eyes
Dermacentor spp
Scutum is ornamneted
Have eyes
Rhipicephalus spp
Brown scutum
Have eyes
Brown dog tick: hepatozoon canis and babesia gibsoni
