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99 Cards in this Set

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Four sub-orders of Acarina
1. Ixodoidea

2. Mesostigmata

3. Prostigmata

4. Astigmata

Mites vs ticks
Resemble ticks but smaller

Do not have a hypostome with rows of teeth

Abundant, most free living

Respiratory openings
Body divisions
Capitulum with palps and chelicerae, and idiosoma
Life cycle of mites
Egg, larva, nymphs (proto-, dueto-, trito-), adults
What kind of parasites are mites?
Can be intermittent parasites in nests or burrows, or permanent parasites
Where can mites be found on a host?
On skin, in ears or respiratory system
Effect of mites on host
Blood loss


Hair loss

Scab formation

Vectors of viruses and protozoans

Which of the four sub-orders of Acarina refer to mites?
Mesostigmata (Gamasid mites)

Prostigmata (Trombidiform mites)

Astigmata (Mange mites)


Stigmata between coxaeLegs at anterior end of body

Gamasid mites

Legs at anterior end of body

Many free-living

Stigmata on capitulum, anterior to coxaeFeather-like setae

Stigmata on capitulum at base of chelicerae

Chelicerae adapted for piercing

Feather-like setae

Stigmata absentFront pairs of legs separated from back pairs
Stigmata absent

Front pairs of legs separated from back pairs

Main genera of Mesostigmata


Dermanyssus gallinae
Dermanyssus gallinae
Red mite of poultry

Very common

Triangular anal plate

Nocturnal blood feeders

Spend most of life in environment

Hosts of Dermanyssus gallinae
Birds & mammals
Life cycle of Dermanyssus gallinae
Eggs, larva, 2 nymphs

Eggs laid in crevices

Life cycle 7 days

Pathogenesis of Dermanyssus gallinae


Transmit Borrelia anserina

Control of Dermanyssus gallinae
Removal of rubbish and all shelter for mites and spraying with 1% malathion
Ornithonyssus spp
Ornithonyssus spp

Fowl mites, referred to as 'starling lice'

Two species: O. bursa, O. sylviarun

Oval anal plate

Feed on birds while in nest

Some on birds all the time

Blood feeders

Not host specific

On which hosts are Ornithonyssus spp common on?
Wild birds

Found in bird nests

Pathogenesis of Ornithonyssus spp.
O. bursa:

Hypersensitivity on man and animals

Can kill newly hatched chickens and adult birds

Commonly puts birds off the lay

O. sylviarum:

Irritation, anaemia, low fertility in roosters

Other mesostigmatid mites
May be uncommon or non-pathogenic

Nasal mite of the dog: Pneumonyssoides caninum

Ear mite of cattle: Raillietia auris

Snake mite: Ophionyssus natricis

Canary lung mite: Sternostoma tracheacolum

Main genera of Prostigmata




Trombicula spp.
Chiggers, harvest mites

Only larvae are parasitic

Attach in clusters

Often yellow or orange

Transmit scrub typhus (Rickettsia australis)

T. sarcina causes black soil itch in Qld

Demodex canis

Features of Demodex canis

Legs very short at front of body

Localisation of Demodex canis
Hair follicles

Feed on cytoplasm

Life cycle of Demodex canis
Egg, 2 nymphs, adults

All stages in hair follicles

Transmission of Demodex canis
Contact during suckling
Demodectic mange
Demodectic mange
All dogs infected, only some develop disease

Short-haired dogs with CMI deficiency

Mainly 6-10 months of age

Predilection sites: eyes, ears, muzzle

Secondary infection with Staph. albus

Infection of follicles leads to hair loss & hyperkeratosis

Disease can be:

- localised or generalised

- squamous or pustular (secondary infection)

Diagnosis and treatment of Demodectic mange

Deep skin scraping



Other species of Demodex
Uncommon or rarely pathogenic

Each host has "own" species


- D. phylloides

- lesions mainly on head


- D. bovis

- damages hide

Sheep, goats, horse:

- D. ovis, D. caprae, D. equi

- rare


- D. folliculorum

- prevalence 50%

- common in blackheads

- base of eyelashes

Psorergates ovis
Psorergates ovis features

The sheep itch mite

Tiny mite

Circular with legs arranged radially

Legs very short

Lives in superficial layers of dermis

Psorergates ovis host
Affects sheep in Australia, Africa, N&S America
Life cycle of Psorergates ovis
Egg, Larva, 3 nymphs, adults

Length: 5 weeks

Transmission of Psorergates ovis
Contact (suckling, shearing)
Predilection sites of Psorergates ovis
Sides, between hip & shoulder near mid-line
Seasonal occurance of Psorergates ovis
Most abundant in winter
Effect of Psorergates ovis on host
Hypersensitivity causes irritation

Rubbing - pulled wool

Not all sheep affected

Spreads slowly in mob

Diagnosis & treatment
Skin scraping

Control can be by OPs, amitraz or ivermectin

None will totally eliminate mite

Ivermectin better in spring when mites are reproducing actively

OPs with amitraz good during quiescent phase

Cheyletiella spp
Cheyletiella genus features
Palpi short and strong

Strong claws on palps

Cheyletiella species
Rabbits: Cheyletiella parasitivorax

Dogs: Cheyletiella yasguri

Cats: Cheyletiella blakei

Effects of Cheyletiella spp on host
Mild mange, often around head

Also bite humans

Two families of Astigmata mites


A = Sarcoptidae

B = Psoroptidae

Sarcoptidae features
Rear legs very short

Burrow in upper layers of skin

Psoroptidae features
Rear legs project

Tissue fluid feeders cause scabs

Sarcoptidae genera




Psoroptidae genera



Sarcoptes scabiei
Features of Sarcoptidae family

Body round

Legs 3 and 4 usually do not project beyond body margin
Features of Sarcoptes scabiei
Triangular scales on dorsum

Wide host range

Strains on specific hosts

Can survive but not reproduce on other hosts

Life cycle of Sarcoptes scabiei
Lives in superficial layers of skin

Lay eggs in tunnel

Larva and 2 nymphal stages

Length: 10-17 days

How long can Sarcoptes scabiei mites survive off host?
Few days
Transmission of Sarcoptes scabiei
Sarcoptes scabiei inside epidermis
Pathogenesis of Sarcoptes scabiei
Burrowing mites cause irritation

Intense pruritis



Lesions begin on face, extend over body

Secondary infection, pustules

Self inflicted trauma


Diagnosis of Sarcoptes scabiei
Skin scrapings

Can be difficult to find mites

Treatment of Sarcoptes scabiei
Most insecticides

Topical only as sarcoptes mites don't feed on blood

Sarcoptes scabiei hosts


Pigs, camels, ferrets, wombats, pigs, humans

Other sarcoptid genera on mammals
Guinea pigs: Trixacarus caviae

Cats & rabbits: Notoedres cati

Rodents: Notoedres muris

Cnemidocoptes spp
Cnemidocoptes species
Cnemidocoptes gallinae

Cnemidocoptes mutans

Cnemidocoptes pili

Cnemidocoptes features

Sarcoptid mites of birds

Legs very short

Found on birds

Where is Cnemidocoptes gallinae found?
In feathers

Depluming mite of poultry

Where is Cnemidocoptes mutans found?
On legs of chickens

"Scaly leg"

Scaly leg

Caused by Cnemidocoptes mutans

Where is Cnemidocoptes pili found?
On beak and legs of psittacines
Cnemidocoptes pili on beak and legs
Features of Psoroptidae family
Body oval

Legs 3 & 4 project beyond body margin

Mites don't burrow, but cause scab formation

Tissue fluid feeders

Genera of Psoroptidae
Otodectes : ear mite of cats and dogs

Psoroptes: mites of rumnants, horses

Chorioptes: mites of ruminants and horses

Differentiating between psoroptes and chorioptes
Psoroptes have jointed pedicels

Chorioptes have simple pedicels

A = Psoroptes (jointed)

B = Chorioptes (simple)

Otodectes cynotis
Otodectes cynotis hosts
Common ear mite of dogs and cats

Also occurs in foxes and rabbits

Pathogenesis of Otodectes cynotis
Causes scabs in external ear canal

Hosts shake heads and rub ears

May get fever and depression in cats

Transmission of Otodectes cynotis
Transmitted by contact, often while suckling
Diagnosis of Otodectes cynotis
With otoscope, unreliable

Examine exudate under microscope

Treatment of Otodectes cynotis
Oral or topical insecticides
Psoroptes species
Sheep scab mite: Psoroptes ovis

Ear mite: Psoroptes cuniculi

Psoroptes equi

Psoroptes natalensis

Psoroptes ovis
Psoroptes ovis features
Large mite

Lives under scabs

Feeds on tissue fluids

Life cycle 9-10 days

High biotic potential

Most abundant in cool weather

Pathogenesis of Psoroptes ovis

"Sheep scab" (but affects cattle too)




Emaciation, high mortality

What areas of the animal does Psoroptes ovis affect?
Starts on shoulders and back, spreads over whole body

In latent cases can occur in ears, inguinal folds, interdigital spaces

How common is Psoroptes ovis?
Common in most countries

Eradicated from Australia

Psoroptes cuniculi
Hosts of Psoroptes cuniculi
Rabbit, horse, goat, alpaca

Common in lab rabbits

Pathogenesis of Psoroptes cuniculi
Causes ear mange

May spread onto face

Causes irritation, shaking of head

Chorioptes bovis

(L to R: male, female)

Chorioptes bovis hosts
Cattle, sheep, goats, horses

Commonly seen in housed sheep and cattle

Pathogenesis of Chorioptes bovis
Chorioptic mange

Often referred to as barn itch

Can cause scrotal mange in rams

Where on the animal does Chorioptes bovis usually occur?
Mainly on legs and belly

Sits underneath scabs