Mites Flashcards
Mites belong to the class ………….. and the subclass …………..
Arachnida and subclass acari
What is acarariasis?
A mite infestation and severe infestation is called mange
How many eggs will a female lay?
Only 10-15 but the life cycle is only 1-4 weeks so proliferate rapidly
What are the direct effects of mites?
Direct epidermal damage – skin erythema, pruritus, scale formation, lichenification and crust formation.
The production of cutaneous hypersensitivity
Loss of blood or other fluids
What are the indirect effects of mites?
Mechanical or biological transmission of pathogens.
What are the important genus’ of burrowing mite
Sarcoptes Trixacarus Notoedres Knemidocoptes Demodex
Name the important genus’ of surface mite
Psoroptidae family:
o Psoroptes
o Chorioptes
o Otodectes
Cheyletiella
Trombicula
Dermanyssus
Macronyssidae family:
o Ornithonyssus
Listrophoridae family:
o Chirodiscoides
o Listrophorus
Name the host adapted Psoroptes species
Sheep and cattle (P. ovis)
Horses (P. equi)
Rabbits (P. cuniculi)
What is the cause of sheep scab?
Psoroptes
Severe, hypersensitivity and self trauma
Economically very important
Was a notifiable disease
What is the most common cause of mange in horses and cattle?
Chorioptes bovis Especially in the winter Causes localised infections Often lower legs of horses Often tail and perineum of cattle
What is the most common ear mite of cats and dogs?
Otodectes cynotis
Clinical signs include head shaking, continual ear scratching, and ear droop, pruritus is variable. Causes a characteristic black crusty wax in ears.
What are the main species of Cheyletiella?
C yasurgi (dogs) C blakei (cats) C parasitivorax (rabbits)
Cause the walking dandruff appearance
What are chigger or harvest mites?
Trombicula spp.
Free living and only larvae are parasitic
Larve are bright red- orange, 0.2mm
Hypersensitivity to bites causes pruritis, erythema, scratching
What genus are chicken red mites?
Dermanyssus
(legs on one side)
Mites live off the bird and take a blood mean at night, can bite humans.
Causes loss of condition, drop in egg production and in severe infestations death due to anaemia.
Which genus causes grey black on feathers?
Ornithonyssus
Matting and scabbing, especially around the vent
Blood feeder, primarily remains on the host for its entire life cycle. But…these mites can live off the host bird for 2 to 3 weeks.
What is the most important species of the sarcoptes genus?
Sarcoptes scabei
The entire life cycle (17-21 days) is spent on the host.
Intense pruritus probably due to hypersensitivity to mite faecal material.
Diagnosis by deep skin scraping in 12 or more affected sites.
What species of mite is common on guinea pigs?
Trixacarus caviae
Burrows into the skin and may produce intense pruritus, alopecia, and dermatitis.
What mite is found specially around the head and ears of cats?
Notoedres cati
Which mite causes scaly face and tassel foot in birds?
Knemidocoptes
Found in all types of domestic and wild birds
Highly contagious
Inflammation and exudate that dries forming hyperkeratosis, lameness, deformities, pruritis, scratching
Is demodex a commensal?
Yes in low numbers they live head down in hair follicles and sebaceous glands.
What can cause an opportunistic demodex infestation, is demodex infective?
Often secondary to staphylococcal pyoderma
No as its a commensal.
What can we use to treat mange?
Avermectins Lime sulphur (very good for demodex) Clipping fur and keratolytic shampoos to remove crust and scale Permethrins, amitraz etc for ear mites Steroids for demodicosis and pruritus
How can we treat the environment (very important for birds) for mange?
Organophosphates
Lime sulphur
How many pairs of legs does the female otodectes mite have?
4 pairs but the larvae have 3
