mites Flashcards
describe the typical mite lifecycle
- adult females lay only 10-15 eggs
- eggs hatch into larvae
- larvae mature into nymphs
- whole life cycle takes only 1-4 weeks
what is acariasis
mite infestation
what is severe acariasis refered to
mange
what are the direct and indirect effects of mites
direct:
- skin erythema
- pruritus
- scale formation
- lichenification
- crust formation
- production of cutaneous hypersensitivity
- loss of blood or other fluids
indirect:
- mechanical or biological transmission of pathogens
list burrowing mites
- sarcoptes
- trixacarus
- notoedres
- knemidocoptes
- demodex
list surface mites
- psoroptes
- chorioptes
- otodectes
- cheyletiella
- trombicula
- dermanyssus
- orinthonyssus
- chirodiscoides
- listrophorus
what animals are important in psoroptes infestations
sheep and rabbits
- sheep scab caused by psoroptes
- very irritant causing rubbing and trauma
surface mite
what species are affected by chrorioptes bovis
cattle and horses
- in horses see crusting lesions above foot
- in cattle crusts in neck, tail and perianal regions
- causes loss of production due to iritation and rubbing (rarely causes trauma)
surface mite
why species do you find otodectes cynotis in and where/what lesions look like/clinical sings/how do you diagnose
- ear mites of cats and dogs (and other carnivores)
- causes severe iritation and red crusts in the external ears
- if left untreated, infection can spread from outer to inner ear with possible secondary bacterial or fungal infections
- clinical signs include head shaking, continual ear scratching and ear droop, pruritus variable
- diagnose by visualising with otoscope or taking swab of characteristic black crusty wax
surface mite
what are cheyletiella
- largly free living, often predatory mites
- 3 parasitic species: yasurgi (dogs), blakei (cats) and parasitivorax (rabbits)
- cause scaling dermatitis and pruritus
- usually quite mild but can be severe especially if animal already ill
- mites walking amongst debris give rise to “walking dandruff”
surface mite
what is trombicula
- chiggers or harvest mites
- free living, only larvae are parasitic
- larvae are bright red/orange and 0.2mm
- ground living so often found on legs, bellies or face/head or grazers
- hypersensitivites
surface mite
what is dermanyssus
- a major parasite of domestic fowls but also occurs on other birds
- dermanyssus mites live off the bird in dark places but take a blood meal at night (can and do bite humans)
- causes loss of condition, drop in egg production and in sever infestations death due to anemia
surface mite
what is ornithonyssus
norther fowl mite
- blood feeder, primarily remains on the host for its entire life cycle
- can live off the host bird fo 2-3 weeks
- grey-black on feathers
- matting and scabbing especially around vent
- reduced production, anemia and occassionaly death
- may spread infections
surface mite
what is sarcoptes scabei
- one species with host adapted strains, found on mammals and can jump species (zoonotic)
- highly contagious (only via direct contact)
- the entire lifecycle (17-21 days) is spent on the host
- intense pruritus probably due to hypersensitivity to mite fecal material
- diagnosed by deep skin scraping in 12 or more affected areas
burrowing mite
what is trixacarus caviae
- common in guinea pigs
- burrows into the skin, may produce intense pruritus, alopecia and dermatitis
- severely infested animals may show signs of secondary bacterial infection and stress
- diagnosis is made by examining hair shafts or skin scrapings and indentifying the mite
burrowing mite
