Mites Flashcards
• How many body segments & pairs of legs do Acari have?
Two body segments (gnathosoma & idiosoma) & 4 pairs of legs
• How can you differentiate the larval stage from other stages?
Larval stage has 6 legs, not the usual 8
• What do parasitic mites feed on?
Blood, lymph, skin debris or sebaceous secretions
• Describe the life cycle of a mite
Egg -> larvae -> nymph -> nymph -> nymph -> adult
• List the common burrowing mites
Sarcoptes, Trixacarus, Knemidocoptes, Demodex
• How would you diagnose Sarcoptes?
By deep skin scraping in 12 or more affected sites
• What is Trixacarus caviae?
A sarcoptid common in guinea pigs
• What mite causes a condition commonly known as scaly face, scaly foot or tassel foot in birds?
Knemidocoptes
• What are the two types of demodicosis caused by Demodex?
Localised demodicosis – commonly on the face, and forelegs in young animals
Generalised demodicosis – more severe, widespread from onset, usually underlying disease
• List the common surface mites
Pscoptes, Chorioptes, Otodectes, Cheyletiella, Trombicula, Dermanyssus, Ornithonyssus, Chirodiscoides, Listrophorus
• What is a highly diagnostic feature of Psoroptes?
Funnel shaped pulvilli attached to three jointed pretarsi, the jointed pretarsi are highly diagnostic since in most other mites they are un-jointed
• What are the two most common species affected by Psoroptic mange?
Sheep & rabbits
• What species are infected by Chorioptic mange?
Cattle & horses
• What are the clinical signs of an Otodectes infection?
Head shaking, continual ear scratching, ear droop, pruritus is variable
Common cause of otitis externa
• Which mites have a characteristic waist and large palps that look like an extra pair of legs & causes a condition known as walking dandruff?
Cheyletiella
• Which mite is only parasitic during the larval stage?
Trombicula (chiggers or harvest mite)
• What are the guinea pigs and rabbits fur mites?
Guinea pig fur mite – Chirodiscoides caviae
Rabbit fur mite – Listrophorus gibbus
• How is Listrophorus gibbus transmitted?
Direct contact with the host, animal bedding, or hair and debris
• What are the two major mites that affect birds?
Dermanyssus (chicken red mites) & Ornithonyssus (the Northern fowl mite)
• How do these two mites differ?
Dermanyssus live off the bird and take a blood meal at night
Ornithonyssus primarily remain on the host for its entire life cycle
• How do you control a mite infection?
Need to identify the mite to ensure appropriate treatment can be used
• What are the direct and indirect effects of mites?
Direct – direct epidermal damage, the production of cutaneous hypersensitivity, loss of blood or other fluids
Indirect – mechanical or biological transmission of pathogens
