Exam II - Order Acari - Mites Flashcards
Describe the different strategies utilized by Order Acari
- Burrow into the host epidermis (Sarcoptes)
- Non-burrowing, entirely on skin surface (Cheyletiella, Chorioptes)
- Restricted to an area of the body (Otodectes)
What is the common name for Sarcoptes scabiei?
Sarcoptic mane mite, itch mite, scabies mite
What is the scientific name for the Sarcoptic Mange Mite?
Sarcoptes scabiei
What is/are the host(s) for Sarcoptes scabiei?
All domestic animals and humans.
It is rare in cats
Describe the appearance of the Sarcoptes scabiei adult
round, 500 um diameter, short legs, suckers on long unsegmented stalks differ between sexes
How many weeks can Sarcoptes scabiei live on the surface of the skin?
Trick question! Sarcoptes scabiei is a burrowing mite. It can NOT live on the surface of the skin.
What is the PPP for Sarcoptes scabiei?
2-3 weeks
Describe the life cycle of Sarcoptes scabiei
Fertilized female tunnels in upper layers of epidermis, feeding on damaged tissue. Eggs are laid in tunnels & hatch in 3-5 days to larvae that crawil on skin surface.
Larvae burrow and form molting pockets where nymphs and adults develop.
All stages tunnel in the epidermis, resurface, and burrow again. Adult male emerges and seeks female. After fertilization, the process starts over.
Where do Sarcoptes scabiei nymphs and adults develop?
**molting pockets **in the host’s skin
What is/are the site(s) of infection for Sarcoptes scabiei?
Skin.
Describe any pathogenesis associated with Sarcoptes scabiei
Erythema, scale and crust formation
Describe some clinical signs associated with Sarcoptes scabiei
Begins on hairless areas of body (lateral elbow & pinna of the ear are common starting places)
Lesions of follicular papules, erythema, crusts of dried serum and blood, and pruritus
How would you diagnose Sarcoptes scabiei?
Skin scraping, but recovery of the mite is difficult
Describe treatment and prevention options for Sarcoptes scabiei
MCLs are effective, treatment of pets cure the humans they infest.
This is very contagious, so treat all of the animals in the household
What is the common name for Demodex canis?
Demodectic mange mite, follicle mite
What is/are the host(s) for Demodex canis?
Dogs.
Describe the appearance of the Demodex canis adult
Cigar with Legs
Adults have elongate tapering body, 400 um, 4 pairs of stumpy leggs on anterior
Describe the life cycle of Demodex canis
Entirely in hair follicles and sebaceous glands. Mites are normal fauna of skin. Adults in follicles lay eggs, larvae and nymphs at mouth of follicle. Egg to adult in 2-4 weeks.
Transmission to newborn pups is from bitch to pup by direct contact during nursing in first 2-3 days postpartum
What is/are the site(s) of infection for Demodex canis?
Hair follicles and sebaceous glands
Describe any pathogenesis associated with Demodex canis
The presence of small numbers of mites is normal.
In larger numbers of mites, we may see localized demodicosis associated with alopecia, erythema and no pruritis.
Prognosis for recovery is excellent
What is the first clinical sign you will notice in localized demodicosis?
alopecia
How would you diagnose Demodex canis?
Skin scrapings can revel the mite, BUT presence does not necessarily indicate disease since these are normal inhabitants of the dog
Describe generalized demodicosis
characterized by 5 more more areas of localized disease or entire body region, hair sparse and skin coarse and dry, develops to “red mange”.
Concomitant staphylococcal pyoderma develops, pustules develop, open, and ooze. Very difficult to cure
Describe treatment & prevention options for generalized demodicosis
Amitraz (formamidine) is approved
What is the common name for Cheyletiella yasguri?
Walking dandruff
Who is/are the host(s) for Cheyletiella yasguri?
dogs, humans
Describe the appearance of the Cheyletiella yasguri adult
Body has a “waist”, legs long, 500 um. Called “walking dandruff because large enough to be seen walking against a dark background, prominent palpal claws
What is/are the site(s) of infection for Cheyletiella yasguri?
Fur and hair
Describe the life cycle of Cheyletiella yasguri
Mites live on skin, hair and tunnel in epidermis debris. Mites feed on debris. Eggs attached to hair. Transmission is by direct contact. Life cycle is completed in 2 weeks.
How would you diagnose Cheyletiella yasguri?
dandruff. Exam of an adhesive tape swap may reveal mites also
What are the treatment options for Cheyletiella yasguri?
insecticides
What is the scientific name for “walking dandruff”
Cheyletiella yasguri
What is the common name for Otodectes cynotis?
ear mite
What is/are the host(s) for Otodectes cynotis?
Dogs, cats, ferrets, & foxes
Describe the appearance of the Otodectes cynotis adult
500 um in length. Long legs extending beyond body margin, suckers of males and females differ, copious dark cerumen is observed.
Here are two now… having sex:
What is/are the site(s) of infection for Otodectes cynotis?
Ears.
Describe any pathogenesis associated with Otodectes cynotis
In cats: dry, waxy parchment-like material in ears with large numbers of mites. Can lead to secondary infections resulting in external ear inflammation (otitis externa)
What clinical sign should you look for with Otodectes cynotis
frequent shaking of head
How would you diagnose Otodectes cynotis?
Behavior of the animal, exudate in ear canal, mites on slide
What are some treatment options for Otodectes cynotis?
Ivermectin otic suspensions, revolution, and other compounds are approved
