Parasitology mites Flashcards
Phylum and subclass for mites
P- Arthropoda
Sc- Acari
What are the four main stages in the life cycle of mites?
Egg
Larva
Nymph
Adult
Leg numbers
Nymphs, adults 8
Larvae 6
What are the 2 functional groups of important mites?
Typical parasitic mite
Atypical parasitic mite
General info about typical parasitic mites
Share many traits with lice: usually host specific, all stages on host, usually short life cycle, transmitted by direct contact, fomites, suckers on legs
Doesn’t survive well off the host
Causes “mange”
diagnosis by skin scraping
General info about atypical parasitic mites
may visit host intermittently
may have some nonparasitic stages
Definition of mange
skin disease of domestic animals caused by number of genera of mites
No characteristic lesion, other skin diseases could look similar
Definition of scabies
mange, cause may vary
small animals usually mean Sarcoptes
large animals could mean other mites
General info about sarcoptic mites
typical parasite mites
burrowing mites- females lay eggs in tunnels in epidermis
Life cycle takes about 3 weeks
Easily transmitted between animals
Diagnosis for sarcoptic mites
Skin scraping- scrape periphery
May be difficult to find so scrape many spots (itching may make the host look worse than the number of mites)
May find mites or eggs on fecal exam (from grooming)
Sarcoptes scabiei
Separate varieties for most common domestic mammals- most often dogs, also pigs
Don’t seem to cross infest
Not all sarcoptes are the same spp. but called the same with variant by host
Sarcoptes scabiei, var canis Clinical importance
Mites like hairless areas/thin hair- lesions may appear first on face, ears, legs
Intense pruritis
Chronic sarcoptic mange you see
alopecia, thickened, wrinkled skin
secondary bacterial infection
self inflicted trauma
Treatment/control of canine sarcoptes
Treat all animals in household
Macrolides used primarily
Extensive environmental treatment not needed b/c live on host– wash bedding, clean kennel, etc.
Zoonotic potential of canine sarcoptes
Lesions in area of contact but can’t establish on humans
humans have their own Sarcoptes
Sarcoptes in pigs
Economically important- lost production in young pigs
Old sows act as carriers
Eradicable from closed system with macrolides
Sarcoptes in other livestock
Rare in ruminants, horses
Can cause severe disease in camelids
Large animal treatment is macrolides
Knemidocoptes, general
Sarcoptic mange mite of poultry and pet birds worldwide
Called scaly face or scaly leg mite depending on where lesions usually seen
Can be a very serious disease
Treat with macrolides
Knemidocoptes, life cycle/ details more than just general
Most common species seen on nonfeathered portions of body
Mites burrow in, cause crusty, scaly lesions
Lesions have a honeycomb appearance
May cause malformations of beak, claws
Psoroptic mites, general characteristics
Surface dwellers, not burrowers
Oval, not round with longer legs than sarcoptic mites
Short life cycle- minimum 2 weeks
Diagnosis by skin scrape (except ear mites)
Macrolides effective
Psoroptes ovis, general and zoonosis
Ruminants, host specific strains- found worldwide, eradicated from sheep in US, status unsure in cattle
Transmission by direct contact
Handlers can get temporary lesions
Psoroptes ovis, clinical importance
Cause severe pruritis and skin lesions Diagnosis by skin scraping *NOTIFIABLE INFESTATION* Importance diminishing with highly effective macrolides Treat all animals
Psoroptes cuniculi
Primarily otic parasites of rabbits
Occasionally in alpacas, goats; rare in horses
Chorioptes spp.
Ruminants, horses, but host specific Direct contact transmission Predilection sites: cattle- tailhead, under and perineal region small ruminants- leg, lower body horses- legs, esp. feathered horses
Otodectes cynotis, general
Dogs, cats, ferrets (mostly cats)
Parasite of ear canal, transmission by direct contact
Otodectes cynotis, clinical signs/importance
Otitis externa- can cause intense pruritis
Coffee grounds in the ear
very common mite
Otodectes cynotis, diagnosis and treatment
Ear swab, otoscope
Clean ear, miticide- macrolides, pyrethrins
Treat all animals in environment
Demodex spp., general
Highly host species specific
Normal part of skin flora
Usually parasite of hair follicles or seabaceous glands
Transmission occurs shortly after birth from dam
Demodex, clinical importance
Important in dogs, other hosts rare signs
Clinical signs appear when mites proliferate beyond normal levels
Interfere with follicles, gland function
Can lead to inflammation, secondary infection
Canine demodectosis occurs in 2 main forms
localized form
generalized form
Localized form of demodectosis
Some pups (usually 3-10 m of age)
Small, hairless regions
Nonpruritic
90% resolve spontaneously, 10% progress
Generalized form of demodectosis
Lesions occur and spread
Progressive spread from localized in pups
Also adult onset
More often in purebred short haired dogs
Canine Demodex clinical signs
Generalized disease thought to indicate specific immunodeficiency
alopecia, erythema, seborrhea, pyoderma, pruritis follows continued inflammation and secondary infection
Diagnosis of Demodex in dogs
Deep skin scraping, squeeze skin fold
Look like cigar with legs
Eggs and mites in feces
More mites and juveniles has a lower prognosis
Treatment of Demodex in dogs
Amitraz, macrolides (most common)
Genetic predisposition- don’t breed animals with a history of generalized disease
Demodex in spp. other than dogs
Cat- rare ear, face mange
Ruminants- usually non-pruritic pustules
Humans- rare lesions
