Parasitology: Other Insects and Acarines Flashcards
How many body parts do ticks and mites have?
2
What are the body parts of ticks and mites?
- Idiosoma (body)
- gnathosoma (mouth)
Ticks and mites have what kind of metamorphosis.
incomplete, the larvae appear similar to the adult
How do you determine between a parasitic mite and a non-parasitic mite?
identify structures on the mite that appear to be adaptations for being on animals (suckers, claws, plungers, etc.)
How does knowing what types of mite you will see on an animal determine if an infestation is present?
you can determine if the parasite is truly an infestation or if its just something the animal ate
What is mange?
a skin disease of domestic animals cause by a number of genera of mites
Is there a characteristic skin lesion associated with mange?
no
Can mange lead to pyorderma?
yes
What is Scabies?
a type of mange that refers to an infestation of Sarcoptes spp., but is sometimes used more generally
What is the typical life cycle of a mite?
- all stages on host (poor survival off of host)
- short life cycle (a few weeks)
T/F: Mites tend to be host-specific
True (there are some exceptions)
How are mites transmitted?
direct contact or fomites
How does one diagnose a mite infestation?
skin scraping at periphery of lesion
T/F: an animal can be infested with mites, yet not show any clinical signs
true
What are examples of typical mites:
- Sarcoptes
- Knemidocoptes
- Demodex
- Otodectes
- Chrioptes
- Psoroptes
What are some examples of atypical mites?
- Trombiculids (chiggers)
- Dermanyssus
- Ornithonyssus
What are some examples of subsurface mites
- Sarcoptes
- Knemidocoptes
- Demodex
What are some examples of surface mites?
- Otodectes
- Chrioptes
- Psoroptes
- Trombiculids
- Dermanyssus
- Ornithonyssus
Is Sarcoptes a subsurface or a surface mite?
subsurface
Physical appearance of Sarcoptes scabiei.
- typical parasitic mite
- round body
last 2 pairs of legs are short
Where do female Sarcoptes lay eggs?
in tunnels they burrowed into the epidermis
How long is the general life cycle of Sarcoptes Scabiei?
about 3 weeks
T/F: Sarcoptes Scabiei can infest humans.
False, they can cause lesions, but they can’t infest you
Are there any cross-infections of Sarcoptes between species
no
What are some hosts of Sarcoptes
- common hosts: dogs and pigs
- uncommon hosts: horses and cattle
Clinical importance of Sarcoptes scabiei in dogs.
- can cause intense pruritis, which can lead to self-inflicted trauma, and potentially a secondary bacterial infection
What are some signs of chronic sarcoptic infestation?
- alopecia, thickened, wrinkled skin
- secondary bacterial infection
- self inflicted trauma
where do mites prefer to attempt to feed?
- hairless or thin-haired area
(you might see lesions first appear on face, ears, legs
How does one diagnose Sarcoptes in dogs?
- skin scrapings (several locations)
- fecal exams (may find mites or eggs)
If there are multiple animals within the household, which do you treat for Sarcoptes?
all animals
Do you need to treat the environment when treating for Sarcoptes
nope, just wash the bedding, clean the kennel
Can your dog’s Sarcoptes infestation affect your cat?
yes, in that you may see transient lesion.
no, it will not infest your cat
T/F: there is a Sarcoptic mite of cat with a different genus.
true
What other animals can you see sarcoptic mites on?
- guinea pigs, foxes
What animals do Knemidocoptes affect?
poultry and pet birds
What is a more common name for Knemidocoptes?
scaly leg mite
scaly face mite
(depends on where the lesion is)
Where do you most commonly see Knemidocoptes infestations?
mostly on nonfeathered portions of the body
What is a characteristic lesion appearance for Knemidocoptes infestations?
a honeycomb appearance
Describe general Demodex spp characteristics
- typical subsurface mite
- usually parasitize hair follicles or sebaceous glands
- elongated in appearance, legs on anterior end
Is Demodex host species-specific?
yes
T/F: Some animals have more than 1 Demodex species
True
T/F: Common species of demodex can be though of as normal skin fauna
true, transmission occurs shortly after birth from dam
Which species of host is Demodex most important in?
dogs
When do clinical sign of Demodex infestation appear?
when mites proliferate beyond normal levels. The balance between host and mite shifts to favor the mite
How does a Demodex infestation affect the host’s body?
- interferes with follicle, gland function
- can lead to inflammation, secondary infection
What are the 2 forms Demodecosis appears in with dogs?
- Localized form
- generalized form
What is the localized form of Demodecosis in dogs?
- the immune response is still developing
- affects puppies 3-10 mo. of age
- can see small, hairless regions
- does not cause itching
about how many cases of localized Demodecosis resolve spontaneously?
90%
What is the generalized form of Demodecosis in dogs?
- occurs due to specific immune deficiency
- can be caused by either a progressive spread from localized form in pups OR by adult onset
- more often seen in purebred shorthaired dogs
How do you diagnose Demodex?
- skin scrapings
Where would you find eggs and mites of Demodex?
feces
What are the general characteristics of surface mites?
more ovular than Sarcoptic mites, have longer legs
What is the minimum length of the surface mite life cycle
2 weeks
What are some examples of surface mites?
- Otodectes
- Chorioptes
Psoroptes
What is the worldwide parasite of ear canals in dogs, cats, and ferrets
Otodectres cynotis
In which species do you most often see Otodectes cynotis
cats
What is a major clinical sign of an Otodectes infestation?
intensely pruritic otitis externa
- The exudate looks like coffe grounds in ear
How do you diagnose Otodectes
ear swab and microscopic Identification
how do you treat Otodectes cynotis
clean the ear and use a miticide
What is the most often encountered large animal mite in the US?
Chrioptes spp
Which animals are affected by Chorioptes spp.?
Which animal is the most frequently affected?
- ruminants, horses (spp. are host-specific)
- cattle
Predilection site of Chorioptes in cattle
- tailhead (common)
- udder
- perineal region
Predilection site of Chorioptes in small ruminants
- leg
- lower body
Predilection site of Chorioptes in Horses
- legs, esp. Feathered horses
What do Psoroptes ovis and bovis cause in their hosts?
- severe pruritis and skin lesions
how do you diagnose a Psoroptes infestation?
skin scrapings
Is a Psoroptes infestation reportable?
yes
Are Trombiculids host-specific?
no
Which stage of the trombiculid lifecycle is parastic?
larvae
Where would one get a trombiculid infestation?
the environment
What is the issue with a trombiculid infestation?
the pruritis persists after the mite has gone, so you might end up treating the symptom, not the cause
What group do chiggers and harvest mites fall into?
Trombiculids
How are Trombiculid infestations diagnosed?
visual confirmation of red or orange mites, especially on face, ears in dogs and cats
Treatment of Trombiculid infestations
acaricidal treatments if mites are present
What is the importance of Mesostigmatid mites
They’re the bird mites
Are mesostigmatid mites larger or smaller than most parasitic mites
larger
What is the scientific name of the northern fowl mite?
Ornithonyssus sylviarum
what are some clinical signs associated with O. sylviarum infestation?
- decreased weight gain
- egg production issues
Where does O. sylviarum life stages typically occur
all life stages on host
How does Dermanyssus differ from O. sylviarum parasitically
Dermanyssus only visits host to feed, can be zoonotic
O. sylviarum stays on host
