Diagnostic approach to common ectoparasites seen in practice Flashcards
What is the best method to get a flea sample?
Coat brushing/comb +/- wet paper test – no need for microscopy
What is the best method to get a lice sample?
Coat brushing/comb, unstained acetate tape strip, trichograms (egg on hair).
Visible with naked eye, but microscopy needed to assess if chewing/sucking louse +/- to speciate
What is the best method to get a surface mite sample?
Coat brushings/combings or ear wax into liquid paraffin (LP) on slide; superficial skin scrape into LP; unstained acetate tape strip.
Trichogram (egg on hair) for Cheyletiella.
Microscopy generally required.
What are the best methods for getting a deeper mite sample?
microscopy always required
Deeper skin scrapings into LP:
Sarcoptes – scrape into epidermis
Demodex – deeper - scrape until blood oozes. Also adjunctive tests: hair pluck + ?acetate tape impression smears of squeezed skin
In what situations is serology used to identify parasites?
Psoroptes antibody serology - sheep scab
Sarcopted IgG serology - canine
Flea IgE serology
Describe the best practice for sampling/microscopy of parasites?
Primary lesion
Multiple samples
Scrape until capillary bleeding seen
View area systematically
x4-10
Condenser diaphragm partially closed
Look in house (mites are short lived)
Where is the best place to find parasites on a sheep scab?
superficial scraps at the leading edge of the lesion
How can skin scraps be used to monitor treatment for demodicosis?
Repeated monthly - treat until 2 consecutive sets of -ve scrapes
scrape same sites and record number of each life stage and % live vs dead
How can insects and arachnids be differentiated?
How can flies, fleas and lice be differentiated?
How can chewing/biting and sucking lice be differentiated?
How can ticks and mites be differentiated?
tick - 2-20mm
Mites - <1mm
How can hard ticks be differentiated? - ixodes, rhipicephalus, dermacentor
How can surface and burrowing mites be differentiated?
How can burrowing mites be differentiated?
How can psoroptes/chorioptes be distinguished from other surface mites?
What is the host species of damalinia (chewing lice)?
horse
cattle
sheep
goats
What is the host species felicola (chewing lice)
cats
What is the host species of trichodectes (chewing lice)
dogs
What is the host species of Lipeurus, Cuclotogaster, Menacanthus (chewing lice)`
birds
What is the host species of Gliricola sp, Gyropus sp (chewing lice)
guinea pig
what is the host species haematopinus (sucking lice)
cattle
pigs
horses
What is the host species of linognthus (sucking lice)
cattle
sheep
goats
dogs
What is the host species of psorptoes and chorioptes (surface mite)
cattle
SHEEP
horses
camelids
rabbits
