4- Diagnostic approach to common ectoparasites seen in practice Flashcards
How do you diagnose fleas?
Physical exam
Coat brushing/comb
Wet paper test
How do you diagnose lice
Coat brushing/ comb
unstained acetate tape strip
When sampling which lesion should you sample?
Primary lesion if possible
How do you diagnose surface mites
coat brushings/ combings
ear wax into liquid paraffin on slide
superficial skin scraping into LP
unstained acetate tape strip
Microscopy generally required
How do you diagnose deep mites
Deep skin scraping into LP
demodex= hair pluck
microscopy always required
How many legs do ticks have?
8 legs
T/F Lice are dorsoventrally flattened
True
What insect is laterally flattened
Fleas
Name the 2 types of lice & how you distinguish between them
Chewing - head wider than thorax
Sucking - Head narrower than thorax
Name the 2 types of mites
Surface
Burrowing
What is the mite that is cigar-shaped?
Demodex
T/F Lice are species specific
True
What is psoroptes?
Surface mite
Do you need to use microscopy when diagnosing lice
they are visible with naked eye
microscopy needed to assess if chewing/sucking louse +/- to speciate
Which ectoparasites are found above skin surface
fleas
lice
surface mites
Describe how Psoroptes antibody serology works
detects host antibodies to recombinant mite antigen
can detect sheep scab infestation within 2 weeks of contact
potential for false positives from previous resolved infection
How many samples should you take when investigating ectoparasites
minimum x6 skin scrapings
When looking at mites with microscopy what settings to use
View on x4-10 with condenser diaphragm partially closed (+/- lower condenser) –> reduce light –> increase contrast of parasites
Describe how to perform a deep skin scraping
Clip hair very short
Squeeze skin – constantly/ intermittently
Scrape until capillary bleeding seen
Describe how you would test for psoroptes
take superficial scrapes at leading edge of lesion
What is psoroptes
sheep scab
is a surface mite
What species does Felicola sp affect
is a chewing louse
cat
What species does Damalinia (Bovicola) spp affect
Horse, cattle, sheep, goats
is a chewing louse
What species does Trichodectes sp affect
dog
is a chewing louse
