Chapter 6 - Parasites Flashcards
Why do macrocyclic lactones not affect mammals when they potentiate GABA?
They do not cross the blood brain barrier in adults. GABA is limited to the CNS in mammals but is a peripheral neurotransmitter in parasites.
Which species of parasite causes hookworm dermatitis?
Ancylostoma brazilense or caninum
Uncinaria stenocephala
Are Ixodid ticks soft or hard shelled?
Hard
Are Argasid ticks soft or hard shelled?
Soft
Which life cycle stage of Neotrombicula autumnalis feeds on mammals?
Larvae
Vacuum or flea-combing is diagnostic for Cheyletiella in what % of dogs?
85%
Vacuum or flea-combing is diagnostic for Cheyletiella in what % of cats?
42%
How long do adult female Cheyletiella mites survive off host?
Up to 10 days
With immunocompetance theories associated with demodicosis, what happens to Th1 and Th2 responses?
Th1 decreases and Th2 increases
What is the most common anatomical site for localised demodicosis?
Face (periocular) and commissures of the mouth
Which breed is predisposed to a nodular form of generalised demodicosis?
English Bulldog
Which Demodex mite causes a seborrheic presentation and which breeds are predisposed?
Injai; Terriers (WHWT and Shih Tzu)
When should you consider skin biopsy to diagnose demodicosis?
In fibrotic lesions and Shar-Peis
How often should skin scrapes be performed when treating generalised demodicosis?
Every 2-4 weeks
With generalised demodicosis, is clinical or parasitological cure first apparent?
Clinical cure
How long is Amitraz retained in the skin for after application?
Two weeks
When do most relapses of generalised demodicosis occur?
Within the first 3 months of stopping treatment
Generalised demodicosis may be more common in which breeds of cat?
Siamese and Burmese
Which part of the skin do Demodex gatoi inhabit?
Stratum corneum
Trunk and ventral abdomen in particular
What size are adult Sarcoptes scabiei mites?
200-400 um
The face and pinnae are involved in what % of dogs with sarcoptic mange?
70%
What are the signs of Sarcoptes scabiei infestation in cats?
Pruritic pinnal and facial crusted papular dermatitis; crusted pododermatitis; generalised crust and/or scale and pruritus; self-induced hair loss
How long does seroconversion take after innoculation with Sarcoptes scabiei?
Up to five weeks
With sarcoptic mange, do you need to treat in-contacts and the environment?
Yes, you can get asymptomatic carriers and mites can survive off host for up to 21 days