National Veterinary Examination Clinical, Diagnostic & Immuno-Parasitology: practice questions

1 · Sedimentation and flotation techniques · easy

Which flotation solution is preferred for detecting Giardia cysts in dog faeces?

1. Sheather's sugar at SG 1.27, with passive flotation
2. Zinc sulphate at SG 1.18, with centrifugation
3. Tap water sedimentation stained with methylene blue
4. Saturated sodium chloride, read after one hour

2 · Skin scrapings · easy

For suspected sarcoptic mange in a dog, a skin scraping should be:

1. Taken from the centre of old, thickly crusted lesions only
2. Superficial, from a single site in the lumbar area only
3. Deep, multiple sites, to capillary ooze
4. Taken with a dry blade and stained before examination

3 · Skin scrapings · easy

Dark specks combed from a cat's coat dissolve into a red-brown halo on damp white paper. This confirms:

1. Fungal spores from a dermatophyte infection
2. Flea faeces
3. Ear mite debris shed from the ear canal
4. Lice eggs attached to the hair shaft

4 · Serodiagnosis of parasitic infections · medium

Why is a positive Toxoplasma antibody test in a healthy adult cat reassuring to a pregnant owner, rather than alarming?

1. Seropositive cats usually shed oocysts all their lives but these oocysts are harmless to people
2. Cats usually shed oocysts briefly after first infection, before or around seroconversion
3. Toxoplasma antibodies in cats mean the parasite is the canine species, not T. gondii
4. Antibody shows the cat has been vaccinated, and vaccinated cats never carry tissue cysts

5 · Anti-parasitic vaccines · medium

The EG95 recombinant vaccine is given to sheep to:

1. Prevent hydatid cyst development from Echinococcus granulosus eggs
2. Prevent dogs from carrying adult Echinococcus tapeworms
3. Prevent sheep from shedding Moniezia eggs onto pasture
4. Prevent Taenia multiceps cysts forming in the sheep brain

6 · Anti-parasitic vaccines · medium

Live coccidiosis vaccines for chickens depend for full protection on:

1. A single injectable dose given at the start of lay only
2. Including an anticoccidial drug in feed at full dose all the time
3. Keeping chicks on wire floors to avoid any oocyst contact
4. Recycling of vaccine oocysts in the litter during the first weeks

7 · Anti-parasitic vaccines · medium

Live attenuated Babesia vaccines for cattle are best given to young animals because:

1. Young cattle have no ticks to compete with the vaccine strain
2. Young cattle have inverse age resistance and react less severely
3. Adult cattle cannot make any antibodies against Babesia
4. The vaccine is killed by antibodies in adult rumen fluid

8 · Integrated parasite control · medium

In adult horses, current guidance favours which approach to strongyle control?

1. Treat based on egg counts, leaving low shedders untreated
2. Stop all treatment once a single negative count is obtained
3. Rotate drug classes at each treatment, regardless of counts
4. Treat every horse with the same drug every six weeks

9 · Integrated parasite control · medium

A FECRT on a sheep farm shows apparent failure of a drug. Before concluding resistance, what is the most important thing to check?

1. That treated and control sheep grazed different paddocks for months
2. That every animal was dosed for the heaviest weight with a calibrated gun
3. That the faeces were frozen promptly at −20 °C to keep eggs from hatching
4. That only lambs with zero pre-treatment egg counts were included