National Veterinary Examination Preventive Veterinary Medicine II: Viral and Parasitic Diseases: practice questions

1 · Foot-and-mouth disease · easy

In an FMD epidemic, which species is described as the 'amplifier' host and why?

1. Pigs: they exhale far more airborne virus
2. Sheep, because they carry the virus silently and spread it through markets
3. Cattle, because they show the most obvious vesicles on the tongue and feet
4. African buffalo, because they carry SAT viruses in the pharynx for years

2 · Foot-and-mouth disease · medium

A 3-week-old calf on a farm with an FMD outbreak dies suddenly without vesicles. What lesion would you expect at necropsy?

1. Raised button ulcers scattered over the caecal and colonic mucosa
2. Grey-white 'tiger heart' streaks in the myocardium
3. Zebra striping along the folds of the rectum
4. Haemorrhage at the base of the pulmonary artery

3 · Foot-and-mouth disease · easy

In pigs, vesicles on the snout and feet cannot be attributed to FMD on clinical grounds. Which disease produces identical lesions?

1. Classical swine fever
2. Porcine circovirus type 2
3. Swine erysipelas (diamond skin)
4. Swine vesicular disease

4 · Peste des petits ruminants · medium

A flock of goats bought at a market develops fever, matted eyelids, foul-smelling erosions on the gums, profuse diarrhoea and coughing; several die. Which disease is most likely?

1. Contagious caprine pleuropneumonia
2. Haemonchosis with bottle jaw
3. Contagious ecthyma (orf)
4. Peste des petits ruminants

5 · Bluetongue · easy

Which sample and test are most appropriate to detect current bluetongue infection in a febrile ewe?

1. Serum for a single competitive ELISA
2. Whole blood in EDTA for RT-PCR
3. Skin scraping for direct microscopy
4. Faeces for a sedimentation test

6 · Rabies · medium

An apparently healthy, vaccinated pet dog bites a child. What is the standard veterinary action in many countries?

1. Collect saliva for a serum antibody test and release the dog
2. Confine and observe the dog for 10 days, testing it if signs appear
3. Euthanase the dog at once and send the whole body for histology
4. Revaccinate the dog and release it to the owner the same day

7 · Canine distemper, canine parvovirus and infectious canine hepatitis · hard

Why does WSAVA recommend that the final puppy core vaccine dose be given at 16 weeks of age or older?

1. Maternal antibody can block vaccine responses until about 16 weeks in some puppies
2. Earlier doses cause distemper in most puppies through vaccine reversion
3. The puppy immune system cannot respond to any vaccine before 16 weeks
4. Parvovirus infection does not usually occur before 16 weeks, so earlier doses waste vaccine

8 · Viral diseases of horses · medium

On a yard, a mare aborts in late gestation and a week later a gelding develops hindlimb ataxia and dribbles urine. Which virus is most likely?

1. Equine herpesvirus 1
2. Equine infectious anaemia virus
3. Equine herpesvirus 4
4. Equine influenza virus

9 · Trypanosomosis · medium

Several thin blood smears from a camel suspected of surra are negative. Which test improves sensitivity for detecting trypanosomes in blood?

1. Repeating the thin smear stained with Ziehl-Neelsen
2. Microhaematocrit centrifugation and examination of the buffy coat
3. Faecal flotation in saturated sodium chloride
4. Rose Bengal plate test on a single serum sample collected from the camel

10 · Helminthoses · medium

In the FAMACHA system for small ruminants, which animals are normally drenched?

1. Every animal in the flock at each check, whatever its individual score
2. Those with pale to white conjunctivae, scoring 4 or 5
3. Those with red conjunctivae, scoring 1 or 2
4. Only animals with diarrhoea, whatever the score