NAVLE (North American Veterinary Licensing Examination) · USA / Canada · International Council for Veterinary Assessment (ICVA); scored by NBME, delivered by Prometric
Original practice questions written to the published syllabus · not past papersBlood and gut protozoa of domestic animals, including trypanosomes, Babesia, Theileria and coccidia, with Anaplasma taught alongside, and their diagnosis and treatment.
In the exams: ICAR AICE-JRF core group 06; ICAR AIEEA-PG 13 (Parasitology)
NAVLE / BCSE (North America)
Clinical cases: anaplasmosis in adult beef cattle, bovine trichomonosis in bulls, cryptosporidiosis and coccidiosis in calves, giardiasis and Tritrichomonas in dogs and cats, toxoplasmosis and zoonotic advice, EPM in horses, Neospora abortion, Leishmania and Babesia in travelled or fighting dogs.
How our questions for NAVLE spread across the units of Veterinary Protozoology. Difficulty: 3 easy, 29 medium, 5 hard.
| Trichomonas | 7 | |
| Toxoplasma | 4 | |
| Cryptosporidium | 4 | |
| Giardia | 4 | |
| Antiprotozoal chemotherapy | 4 | |
| Anaplasma (rickettsial, taught alongside protozoa) | 3 | |
| Histomonas | 3 | |
| Theileria | 2 | |
| Eimeria and coccidiosis | 2 | |
| Diagnosis of protozoal infections | 2 | |
| Trypanosoma and surra | 1 | |
| Babesia | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
A young dog from the southern United States dies suddenly with acute myocarditis; amastigotes are found in cardiac muscle cells. The vector of the likely parasite is a:
D. Triatomine bug
Amastigotes in myocardium in a dog from the Americas indicate Trypanosoma cruzi (Chagas disease), a stercorarian transmitted by triatomine bug faeces. Sand flies carry Leishmania, whose amastigotes are in macrophages rather than heart muscle.
Further reading: Sykes, Greene's Infectious Diseases of the Dog and Cat (5th ed.)
A 500 kg cow with anaplasmosis is to receive long-acting oxytetracycline at 20 mg/kg intramuscularly; the product contains 200 mg/mL. The total volume is:
B. 50 mL
Dose = 500 x 20 = 10,000 mg; 10,000 / 200 = 50 mL. 25 mL corresponds to the 10 mg/kg daily conventional rate; 5 and 100 mL are arithmetic slips. Large volumes are divided between injection sites according to the label — confirm against the product label and your national formulary.
Further reading: Taylor, Coop & Wall, Veterinary Parasitology (4th ed.)
In a dairy herd with endemic Neospora caninum, the route that most maintains infection from one generation to the next is:
D. Transplacental transmission from infected dams to their calves
Vertical transmission is highly efficient, so infected heifers born to infected dams perpetuate infection even without dogs. Neospora is not venereal or tick-borne in cattle, and cattle do not eat meat.
Further reading: Constable et al., Veterinary Medicine (11th ed.)
A beef herd using natural service has low pregnancy rates, many cows returning to service at irregular intervals and a prolonged calving season. The bulls are aged 5–7 years and appear healthy. The most appropriate next step is:
C. Collect preputial smegma from the bulls for Tritrichomonas foetus culture and PCR
Early embryonic death with irregular returns in a naturally bred herd, with older bulls (silent persistent carriers), points to trichomonosis (or campylobacteriosis). Preputial sampling of bulls is the diagnostic step. Neospora typically causes mid-gestation abortion.
Further reading: MSD Veterinary Manual
A 6-month-old pedigree kitten from a cattery has chronic large-bowel diarrhoea with mucus and fresh blood; a fresh wet smear shows organisms with jerky forward motion and an undulating membrane. The most likely organism and treatment are:
C. Tritrichomonas foetus; ronidazole
Jerky motion with an undulating membrane distinguishes T. foetus from the falling-leaf motion of Giardia. Ronidazole is the drug most used (about 30 mg/kg orally once daily for 14 days is widely cited — confirm against the product label and your national formulary), with care over neurotoxicity.
Further reading: Sykes, Greene's Infectious Diseases of the Dog and Cat (5th ed.)
Yellow caseous lesions in the mouth and crop of young pigeons ('canker') are caused by:
D. Trichomonas gallinae
T. gallinae infects the upper digestive tract of pigeons, doves and raptors; squabs are infected through crop milk. Histomonas causes blackhead in turkeys; E. tenella causes caecal coccidiosis.
Further reading: Taylor, Coop & Wall, Veterinary Parasitology (4th ed.)
Accidental access of horses to cattle feed containing monensin is dangerous because:
B. Horses are highly sensitive to ionophore toxicity, which damages cardiac and skeletal muscle
Ionophores disrupt cellular ion gradients; horses have a very low tolerance, and poisoning causes myocardial necrosis and death. Monensin is an ionophore, not a nitroimidazole.
Further reading: MSD Veterinary Manual
In pigs and poultry, the ionophores monensin, narasin and salinomycin should not be given with which drug because of a dangerous interaction?
D. Tiamulin
Tiamulin inhibits the hepatic metabolism of these ionophores, causing toxicity (muscle damage, paralysis, death). Amoxicillin, ivermectin and vitamin E do not produce this interaction.
Further reading: MSD Veterinary Manual
Live coccidiosis vaccines for chickens should not be combined with in-feed anticoccidials because:
C. The drugs would suppress replication of the vaccine strains needed for immunity
Immunity develops from controlled cycling of vaccine Eimeria in the flock; an active anticoccidial would stop this. Vaccines are used in breeders, layers and broilers.
Further reading: Taylor, Coop & Wall, Veterinary Parasitology (4th ed.)
Which clinical sign is typical of histomonosis in turkeys?
A. Sulphur-yellow droppings
Sulphur-yellow droppings with dullness and drooping wings are typical; the dark head is not reliable. Twisted neck suggests Newcastle disease or vitamin deficiency; sinus swelling suggests mycoplasmosis.
Further reading: Taylor, Coop & Wall, Veterinary Parasitology (4th ed.)
Ten here, 37 in the app. The Laisha app has every practice question we have written to NAVLE in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
Free for ten days, then one subscription of US$10 a month. We would rather say so here than have you find it later.
An AI operating system for agriculture: free guides, manuals and tools written for every country.