National Licensure Examination for Veterinarians (NLEV) · Nepal · Nepal Veterinary Council (NVC Act 2055 BS)
Original practice questions written to the published syllabus · not past papersPoisoning by metals, plants, mycotoxins, pesticides, non-protein nitrogen, venoms and pollutants, with residues in food and the antidotes used.
In the exams: AVE Paper 1 toxicology at least 3; SAVC toxicology 10 (plus southern African plant poisonings); ICAR AIEEA-PG 13 Unit IV (poisonous plants, agro-chemicals); ICAR AICE-JRF core group 07
How our questions for National Licensure Examination for Veterinarians spread across the units of Veterinary Toxicology. Difficulty: 18 easy, 2 medium, 0 hard.
| Metal toxicity: lead, arsenic and mercury | 2 | |
| Copper, molybdenum, fluorine and selenium toxicity | 2 | |
| Oxalate, lantana and bracken poisoning | 2 | |
| Rodenticide poisoning | 2 | |
| Snake bite and insect stings | 2 | |
| Ecotoxicology and residues | 2 | |
| Cyanogenic plants | 1 | |
| Nitrate and nitrite poisoning | 1 | |
| Mycotoxins and aflatoxicosis | 1 | |
| Organophosphate and carbamate poisoning | 1 | |
| Organochlorine and pyrethroid poisoning | 1 | |
| Urea and non-protein nitrogen toxicity | 1 | |
| Water-borne toxicities | 1 | |
| Antidotes | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Aflatoxins are produced mainly by
C. Aspergillus flavus and A. parasiticus
Aspergillus flavus and A. parasiticus produce aflatoxins on groundnuts, maize and cottonseed. Claviceps produces ergot; Fusarium graminearum zearalenone and deoxynivalenol.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Organophosphates produce toxicity mainly by
A. Inhibiting acetylcholinesterase
OPs phosphorylate acetylcholinesterase, so acetylcholine accumulates at synapses. GABA-A block is the action of cyclodiene organochlorines.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Tetanic extensor seizures triggered by noise or touch, with a 'sawhorse' stance, suggest poisoning by
C. Strychnine
Strychnine antagonises glycine at spinal inhibitory synapses, so stimuli trigger extensor spasms. Metaldehyde seizures, in contrast, are not stimulus-induced.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Groundwater naturally high in which element is a major livestock and human problem in parts of Bangladesh and West Bengal?
D. Arsenic
Geogenic arsenic in shallow tube-well water affects people and livestock in the Bengal delta.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
LD50 is best defined as
A. The statistical dose that kills 50% of a test group by a set route and time
LD50 is a quantal measure of acute lethality. The ED50 is the effective dose in 50%, and the highest dose without adverse effect is the NOAEL.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
The withdrawal period of a veterinary drug is
C. Time from last dose until meat, milk or eggs are usable, with residues below the MRL
The withdrawal (withholding) period is set so residues fall below the maximum residue limit; it applies to the labelled species, dose and route.
Further reading: Gupta, Veterinary Toxicology (3rd ed.); Merck Veterinary Manual, Toxicology
Ten here, 20 in the app. The Laisha app has every practice question we have written to National Licensure Examination for Veterinarians 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.
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