ENARE multiprofessional residency: Veterinary Medicine · Brazil · EBSERH / FGV
Original practice questions written to the published syllabus · not past papersWater and air hygiene, waste and carcass disposal, disinfection, pollution and climate change as they affect animal and human health.
In the exams: NAVLE environmental health and safety 5%
How our questions for ENARE multiprofessional residency spread across the units of Environment & Environmental Hygiene. Difficulty: 23 easy, 46 medium, 7 hard.
| Water hygiene | 13 | |
| Air hygiene | 12 | |
| Disinfection | 12 | |
| Waste management on livestock farms | 10 | |
| Experimental animal medicine | 9 | |
| Environmental pollution | 7 | |
| Climate change and livestock | 5 | |
| Carcass disposal | 4 | |
| Biomedical waste | 4 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
The result of the multiple-tube fermentation test for coliforms is expressed as:
C. Most probable number per 100 mL
Tube results are converted with statistical tables to a most probable number per 100 mL. Colony counts per 100 mL come from membrane filtration, not from tubes; plaque counts are for phages and viruses.
Further reading: APHA Standard Methods for the Examination of Water and Wastewater
Feedlot steers develop blindness, head pressing and recumbency in a hot spell. The diet is standard, but a new well supplies drinking water. Which water analysis is most relevant?
C. Sulphate concentration, for sulphur-associated polioencephalomalacia
High-sulphate water adds to dietary sulphur; rumen reduction to hydrogen sulphide causes polioencephalomalacia, with blindness and head pressing, and intake (and risk) rises in hot weather. Fluorosis is chronic and affects teeth and bone, not acute neurology. Hardness mainly scales pipes; turbidity does not measure algal toxins.
Further reading: Merck Veterinary Manual, Polioencephalomalacia; NRC water quality guidance
Why does high atmospheric ammonia increase respiratory disease in housed pigs and poultry?
A. It damages the mucociliary escalator, so inhaled pathogens are cleared less well
Ammonia irritates and damages the respiratory epithelium and slows ciliary clearance, so organisms such as Mycoplasma and Pasteurella establish more easily. It is a chemical irritant, not an infectious agent, and does not neutralise antibodies.
Further reading: Wathes & Charles, Livestock Housing
In a BOD test, 6 mL of dairy effluent is diluted to 300 mL. Dissolved oxygen is 8.6 mg/L at the start and 3.4 mg/L after 5 days at 20 °C. What is the BOD5 of the effluent?
C. 260 mg/L
BOD = (DO initial − DO final) / P, where P = 6/300 = 0.02. BOD = (8.6 − 3.4) / 0.02 = 5.2 / 0.02 = 260 mg/L. 5.2 forgets the dilution; 255 uses 6/294 (sample to diluent) instead of sample to total volume; 52 uses a factor of 10.
Further reading: APHA Standard Methods
For efficient aerobic composting of manure, the starting carbon to nitrogen ratio should be about:
B. 25–30 : 1
A C:N of about 25–30:1 balances microbial energy (carbon) and protein (nitrogen) needs. Ratios as low as 5:1 lose nitrogen as ammonia; at 100:1 composting is slow because nitrogen limits microbial growth.
Further reading: On-farm composting handbooks (NRAES-54)
Which practice is the commonest cause of needlestick injuries in veterinary clinics and should be avoided?
C. Recapping used needles by hand
Recapping by hand is a major cause of needlestick injury; the used needle should go straight into a sharps container placed at the point of use. The other practices reduce injuries.
Further reading: Occupational safety guidance for veterinary practice
How many mL of 5% sodium hypochlorite solution are needed to make 10 L of a solution containing 200 ppm available chlorine?
D. 40 mL
5% = 50,000 ppm. C1V1 = C2V2: 50,000 × V1 = 200 × 10,000 mL, so V1 = 40 mL. 4 mL treats 5% as 500,000 ppm; 400 mL treats 5% as 5,000 ppm (a factor-of-ten slip); 20 mL halves the target.
Further reading: Standard dilution arithmetic
Culicoides midges, vectors of bluetongue virus, are best reduced on a farm by:
D. Housing animals at dusk and dawn in the vector season and reducing wet breeding sites
Culicoides breed in wet, organic-rich mud and dung and are most active at dusk and dawn; housing at those times and managing breeding sites reduces biting. Formaldehyde fumigation or water additives do not affect outdoor midge populations.
Further reading: Bluetongue control guidance
Excretion of macrocyclic lactone parasiticides in dung is an environmental concern mainly because:
D. Residues harm dung beetles and other dung fauna, slowing dung breakdown
Macrocyclic lactone residues in dung are toxic to dung-breeding insects, especially some beetles and flies, which slows dung degradation on pasture. They do not produce toxic gas or raise nitrate.
Further reading: Veterinary parasitology and ecotoxicology literature
Which laboratory species, like primates, requires dietary vitamin C because it cannot synthesise it?
D. Guinea pig
Guinea pigs lack L-gulonolactone oxidase and develop scurvy without dietary vitamin C. Rats, mice and rabbits synthesise their own.
Further reading: Laboratory animal medicine texts
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