NAVLE Veterinary Public Health Questions and Answers — Questions and Answers
Question 1: A USDA veterinarian performing post-mortem inspection on a steer carcass finds multiple, well-demarcated, caseous abscesses in the lungs and associated mediastinal lymph nodes. What is the correct disposition for this carcass?
- Pass for human consumption after trimming affected parts.
- Pass for cooking only.
- Condemn the thoracic organs and pass the rest of the carcass.
- Condemn the entire carcass. (Correct answer)
Correct answer: Condemn the entire carcass.
The lesions described (caseous necrosis/granulomas in lungs and associated lymph nodes) are classic for bovine tuberculosis (*Mycobacterium bovis*). According to USDA regulations, evidence of generalized tuberculosis, which includes extensive lesions in the thoracic cavity, requires condemnation of the entire carcass due to its significant zoonotic potential and systemic nature.
Question 2: A pregnant veterinary technician is assisting with a feline dystocia. The queen, a former stray, expels a large amount of brownish placental fluid. The supervising veterinarian should advise the technician that she is at an increased risk of exposure to which zoonotic agent via aerosolization of these birth fluids?
- Toxoplasma gondii
- Bartonella henselae
- Coxiella burnetii (Correct answer)
- Microsporum canis
Correct answer: Coxiella burnetii
*Coxiella burnetii*, the causative agent of Q fever, is shed in extremely high concentrations in the birth products (placenta, amniotic fluid) of infected animals, including cats. Transmission to humans often occurs through the inhalation of infectious aerosols, posing a significant risk to individuals assisting with parturition, especially pregnant women.
Question 3: A new pen-side antigen test for Bovine Respiratory Syncytial Virus (BRSV) is evaluated in a group of 300 calves. The results are as follows: 85 calves that are truly positive for BRSV test positive. 190 calves that are truly negative for BRSV test negative. 15 truly positive calves test negative. 10 truly negative calves test positive. What is the specificity of this new test?
- 85.0%
- 90.9%
- 95.0% (Correct answer)
- 91.7%
Correct answer: 95.0%
Specificity measures a test's ability to correctly identify disease-free individuals. The formula is: Specificity = [True Negatives / (True Negatives + False Positives)] * 100. In this scenario, the True Negatives are 190 and the False Positives are 10. Therefore, Specificity = [190 / (190 + 10)] * 100 = [190 / 200] * 100 = 95.0%.
Question 4: A veterinarian is called to a swine operation to investigate an outbreak of high fever, anorexia, and vesicular lesions on the snouts and coronary bands of multiple pigs. What is the most critical and immediate first action for the veterinarian to take?
- Initiate treatment with broad-spectrum antibiotics to prevent secondary infections.
- Contact the State Veterinarian or USDA-APHIS Area Veterinarian in Charge. (Correct answer)
- Euthanize affected pigs to prevent further spread and collect post-mortem samples.
- Advise the producer to quarantine the farm and ship samples to a local diagnostic lab.
Correct answer: Contact the State Veterinarian or USDA-APHIS Area Veterinarian in Charge.
Vesicular lesions in swine are clinically indistinguishable from Foot-and-Mouth Disease (FMD), a highly contagious and economically devastating foreign animal disease (FAD). The legal and professional obligation of any veterinarian suspecting an FAD is to immediately report it to state and/or federal animal health officials. This action triggers a specific, high-priority response to confirm the diagnosis and contain the potential outbreak.
Question 5: According to USDA-APHIS regulations, which of the following diseases requires IMMEDIATE notification by an accredited veterinarian to state or federal animal health officials if suspected?
- Bovine Viral Diarrhea (BVD)
- Anaplasmosis
- Johne's Disease
- Foot-and-Mouth Disease (FMD) (Correct answer)
Correct answer: Foot-and-Mouth Disease (FMD)
Foot-and-Mouth Disease (FMD) is a highly contagious foreign animal disease (FAD) with severe economic consequences. Under USDA-APHIS regulations, any suspicion of an FAD like FMD is classified as a 'notifiable disease' and must be reported immediately to the State Animal Health Official (SAHO) and/or the USDA Area Veterinarian in Charge (AVIC). The other diseases listed, while potentially reportable under certain state or program rules, do not carry the same immediate, emergency notification requirement as an FAD.
Question 6: A beef cattle producer wishes to use a medicated feed containing chlortetracycline to control an active anaplasmosis infection. What must a veterinarian provide to legally authorize the producer to obtain and use this feed?
- A standard prescription on a state-approved script pad.
- A valid Veterinary Feed Directive (VFD) order. (Correct answer)
- Verbal authorization communicated directly to the feed mill.
- A signed letter on clinic letterhead describing the intended use.
Correct answer: A valid Veterinary Feed Directive (VFD) order.
The FDA classifies chlortetracycline as a medically important antimicrobial. Its use in or on animal feed is regulated under the Veterinary Feed Directive (VFD) final rule. To legally purchase and administer this medicated feed, the producer must have a valid VFD order issued by a licensed veterinarian with whom they have an established veterinarian-client-patient relationship (VCPR).
NAVLE Veterinary Public Health Questions and Answers
A USDA veterinarian performing post-mortem inspection on a steer carcass finds multiple, well-demarcated, caseous abscesses in the lungs and associated mediastinal lymph nodes.
What is the correct disposition for this carcass?