DVM Doctor of Veterinary Medicine Zoonotic Diseases and Public Health Questions and Answers — Questions and Answers
Question 1: An unvaccinated, 4-year-old domestic dog is presented to your clinic after biting a child. The dog appears healthy on examination. According to the guidelines from the Compendium of Animal Rabies Prevention and Control, what is the most appropriate action to take regarding the dog?
- Administer a rabies vaccine immediately and quarantine the dog at the owner's home for 45 days.
- Euthanize the animal immediately and submit the head for rabies testing.
- Confine and observe the animal for 10 days for any signs of rabies. (Correct answer)
- Release the animal to the owner with instructions for strict home confinement for 30 days.
Correct answer: Confine and observe the animal for 10 days for any signs of rabies.
For a healthy dog, cat, or ferret that bites a person, the animal should be confined and observed for 10 days, regardless of its vaccination status. This 10-day period is sufficient to determine if the virus was present in the saliva at the time of the bite. If the animal remains healthy, it could not have transmitted rabies. Euthanasia is not indicated unless signs suggestive of rabies develop during the observation period. Post-exposure vaccination of the animal is not performed during the 10-day observation period to avoid confusing potential vaccine reactions with signs of rabies.
Question 2: A client who is pregnant is concerned about acquiring toxoplasmosis. She has two indoor-only cats and wants to know the best way to minimize her risk. While advising her to avoid cleaning the litter box, you also explain the most common route of transmission to humans. Which of the following is the most common way people become infected with *Toxoplasma gondii*?
- Inhaling aerosolized oocysts from cat litter.
- Being bitten or scratched by an infected cat.
- Eating undercooked meat containing tissue cysts. (Correct answer)
- Direct contact with an infected cat's fur.
Correct answer: Eating undercooked meat containing tissue cysts.
While infection from oocysts in cat feces is a significant concern, especially for pregnant women, the most common route of human infection globally is through the consumption of undercooked or raw meat (like pork, lamb, or venison) that contains *Toxoplasma* tissue cysts. Ingestion of food or water contaminated with oocysts from cat feces is another primary route, but eating contaminated meat is generally considered the most frequent source of infection in many human populations. Transmission via inhalation, bites, scratches, or contact with fur is not a recognized route of infection.
Question 3: A public health official contacts you about several people who have developed an acute flu-like illness with fever and pneumonia. Their only common link is the consumption of raw milk from a local goat dairy where you recently attended a difficult kidding. Which zoonotic pathogen is the most likely cause of this outbreak?
- Brucella melitensis
- Listeria monocytogenes
- Mycobacterium bovis
- Coxiella burnetii (Correct answer)
Correct answer: Coxiella burnetii
*Coxiella burnetii*, the causative agent of Q fever, is the most likely pathogen. It is shed in high concentrations in the milk, urine, feces, and especially the birth products (placenta, amniotic fluid) of infected ruminants like goats, sheep, and cattle. Human infection often occurs via inhalation of contaminated aerosols, which are heavily generated during parturition, or through consumption of unpasteurized dairy products. The clinical signs of acute Q fever in humans, including fever, pneumonia, and flu-like symptoms, match the scenario. While the other pathogens are zoonotic, *C. burnetii* is classically associated with this specific combination of exposure (kidding, raw milk) and clinical presentation.
Question 4: Which of the following is a World Organisation for Animal Health (WOAH, formerly OIE) listed disease with major public health and international trade implications, requiring immediate notification by member countries?
- Bovine Viral Diarrhea (BVD)
- Bovine Spongiform Encephalopathy (BSE) (Correct answer)
- Infectious Bovine Rhinotracheitis (IBR)
- Canine Distemper Virus
Correct answer: Bovine Spongiform Encephalopathy (BSE)
Bovine Spongiform Encephalopathy (BSE), also known as "Mad Cow Disease," is a WOAH-listed disease due to its proven zoonotic potential (causing variant Creutzfeldt-Jakob disease in humans) and its devastating impact on international trade of cattle and bovine products. Its detection triggers significant regulatory and public health responses. While BVD and IBR are economically important cattle diseases, and Canine Distemper is a serious viral disease in dogs, they do not have the same level of international public health and trade implications as BSE and are managed differently under WOAH guidelines.
Question 5: A local wildlife rehabilitator is concerned after finding a "raccoon latrine" in a children's play area. You advise on the serious risk of neural larva migrans in humans, which can be caused by the ingestion of eggs from which parasite?
- Toxocara canis
- Ancylostoma caninum
- Trichinella spiralis
- Baylisascaris procyonis (Correct answer)
Correct answer: Baylisascaris procyonis
*Baylisascaris procyonis*, the raccoon roundworm, is a well-documented cause of severe and often fatal neural larva migrans (NLM), as well as ocular and visceral larva migrans in humans and other animals. Raccoons are the definitive host and often defecate in communal latrines, leading to heavy environmental contamination with eggs. The larvae of *B. procyonis* are particularly dangerous because they are large, aggressive, and continue to grow as they migrate through the central nervous system. While *Toxocara canis* (dog roundworm) can also cause larva migrans, *B. procyonis* is uniquely associated with raccoons and is known for causing more severe neurologic disease.
Question 6: Which of the following scenarios best exemplifies the "One Health" approach to public health?
- A veterinarian treating a dog's skin infection with a course of antibiotics.
- A research project exclusively studying the genetic mutations of a specific animal virus.
- A program where veterinarians, physicians, and ecologists collaborate to study West Nile Virus by monitoring bird populations, mosquito vectors, and human cases. (Correct answer)
- A public campaign focused solely on increasing the rate of rabies vaccination in domestic dogs.
Correct answer: A program where veterinarians, physicians, and ecologists collaborate to study West Nile Virus by monitoring bird populations, mosquito vectors, and human cases.
The One Health concept is an integrated, unifying approach that recognizes that the health of people, animals, and their shared environment are inextricably linked. The collaborative study of West Nile Virus involving veterinarians (animal health), physicians (human health), and ecologists (environmental/vector health) is a classic example. This approach addresses the disease at the human-animal-environment interface. The other options are important activities within a single discipline but do not represent the interdisciplinary, collaborative approach that defines One Health.
DVM Doctor of Veterinary Medicine Zoonotic Diseases and Public Health Questions and Answers
An unvaccinated, 4-year-old domestic dog is presented to your clinic after biting a child.
The dog appears healthy on examination.
According to the guidelines from the Compendium of Animal Rabies Prevention and Control, what is the most appropriate action to take regarding the dog?