DVM Zoonotic Diseases and Public Health 3 — Questions and Answers
Question 1: Which zoonotic parasite is responsible for causing visceral larva migrans in children and is most commonly associated with dogs?
- Ancylostoma braziliense
- Toxocara canis (Correct answer)
- Dirofilaria immitis
- Echinococcus granulosus
Correct answer: Toxocara canis
Toxocara canis larvae cause visceral larva migrans when ingested by children, migrating through visceral organs including the liver, lungs, and eyes.
Question 2: Cutaneous larva migrans ('creeping eruption') in beach-going humans is most commonly caused by which organism?
- Toxoplasma gondii
- Ancylostoma braziliense (cat/dog hookworm) (Correct answer)
- Strongyloides stercoralis
- Baylisascaris procyonis
Correct answer: Ancylostoma braziliense (cat/dog hookworm)
Ancylostoma braziliense larvae penetrate human skin but cannot complete their life cycle, migrating through the epidermis and causing the characteristic serpiginous track.
Question 3: A veterinarian suspects Cryptosporidium parvum infection in a calf with profuse watery diarrhea. Which group of humans is at HIGHEST risk for severe zoonotic disease from this pathogen?
- Healthy adults with normal immune function
- Pregnant women in the third trimester
- Immunocompromised individuals (HIV/AIDS, transplant recipients) (Correct answer)
- Children under 5 years with intact immunity
Correct answer: Immunocompromised individuals (HIV/AIDS, transplant recipients)
Cryptosporidium parvum causes self-limiting illness in immunocompetent individuals but can be life-threatening and chronic in immunocompromised hosts.
Question 4: Echinococcus granulosus (cystic echinococcosis) is primarily maintained in which epidemiological cycle?
- Dog (definitive) → sheep (intermediate) → dog (Correct answer)
- Cat (definitive) → rodent (intermediate) → cat
- Fox (definitive) → human (dead-end host) → fox
- Wolf (definitive) → deer (intermediate) → wolf
Correct answer: Dog (definitive) → sheep (intermediate) → dog
The classical sylvatic/pastoral cycle of E. granulosus involves dogs as definitive hosts passing tapeworm eggs to sheep as intermediate hosts, with humans as accidental dead-end hosts.
Question 5: The 'One Health' approach to zoonotic disease control emphasizes which core principle?
- Prioritizing human health outcomes over animal and environmental health
- Integrated collaboration across human medicine, veterinary medicine, and environmental health (Correct answer)
- Centralizing disease surveillance under a single governmental agency
- Focusing exclusively on emerging infectious diseases with pandemic potential
Correct answer: Integrated collaboration across human medicine, veterinary medicine, and environmental health
One Health recognizes that human, animal, and environmental health are interconnected and requires collaborative, multisectoral approaches to prevent and control zoonotic diseases.
Question 6: Which of the following statements about Nipah virus is CORRECT from a veterinary public health perspective?
- Pigs are the primary reservoir and infect humans directly in Malaysian outbreaks
- The virus cannot be transmitted human-to-human in any documented case
- Date palm sap contaminated by bats is the only documented transmission route
- Fruit bats are reservoirs; pigs served as amplifying hosts in the 1999 Malaysia outbreak (Correct answer)
Correct answer: Fruit bats are reservoirs; pigs served as amplifying hosts in the 1999 Malaysia outbreak
In the 1999 Malaysia outbreak, Pteropus fruit bats were the reservoir, pigs acted as amplifying hosts transmitting virus to farmers, and culling 1 million pigs halted the outbreak.
Question 7: A public health investigation links multiple human Salmonella Typhimurium cases to a reptile petting zoo. The recommended public health message for visitors should emphasize:
- Avoiding contact with all reptiles permanently
- Handwashing with soap and water immediately after contact with reptiles (Correct answer)
- Using alcohol-based hand sanitizers as the primary preventive measure
- Wearing gloves eliminates the need for handwashing after reptile contact
Correct answer: Handwashing with soap and water immediately after contact with reptiles
Soap and water handwashing is the most effective prevention for Salmonella from reptile contact; alcohol sanitizers are less effective against Salmonella on hands.
DVM Zoonotic Diseases and Public Health 3
Which zoonotic parasite is responsible for causing visceral larva migrans in children and is most commonly associated with dogs?