NAVLE Past Questions

Question: A cow presents with sudden death, and postmortem examination reveals swollen limbs, crepitus, and icterus. What is the most likely diagnosis?

• A) Clostridial blackleg
• B) Clostridial tetanus
• C) Clostridial malignant edema
• D) Clostridial bacillary hemoglobinuria

Correct Answer: A) Clostridial blackleg

Explanation: Clostridial blackleg causes sudden death, swollen limbs, and crepitus due to gas production in the muscles. It is often seen in young cattle.

Question: A cow presents with sudden death, bleeding from orifices, and bloating after death. What is the most likely diagnosis?

• A) Bacillus anthracis
• B) Mycobacterium bovis
• C) Clostridium tetani
• D) Leptospira interrogans

Correct Answer: A) Bacillus anthracis

Explanation: Anthrax caused by Bacillus anthracis leads to sudden death in cattle, with postmortem bloating and bleeding from orifices.

Question: A person working in a lab handling animal carcasses develops a dark eschar on their arm, along with malaise and respiratory distress. What is the most likely route of transmission?

• A) Cutaneous exposure
• B) Inhalation
• C) Ingestion of infected meat
• D) Aerosolized bacteria from soil

Correct Answer: A) Cutaneous exposure

Explanation: Cutaneous exposure to Bacillus anthracis spores causes a dark eschar at the site of contact.

Question: A child presents with seizures and CNS signs after playing near raccoon feces. Which parasite is the most likely cause?

• A) Baylisascaris procyonis
• B) Ascaris lumbricoides
• C) Toxocara canis
• D) Toxoplasma gondii

Correct Answer: A) Baylisascaris procyonis

Explanation: Baylisascaris procyonis is a zoonotic parasite from raccoon feces, causing CNS signs in humans.

Question: A cow presents with progressive weight loss, cough, and fever. What is the most likely causative agent?

• A) Mycobacterium tuberculosis
• B) Bacillus anthracis
• C) Brucella abortus
• D) Mycobacterium bovis

Correct Answer: D) Mycobacterium bovis

Explanation: Mycobacterium bovis causes bovine tuberculosis, leading to weight loss, cough, and fever in cows.

Question: A person consuming unpasteurized milk develops lymphadenopathy, fever, and respiratory signs. What zoonotic disease is most likely responsible?

• A) Brucella abortus
• B) Mycobacterium bovis
• C) Salmonella spp.
• D) Campylobacter jejuni

Correct Answer: B) Mycobacterium bovis

Explanation: Unpasteurized milk can transmit Mycobacterium bovis, causing lymphadenopathy and respiratory signs in humans.

Question: A cattle farm experiences multiple cases of abortion in cows during the second half of gestation. What is the most likely zoonotic agent?

• A) Brucella abortus
• B) Bacillus anthracis
• C) Bartonella henselae
• D) Salmonella spp.

Correct Answer: A) Brucella abortus

Explanation: Brucella abortus causes abortion in cattle, especially during the second half of gestation.

Question: A veterinarian develops undulant fever, night sweats, and malaise after handling aborted cow fetuses. What is the most likely diagnosis?

• A) Anthrax
• B) Brucella melitensis
• C) Toxoplasmosis
• D) Rabies

Correct Answer: B) Brucella melitensis

Explanation: Brucella melitensis or B. abortus causes undulant fever in humans after exposure to infected animals or their fluids.

Question: A person presents with a small papule at the site of a cat scratch, followed by fever and lymphadenopathy. What is the most likely causative agent?

• A) Bartonella henselae
• B) Yersinia pestis
• C) Pasteurella multocida
• D) Bacillus anthracis

Correct Answer: A) Bartonella henselae

Explanation: Bartonella henselae, the cause of cat scratch fever, leads to lymphadenopathy and fever after a cat bite or scratch.

Question: A horse presents with severe swelling on its nose after being bitten by a rattlesnake. What is the best initial treatment?

• A) Administer antivenom and provide IV fluids
• B) Administer corticosteroids and antibiotics
• C) Administer anti-inflammatories and provide respiratory support
• D) Perform a blood transfusion and provide supportive care

Correct Answer: A) Administer antivenom and provide IV fluids

Explanation: Rattlesnake bites cause swelling, necrosis, and systemic signs. Antivenom and IV fluids are essential for treatment.