Medical Microbiology Test Bank

Correct Answer: A

Rationale: The most probable diagnosis is Dermatotropic leishmaniasis. The roundish ulcers, lymph node enlargement, and presence of unicellular aflagellar organisms in discharge are characteristic of this parasitic infection transmitted by sandfly bites. Leishmania parasites cause skin lesions and lymphadenopathy. Toxoplasmosis (B) presents with flu-like symptoms, not ulcers. Scabies (C) causes intense itching and burrows, not ulcers. Trypanosomiasis (D) presents with fever, not ulcers. In this case, the symptoms align closely with Dermatotropic leishmaniasis, making it the most likely diagnosis.

Correct Answer: A

Rationale: The most probable diagnosis is Dermatotropic leishmaniasis. The roundish ulcers, lymph node enlargement, and presence of unicellular aflagellar organisms in discharge are characteristic of this parasitic infection transmitted by sandfly bites. Leishmania parasites cause skin lesions and lymphadenopathy. Toxoplasmosis (B) presents with flu-like symptoms, not ulcers. Scabies (C) causes intense itching and burrows, not ulcers. Trypanosomiasis (D) presents with fever, not ulcers. In this case, the symptoms align closely with Dermatotropic leishmaniasis, making it the most likely diagnosis.

Correct Answer: B

Rationale: The correct answer is B: Malaria. Fever developing 2 weeks post-blood transfusion is characteristic of malaria due to the incubation period of the parasite. Trypanosomiasis presents earlier, amebiasis usually causes GI symptoms, and toxoplasmosis typically manifests with flu-like symptoms. Malaria is the most likely cause based on the timing and clinical presentation.

Correct Answer: D

Rationale: The correct answer is D because the flu vaccine mainly stimulates systemic immunity, not local immunity. Systemic immunity refers to the immune response throughout the body, while local immunity is specific to a certain area. Choice A is incorrect because the flu vaccine is indeed recommended. Choice B is incorrect as the flu vaccine can be a subunit vaccine, containing only specific antigens. Choice C is incorrect as the flu vaccine is typically administered parenterally, meaning through injection, nasal spray, or oral routes.

Correct Answer: C

Rationale: The correct answer is C: crateriform. In a gelatin stab, a saucer-shaped liquefaction indicates a depression or crater-like shape. This term accurately describes the appearance of the liquefaction. A: napiform means turnip-shaped, which is not relevant to the shape in a gelatin stab. B: saccate means pouch-like, which does not match the saucer-shaped description. D: stratiform refers to something in layers, which is not applicable to the shape of the liquefaction. Therefore, C is the most appropriate term to describe the saucer-shaped liquefaction in a gelatin stab.