A patient who is suspected of having acute viral hemorrhagic fever reveals history of tick bite. Which of the following is the most possible causative agent?

Correct Answer: C

Rationale: Crimean Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus transmitted primarily by Hyalomma ticks, making it the most likely causative agent in a patient with a history of tick bite and symptoms of viral hemorrhagic fever (fever, bleeding). Hantavirus (A) is rodent-borne, Rift Valley virus (B) is mosquito-borne, and Marburg virus (D) is bat-associated, none of which align with tick transmission. Ross River virus (E) is mosquito-borne and not a hemorrhagic fever. Thus, CCHFV (C) is the correct answer.

Correct Answer: B

Rationale: Reticulocytes (B) are immature RBCs released from bone marrow during active erythropoiesis, increasing with iron therapy in iron deficiency anemia. Myelocytes (A) are myeloid precursors, ring sideroblasts (C) indicate sideroblastic anemia, target cells (D) suggest liver/hemoglobinopathy, and megakaryoblasts (E) are platelet precursors—reticulocytes directly reflect erythropoiesis.

Correct Answer: D

Rationale: Artemisinin treats chloroquine-resistant falciparum malaria due to rapid schizonticidal activity (D), killing asexual blood-stage parasites. It’s not primarily gametocidal (A), doesn’t affect hypnozoites (B), isn’t sporontocidal (C), and doesn’t block ring-to-gametocyte (E)—schizonticide action is key.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.