Dengue is a common vector-borne disease prevalent in tropical countries. Which of the following statement is true for dengue fever?

Correct Answer: B

Rationale: The correct answer is B because once a mosquito vector, usually Aedes aegypti, is infected with the dengue virus, it remains infective for life. This is due to the virus establishing a lifelong infection in the mosquito's salivary glands. A: Incorrect. Dengue is caused by an RNA virus, specifically the flavivirus. C: Incorrect. Aedes mosquitoes prefer clean, stagnant water for breeding, not polluted water. D: Incorrect. Joint symptoms are common in both dengue fever and chikungunya, but usually more severe in chikungunya.

Correct Answer: D

Rationale: In thrombasthenia, there is a deficiency or dysfunction of integrin αIIbβ3 (GPIIb/IIIa), leading to impaired platelet aggregation. Prolonged bleeding time (A) is seen due to defective platelet function. Platelet count (B) is typically normal as thrombasthenia does not affect platelet production. Platelet aggregation defect (C) is a characteristic feature of thrombasthenia. Prolonged clotting time (D) is not associated with thrombasthenia as it primarily affects platelet function, not the coagulation cascade. Hence, choice D is the correct answer.

Correct Answer: A

Rationale: Henoch Schonlein purpura is characterized by palpable purpura, abdominal pain, arthritis, and acute diffuse glomerulonephritis. Thrombocytopenia is not typically associated with Henoch Schonlein purpura, making choice A correct. Thrombocytopenia is more commonly seen in conditions like immune thrombocytopenic purpura. Choices B, C, and D are incorrect as palpable purpura, intussusception, and acute diffuse glomerulonephritis are commonly associated with Henoch Schonlein purpura.

Correct Answer: A

Rationale: The correct answer is A: hyperchlorhydria. Pernicious anemia is characterized by vitamin B12 deficiency due to impaired absorption, not excess stomach acid. Premature graying of hair is unrelated. Presence of anti-intrinsic factor antibody and risk of gastric polyps are associated with pernicious anemia, but not hyperchlorhydria. Therefore, choice A is the correct answer as it does not align with the typical symptoms and characteristics of pernicious anemia.

Correct Answer: D

Rationale: Plat. transfusion is not indicated in immunogenic thrombocytopenia (ITP) because it is an autoimmune disorder where the body destroys its own platelets. Transfusing platelets won't solve the underlying issue of platelet destruction. In aplastic anemia (A), platelet transfusion can help due to low platelet production. In uremia with bleeding (B) and DIC (C), platelet transfusion is necessary to manage bleeding due to decreased platelet function or consumption.