Mr XY was found to be anemic. During history taking, he informed his doctor that he was a strict vegetarian who did not consume any meat, fish or milk products.

Correct Answer: B

Rationale: The correct answer is B: Vitamin B12 deficiency. As a strict vegetarian who does not consume any meat, fish, or milk products, Mr XY is at risk for Vitamin B12 deficiency. Vitamin B12 is primarily found in animal products and is essential for red blood cell production. Anemia can result from Vitamin B12 deficiency, leading to symptoms such as fatigue and weakness. Iron deficiency (A) is also common in vegetarians, but in this case, the focus is on Vitamin B12 due to the exclusion of all animal products. Defects in erythropoietin production (C) are not related to Mr XY's dietary choices. Calcium-deficiency (D) is not directly related to anemia in this scenario.

Correct Answer: D

Rationale: Step-by-step rationale for why choice D (Infectious mononucleosis) is correct: 1. Infectious mononucleosis is caused by the Epstein-Barr virus. 2. Dohle bodies are seen in the peripheral blood of patients with infectious mononucleosis. 3. These bodies represent aggregates of rough endoplasmic reticulum in neutrophils. 4. The appearance of Dohle bodies is attributed to the viral infection in infectious mononucleosis. Summary: A: Chronic myeloid leukemia - Dohle bodies are not typically seen in this condition. B: Leukemoid reaction - Dohle bodies are not specific to a leukemoid reaction. C: Chediak-Higashi syndrome - This syndrome is characterized by giant granules in neutrophils, not Dohle bodies.

Correct Answer: C

Rationale: The correct answer is C: Temporary collecting of water in jungles. Anopheles balabacensis is a forest-dwelling mosquito species commonly found in jungle environments. They prefer to breed in temporary water collections such as rainwater puddles, small ponds, or stream edges within the jungle. Breeding in urban areas, drains, or rock pools would not be typical for this species based on its natural habitat preference. Therefore, the most suitable breeding site for this vector in Sabah would be temporary water collections in jungles.

Correct Answer: D

Rationale: The correct answer is D: haemolysis. In thalassemia, there is an abnormality in hemoglobin production leading to the destruction of red blood cells, causing hemolysis. This results in the release of bilirubin, leading to jaundice. Iron deposition in the liver (choice B) is seen in conditions like hemochromatosis, not thalassemia. Viral hepatitis B and C (choices A and C) can cause jaundice, but they are not the commonest cause in thalassemia patients, as hemolysis is the primary mechanism in this population.

Correct Answer: C

Rationale: Basophilic stippling refers to the presence of blue-staining granules in red blood cells, which is a classic finding in chronic lead poisoning due to the inhibition of heme synthesis. In CML, the primary feature is the presence of the Philadelphia chromosome. Myelosclerosis is characterized by bone marrow fibrosis, not basophilic stippling. Iron deficiency anemia typically presents with microcytic hypochromic red blood cells, not basophilic stippling. Therefore, the correct answer is C: chronic lead poisoning.