This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Medicine
Best method to diagnose typhoid in the first week is ? 
Select and explain. 
A. Blood cultrue, B. Bone marrow cultrue, C. Urine culture, D. Stool culture
B: Bone marrow cultrue
Answer: B: Bone marrow cultrue 
Explanation: Blood, intestinal secretions (vomitus or duodenal aspirate), and stool culture results are positive for S typhi in approximately 85%-90% of patients with typhoid fever who present within the first week of onset. They decline to 20%-30% later in the disease course Ref Harrison20th edition pg 1079