This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
A 'case' in TB is defined as - 
Select and explain. 
A. X-ray positive, B. Culture positive, C. Sputum AFB positive, D. Tuberculosis positive
C: Sputum AFB positive
Answer: C: Sputum AFB positive 
Explanation: - the case in tuberculosis is defined as the one in which sputum positive for acid fast bacilli is detected. Reference: Park's textbook of preventive and social medicine, 23rd edition, pg no:182 <\p>