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
SARS true are - 
Select and explain. 
A. Severe acute respiratory syndrome, B. Documented respiratory route spread, C. Effective vaccine available, D. Cause atypical pneumonitis
A: Severe acute respiratory syndrome
Answer: A: Severe acute respiratory syndrome 
Explanation: The pathophysiology of acute respiratory distress syndrome involves fluid accumulation in the lungs not explained by hea failure (noncardiogenic pulmonary edema). Of these, the pathology most associated with ARDS is DAD, which is characterized by a diffuse inflammation of lung tissue. Ref Harrison20th edition pg 1059