Which virus is the most common cause of acute bronchiolitis in infants under 1 year old

Which virus is the most common cause of acute bronchiolitis in infants under 1 year old

Which virus is the most common cause of acute bronchiolitis in infants under 1 year old?

A. Respiratory syncytial virus (RSV)

B. Influenza virus

C. Adenovirus

D. Rhinovirus

Answer: A

Explanation: RSV is the predominant pathogen causing acute bronchiolitis in young infants, peaking in fall and winter seasons.