<prompt> Most common cause of lower respiratory tract infection in 3 year old child is -KlebsellaH-influenzaStreptococcal pneumoniaStaphe aureus  <response>: Ans. is c i.e., Streptococcal pneumonia Etiology of pneumonia Viral - RSV, Influenza, parainfluenza, adenovirus Responsible about 40 of casesBacteria - Seen in 23 of pheumoniaFirst 2 month -o Klebsellao Staphe aureus3 month - 3 year -o S. Pneumoniaeo H. Influenzao Staph aureusAfter 3 year -o 5. Pneumoniao Ataph aureus 