Edward is 9 months old and is seen with his mother. She is concerned as he has been wheezy for several days with a runny nose but today also has a cough and fever of 37.8°C . His older brother has Asthma. He is maintaining his usual oral intake and is otherwise a happy child.
On chest examination he has mild bilateral wheeze and crackles. Respiratory rate is 45 breaths per minute with other vital signs unremarkable.
What is the most likely diagnosis?