Hello there, It is very important to always correlate a chest X ray or any radiograph with correct clinical history. remember that an X ray chest , though looking apparently abnormal may not have any relevance if your child s clinical history is not suggestive or correlating to the findings. If there has been ongoing fever, cough, apathy and/or breathing difficulty, and X ray shows mottling in both lungs, it suggest lower respiratory tract infection. Is there any other family member with similar complaints ? Is it the first bout of respiratory symptoms in the child ? All these questions need to be answered before you have a better idea of whether it is bacterial or viral infection. After getting a complete blood count, initiation of appropriate antibiotics can be done. Take care.