The disorders affecting primarily the alveolar epithelium and the alveolar space share common histopathological description, with preserved pulmonary architecture, hyperplasia of type 2 AEC, interstitial infiltrates composed of immuno/inflammatory cells and scattered myofibroblasts, and the alveolar space filled with either immuno/inflammatory cells, desquamated materials, or components derived from surfactant lipid and protein complex. In the coming years, it is likely that the list of disorders will expand rapidly with the availability of specific tissue markers. Currently, the following grouping can be proposed: infections, surfactant disorders, and eosinophilic lung diseases. Infections The role of infection, mainly viral, in the development and progression of ILD is sustained by a number of human and experimental reports. From recent knowledge, it is strongly suggested that latent viral infections may be involved in the pathogenesis of ILD, through targeting of the alveolar epithelium. The main virus implicated include adenovirus, members of human herpes virus family (Epstein-Barrr virus and cytomegalovirus), and respiratory syncitial virus [140] . Number of other viruses can also be involved such as Influenza A, hepatitis C, or even Human Immunodeficiency Virus (HIV) in immunocompetent children [141] [142] [143] [144] .