Another potential contributory factor that needed to be ruled out was viral infection of the respiratory tract. Infection with adenovirus or influenza virus must be considered. Adenovirus type 14 is the most likely cause of severe viral pneumonia in adults. Radiographic findings may include lobar infiltrates, although these are more characteristic of bacterial pneumonia [12, 13] . The fact that bacterial infections should have responded to levofloxacin argues against the fact that a secondary bacterial pneumonia superimposed with influenza A or B causing severe pulmonary disease. The lack of recent travel in H5N1 (bird flu) endemic areas or exposure to sick or dead poultry argue against H5N1 influenza (bird flu) [14] .