Primary atypical pneumonia, or viral pneumonia, is not a new disease but has come into prominence because of its probable increased incidence, its lack of response to sulfonamide drugs and the more generalized use of roentgen therapy. The morbidity of this disease is at the present time four times that of the pneumococcic lobar type of pneumonia.1 According to reports of the United States Army, the incidence of the disease is about 20 to 25 per cent of that of all infections of the respiratory tract2 and above 50 and perhaps as high as 75 to 80 per cent of that of all pulmonary lesions.3 In the United States Navy the morbidity exceeds the figure for 1942, which was 2.79 per thousand.4 The loss of time in 738 cases in the air corps amounted to 20,000 man days, or 55 man years.
This disease, like
SCHMITZ RC. PRIMARY ATYPICAL PNEUMONIA OF UNKNOWN CAUSE. Arch Intern Med (Chic). 1945;75(4):222-232. doi:10.1001/archinte.1945.00210280010002