ETIOLOGY OF ATYPICAL ("VIRUS") PNEUMONIAS

Abstract

During the past few years an increasing amount of attention has been given to a pneumonic syndrome which differs sharply from pneumococcic lobar pneumonia and from other familiar pneumonias of known causation. It has occurred in two general forms, one represented by a small proportion of cases of pneumonic involvement in epidemics of mild disease of the respiratory tract, like those cases described by Bowen,¹ Allen² and most other authors, and the other represented by isolated, sporadic, nonseasonal cases of severe disease, occurring chiefly in persons over 30 years of age. In the former the incubation period appears to be a matter of a few days, and in the latter it is longer, up to two weeks or more. Both forms are characterized by a gradual onset with dry inflammation of parts or all of the mucosa of the respiratory tract; chills or chilliness; slowly rising fever lasting