Primary Atypical Pneumonia

During the past few years there has been recognized, with increasing frequency, an respiratory infection associated with peculiar pulmonary lesions.1The vast majority of these cases have occurred among young adults, especially at colleges,2among hospital staffs3and in army camps.4Inability to isolate a common pathogenic bacterium has led to the use of the term virus pneumonia. Numerous designations, including current bronchopneumonia of unusual and undetermined etiology, atypical pneumonia with leukopenia, pneumonitis, acute influenzal pneumonia, acute diffuse and a variety of other names have been used in reporting similar cases. Actually, none of these terms adequately describe the pathologic picture. It would, we believe, be more nearly correct to call this disease an acute bronchiolitis with associated atelectasis. Our purpose in this report is to emphasize the epidemiologic importance of the disease, to consider its clinical features with special reference to the roentgenologic