Primary Atypical Pneumonia

Primary atypical pneumonia as a clinical entity has only recently received prominent attention. It is usually a mild disease, differing widely from the classic lobar and bronchial pneumonias; it is communicable, has a prolonged period of incubation and is prone to occur in military camps, schools and other groups with frequent intimate contacts. It is a nonbacterial disease. It is characterized by insidious onset, coughing and progressive malaise; there is usually a brief febrile period during which the pulse and the respiration are relatively slow and there is a relative or absolute leukopenia, with minimal early signs of pneumonia but with the rales persisting after the roentgenogram appears normal. There is little evidence that this is a new disease since reports of a similar pneumonia extend back into the nineteenth century. Stansfield, 1 in 1923, discussed the pulmonary involvement in 12 cases of grip. Cole and MacCallum, 2 summarizing data