The clinical spectrum of endemic psittacosis.

Psittacosis may present with a wide variety of clinical manifestations. This fact has received attention in the literature 1-4 but, in our experience, is not generally appreciated by either house officers or practicing physicians. Unless a high level of suspicion is maintained, those cases occurring in other than epidemic situations may be missed. Recent experience with several patients prompted a review of the cases of psittacosis seen at the Vanderbilt University Hospital during the past decade. This review reinforced the impression that the sporadic form of psittacosis is diverse in its presentation and is often overlooked as a diagnostic possibility. This paper summarizes our experience with endemic psittacosis and emphasizes its clinical variability, the frequency with which it mimics bacterial pneumonia, and its occasional failure to respond promptly to tetracycline therapy. Summary of Cases Nine cases have been observed at the Vanderbilt University Hospital since 1955, when facilities for the