POSSIBLE NOSOCOMIAL TRANSMISSION OF PSITTACOSIS

OBJECTIVES: To investigate a cluster of seven pneumonia cases among pe rsons exposed to a pet-shop worker hospitalized with psittacosis. DESI GN: Epidemiological study of the outbreak, sere-diagnostic evaluation of exposed persons with pneumonia; and retrospective review of the pne umonia cases. SETTING: 450-bed teaching community hospital. PARTICIPAN TS: Employees of the nursing unit where the patient with psittacosis w as hospitalized. RESULTS: The index case had laboratory and clinical e vidence of psittacosis. Four of the seven exposed persons who develope d pneumonia had serologic results that met criteria for a diagnosis of psittacosis, and three met criteria for Chlamydia pneumoniae infectio n, possibly reflecting cross-reactivity between the microimmunofluores cence assays for the two diseases. The epidemiological graph suggested a relationship between the index case and the cluster of pneumonias i n exposed individuals. CONCLUSIONS: Psittacosis may have been transmit ted person to person in a hospital setting.