[Severe pneumonia with a pneumococcal aspect during an ornithosis outbreak]

To describe the clinical, radiological and biological features of Chlamydia psittaci pneumonia.

A pneumonia outbreak occurred in a healthy middle-aged population working in a poultry slaughterhouse. Systematic serology (2 samples at 5 weeks intervals) provided the diagnosis of Chlamydia psittaci pneumonia in 6 patients. Patient files were analyzed retrospectively.

The clinical presentations in this series of pneumonia were particularly homogeneous with a pneumococcal profile in all 6 cases: sudden onset, temperature above 39 degrees C, lobar alveolar involvement, hypoxemia, hyperleukocytosis and liver dysfunction. One case of hallucinatory delirium was observed. The patients were given spiramycin (9 million units per day for 3 weeks) and all recovered rapidly with no complications.

The unusual virulence of the Chlamydia psittaci and very important inoculum were probably involved in this outbreak because of the severity of the pulmonary features and the short exposure of some patients to the bacteria. These cases suggest that the prevention of ornithosis in poultry slaughterhouses should be reinforced.