[Chlamydia pneumoniae infection in a family]

HISTORY AND SYMPTOMS: For 11 weeks a 38-year-old woman had suffered from a respiratory infection with peribronchitis, nocturnal coughing fits and earache.

The Chlamydia-CFR titre was raised. Subsequent throat swabs of her husband and two daughters grew Chlamydia pneumoniae (C.p.), but not in her case; 5 days earlier she had been started on roxithromycin. 3 weeks before the patient fell ill her two daughters had a flu-like illness with cough and subfebrile temperature and her husband also had flu-like symptoms, which regressed after few days. Antibiotic treatment with roxithromycin improved the symptoms in the mother and older daughter, but the younger daughter was not given treatment because she had no symptoms at the time the microorganism had been isolated. She developed joint symptoms, like those of reactive arthritis, 12 weeks after the mother's illness had begun, and conjunctivitis 5 weeks later.

It is likely that the daughters had the C.p. infection first and then infected their parents. While the father's and older daughter's illness quickly regressed, the mother became quite ill. Her serology was positive for a primary infection in adulthood, but in the daughters the serology was negative and, despite demonstration of the organism, the diagnosis of acute C.p. infection could not be made.