Epidemic patterns and carriage of Chlamydia pneumoniae in Norway

Chlamydia pneumoniae infection, in earlier days misdiagnosed as ornithosis, is very common in Norway. The disease develops slowly, a feature that may account for the very large number of subclinical cases, which may be seven fold more common than clinical cases. Subclinical cases produce an antibody response similar to that seen in overt clinical disease. Silent carriage of C. pneumoniae in healthy individuals may be frequent. Therapy based on positive cell culture or polymerase chain reaction (PCR) in the absence of pneumonic symptoms may be questionable. PCR has, however, given the slow development of disease, revealed itself as a handy epidemiological technique useful for the survey of healthy populations.