title: Spread of subclinical Chlamydia pneumoniae infection in a closed community.
abstract: Chlamydia pneumoniae infections may spread subclinically. The present investigation took place in a military setting. Sera drawn when the conscripts had entered their military service 2 months previously had been kept frozen and were available. In a camp with 500 people, 35 (7%) developed clinical symptoms of pneumonia. The infection was serologically verified with C. pneumoniae-specific micro-immunofluorescence technique. Of 40 healthy controls, 21 turned out to fulfil the serological criteria of infection, thus, representing subclinical cases. These 21 cases, when extrapolated to the whole camp, equalled a rate of 49% which, added to the 7% of pneumonic cases, gave a total infection rate of 56%. Pre-existing IgG antibodies were demonstrated in 10% of the pneumonic cases, 48% of the subclinical cases, and 89% of the non-infected, healthy controls. Without the access to pre-epidemic sera permitting us to establish 4-fold titre rises, the spread of subclinical C. pneumoniae infection would have been noted at 5%, and not 49% as here demonstrated.
authors.affiliation: Norwegian Defence Microbiological Laboratory, Oslo.
authors.forename: B P
authors.initials: BP
authors.lastname: Berdal
authors.forename: O
authors.initials: O
authors.lastname: Scheel
authors.forename: A R
authors.initials: AR
authors.lastname: Ogaard
authors.forename: T
authors.initials: T
authors.lastname: Hoel
authors.forename: T J
authors.initials: TJ
authors.lastname: Gutteberg
authors.forename: G
authors.initials: G
authors.lastname: Anestad
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D002690:Chlamydia Infections / Q000453:epidemiology* / Q000276:immunology / Q000635:transmission*; D016993:Chlamydophila pneumoniae / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008889:Military Personnel; D009664:Norway / Q000453:epidemiology; D011014:Pneumonia / Q000453:epidemiology* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G