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Canadian Journal of Infectious Diseases
Volume 4, Issue 1, Pages 43-46
http://dx.doi.org/10.1155/1993/536180
Original Article

An epidemic of Mycoplasma pneumoniae in Manitoba: A Serological Report

Laila Sekla, Walter Stackiw, Gudrun Eibisch, and Donna Kolton

Cadham Provincial Laboratory, Winnipeg, Manitoba, Canada

Received 9 October 1991; Accepted 15 November 1991

Copyright © 1993 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives: To report an epidemic of Mycoplasma pneumoniae in Manitoba and to discuss the limitations of the serodiagnostic tests used.

Design: A retrospective analysis of the results of a province-wide serological testing for respiratory infections caused by M pneumoniae, using a complement fixation test and an indirect immunofluorescent antibody test for the detection of immunoglobulin (Ig) M antibodies.

Material: From April 1, 1987, to March 31, 1991, 12,804 sera were tested and a serological diagnosis of recent M pneumoniae infections were established in 509 (3.97%). From April 1 to September 30, 1991, an additional 2088 persons were tested; the 158 (7.5%) recent cases of M pneumoniae were subjected to analysis.

Results: Compared with the previous three years, an increase in the number of recent cases of M pneumoniae was first noticed in July 1990 which persisted until September 1991. Of 856 single sera tested, 59 (6.8%) were recent M pneumoniae infections and 56 (96.1%) of these were positive for IgM antibodies. Of the 616 persons who submitted paired sera, 99 (16%) were recent infections, but only 46 (46.4%) had IgM antibodies. Primary infections (ie, positive for IgM antibodies) were detected in 102 (64.5%) and reinfections (ie, positive complement fixation test only) in the remaining 56 persons with recent M pneumoniae infections. Primary infections were detected more frequently in the ‘under 16’ than in the ‘over 16’ year age group (75% versus 55.8% of the recent cases of M pneumoniae in each age group). Reinfections were more common in the older age group. Of the 158 recent cases of M pneumoniae, 30.3% had a pneumonia; of these, 21 (55.2%) were under the age of 16 years.

Discussion: M pneumoniae is an important cause of morbidity. Serological tests are used for the diagnosis despite their limitations. The detection of IgM antibodies in acute serum establishes a diagnosis of primary M pneumoniae; however, their absence does not exclude M pneumoniae. A second (convalescent) blood test is required to diagnose all primary infections. To diagnose all reinfections, paired sera should be tested by complement fixation.

Summary: Manitoba experienced an epidemic of M pneumoniae in 1990–91. Properly selected serological tests can provide a specific and rapid diagnosis.