Acute lower respiratory tract infection due to Chlamydia species in children under five years of age.

Background: The contribution of Chlamydia spp in respiratory tract infections in paediatric population from India has not been studied in detail.

Methods: Sixty children under five years of age who were admitted with acute lower respiratory tract infection during a one year period were investigated for Chlamydial aetiology of respiratory infection. Diagnosis was based on antigen detection by direct immunofluorescence (DIF) in throat swab along with anti-Chlamydial immunoglobulin G (IgG) antibody demonstration by solid phase enzyme immunoassay (EIA).

Results: Chlamydia spp antigen was detected in seven (11.6%) cases, C. pneumoniae in six (10%) and C. trachoniatis in one (1.6%). Chlamydia spp IgG antibody in serum was demonstrated in 24 (40%) cases, of which C. pneumoniae IgG was denconstrated in 18 (30%) cases. Taking the criteria of antigen detection (n=7) and high IgG antibody titre of > or = 1:512 (n=5) for a positive case, 12 (20%) children were found to be suffering from recent Chlamydial infection.

Conclusion: Chlamydia spp plays a significant role in respiratory tract infections in Indian paediatric population. Diagnostic procedure like antigen detection in throat swab is rapid, less cumbersome and feasible and should be more widely used along with antibody demonstration to determine the aetiological agent early in the course of illness.