Seroprevalence of Chlamydia trachomatis types in children with clinical trachoma in New Delhi, India.

Micro-immunofluorescence test with type specific antigens of ocular Chlamydial infection types A-D was used for serotyping the causative C. trachomatis serotypes in 32 inclusion positive school children suffering from trachoma. Single serotype associated infection was seen in six of the patients. The rest of them had antibodies against more than one serotype indicating simultaneous or previous infection by more than one serotype. By geometric mean titre determination, type C appeared to be the most prevalent serotype. However the highest antibody titres in individual cases were most frequently observed for serotype A. The use of geometric mean titre versus highest titre against specific serotype observed in individual cases for population survey is discussed. Isolation of organism for absolute determination of causative serotype from each patient is emphasised.