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Editor,—A recent study in Jamaica by Dowe et al using cell culture and a direct fluorescence assay (DFA) showed a prevalence of Chlamydia trachomatis infection in 47% of gynaecological patients.1 Unfortunately, there are no comparable data for cell culture and DFA in Trinidad. Moreover, we cannot find any reports on serological studies for C trachomatis IgG antibody in the West Indies. In an attempt to shed more light on prevalence of C trachomatis IgG antibody in pregnant women in Trinidad, we collected 56 serum specimens (mean age of patients 27 years) with ethics committee approval from one clinic at the general hospital, Port of Spain. As well as testing these sera by an in-house ELISA method based on that described by Ossewaarde et al,2 we also used a commercial ELISA test specific for C trachomatis IgG (Savyon Diagnostics, Israel) and the whole inclusion immunofluorescence (WHIF) test as previously described by Richmond and Caul.3
All collected sera were stored at −70°C until analysis. Samples were subsequently coded and tested blind in duplicate in laboratories in Sheffield and Bristol. Details of the in-house ELISA test methodology and interpretation of readings using microimmunofluorescence (MIF) serum positive and negative controls were described in Keay et al.4 The commercial ELISA was performed according to the manufacturer's instructions. The WHIF test consisted of chlamydial inclusions of infected mammalian cells with LGV2 mounted on a glass well or coverslip. The WHIF titre is described as the highest dilution of antibody where the inclusion can be clearly seen by fluorescence staining.
For the ELISA tests, results were recorded as positive, negative, or equivocal. For the WHIF test, titres between 1:64 and 1:256 were recorded as such; a low titre was ≤1:64 and a high titre ≥1:512.
Twenty five (45%) and 29 (52%) samples were positive for the commercial and in-house ELISA tests respectively. Eighteen (32%) samples had a titre of ≥512 in the WHIF test, as shown in table 1.
The latter finding is of note. It is accepted that C trachomatis is an established pelvic pathogen and in a recent study of 34 women positive for C trachomatis IgG (≥1:128) by ELISA, at laparoscopy 31 (91.2%) were diagnosed as having tubal disease.5 It is likely that significant damage could be occurring in these patients as a previous study looking at high C trachomatis IgG titres showed 46% positive and 8% positive in infertile women with damaged and normal tubes, respectively.6
Although these findings are based on relatively small numbers, they are of significant concern if combined with the other most recent study.1 It would appear that the prevalence rates for C trachomatis may well be high and that data presented here suggest possible future PID development and resultant sequelae. It is clear that further studies are warranted and that screening and treatment strategies may be required urgently to curtail considerable morbidity in Trinidad and throughout the West Indies in general.
High prevalence of C trachomatis IgG antibodies in antenatal patients in Trinidad
Prevalence rates of C trachomatis in Trinidad are similar to those from Jamaica
Good correlation of in-house and commercial ELISA tests with WHIF test
Urgent need for screening and treatment strategies for C trachomatis in West Indies
Financial support was provided by the University of Sheffield and Bristol Public Health Laboratory.
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