Evaluation of a PGP 3 ELISA for surveillance of the burden of Chlamydia 1 infection in women from Australia and Samoa 2 3 4

47 Serological assays can be used to investigate the population burden of infection and 48 potentially sequelae from Chlamydia. We investigated the PGP3 ELISA as a sero49 epidemiological tool for infection or sub-fertility in Australian and Samoan women. 50 The PGP3 ELISA absorbance levels were compared between groups of women with 51 infertility, fertile, and current chlamydial infections. In the Australian groups, women 52 with chlamydial tubal factor infertility had significantly higher absorbance levels in the 53 PGP3 ELISA compared to fertile women (p<0.0001), but not when compared to 54 women with current chlamydial infection (p=0.44). In the Samoan study, where the 55 prevalence of chlamydial infections is much higher there were significant differences 56 in the PGP3 ELISA absorbance levels between chlamydial sub-fertile women and 57 fertile women (p=0.003). There was no difference between chlamydial sub-fertile 58 women and women with a current infection (p=0.829). The results support that the 59 PGP3 assay is effective for sero-epidemiological analysis of burden of infection, but 60 not for evaluation of chlamydial pathological sequelae such as infertility. 61 62 63