The prevalence of trachoma, ocular Chlamydia trachomatis infection and anti-Pgp3 antibodies in Choiseul Province, Solomon Islands

Trachoma, caused by repeated ocular infection with Chlamydia trachomatis, remains a leading infectious cause of blindness globally, with significant implications for public health. The World Health Organization and partners aim to eliminate trachoma as a public health problem by 2030, targeting specific prevalence thresholds for trachomatous trichiasis (TT) and trachomatous inflammation-follicular (TF). Diagnosis is primarily clinical. Studies have shown discrepancies between prevalence estimates of TF and C. trachomatis infection. This study, undertaken in Choiseul, Solomon Islands, evaluated TF, evidence of current C. trachomatis infection (by polymerase chain reaction (PCR) on conjunctival swabs), and evidence of past exposure to that bacterium (using anti-Pgp3 serology on dried blood spots). Among 645 1-9-year-old children, TF prevalence was 17.5% and C. trachomatis prevalence was 8.5%. These findings suggest transmission of sufficient intensity to pose a public health problem. Notably, 59% of children with TF had evidence of neither current nor previous C. trachomatis infection. Increasing age was associated with TF and evidence of past infection, but not current infection. The community had poor water, sanitation, and hygiene conditions. This study highlights the benefit of integrating laboratory testing for guiding effective trachoma elimination as a public health problem. Although our work was limited by imperfect enrolment of resident children and the logistical challenges of collecting samples in a remote region, we believe our data justify continued public health interventions against trachoma in Choiseul.