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Researchers in Ethiopia's Amhara region successfully implemented rapid lateral flow assay (LFA) blood tests to detect antibodies against Chlamydia trachomatis, the bacterium causing trachoma, processing 2,542 dried blood spot samples over 12 days. The testing revealed 20.8% seroprevalence in children aged 1-5 years and 85.8% in adults over 15, with results aligning well with clinical examinations showing 28.6% active trachoma and 5.7% current infections in young children. This demonstrates that regional public health laboratories can effectively use rapid blood tests alongside traditional methods to monitor trachoma transmission and guide elimination efforts.
Why it matters
This proof-of-concept shows that resource-limited settings can integrate modern serological surveillance into existing public health infrastructure without requiring specialized external facilities. The approach provides a scalable, practical tool for Ethiopia and similar countries to track progress toward eliminating trachoma as a public health problem, enabling data-driven decisions about where to intensify interventions.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Trachoma programs are increasingly using serological tools to complement clinical indicators and to measure current and historical transmission of Chlamydia trachomatis (Ct). In January 2024, the Amhara Trachoma Program in Ethiopia implemented the Pgp3 lateral flow assay (LFA) for trachoma serosurveillance through the regional public health laboratory system. Three Amhara Public Health Institute Trachoma Molecular Laboratory scientists were trained and passed competency testing on the assay. The scientists then conducted LFA testing on dried blood spot (DBS) samples collected during a December 2023 trachoma impact survey in Tach Gaynt, Amhara. During testing, 2,542 DBS samples were processed over 12 days. Age-specific seroprevalence and seroconversion rates (SCRs) were estimated. Among children ages 1-5 years, seroprevalence was 20.8% (95% confidence interval [CI]): 17.4-24.7%), and the SCR was 7.9 per 100 child-years (95% CI: 4.6-13.5). Among children ages 1-9 years, seroprevalence was 26.0% (95% CI: 22.9-29.3%), and the SCR was 7.0 per 100 child-years (95% CI: 4.6-10.6). Seroprevalence among individuals ages 15 years and older was 85.8% (95% CI: 83.9-87.4%). Trachomatous inflammation-follicular prevalence among children ages 1-9 years (TF1-9) was 28.6% (95% CI: 22.1-35.4%), and Ct infection among children ages 1-5 years was 5.7%, suggesting ongoing transmission. The concordance between LFA results, TF1-9 prevalence, and Ct infection prevalence supports the utility of the LFA for trachoma surveillance in Ethiopia, with Pgp3 LFA testing performed in a regional public health laboratory. Integrating LFA-based serology into the Ethiopia national trachoma surveillance systems offers a scalable approach to guide programmatic decisions and support trachoma elimination as a public health problem.