Table 1 Summary of the trachoma indicators, methodology, and sample size
Trachoma indicator | Methodology | Sample size (children aged 0–9 years) | Total | |||
|---|---|---|---|---|---|---|
The Gambia | Senegal | |||||
Baseline (March–May 2006) | One year follow-up (June–July 2007) | Baseline (January–February 2007) | One year follow-up (March–May 2008) | |||
Children aged 0–9 years examined for active trachoma (TF and/or TI) | WHO simplified grading system [27] | 1171 | 1171 | 1613 | 1771 | 5726 |
Ocular C. trachomatis infection | Amplicor PCR (Roche Molecular Systems) | 1171 | 1171 | 1613 | 1771 | 5726 |
Organism load of Amplicor-positives | ompA copy number estimates using two real-time quantitative PCR assays for genovars A and B separately [29] | 35 | 45 | 29 | 64 | 173 |
Multi-locus sequence typing (MLST) | Determination of sequences at the five loci: hctB, CT058, CT144, CT172, pbpB [22, 23] | 13 | 18 | 13 | 29 | 73 |
ompA sequencing | Sequences aligned against reference sequences from A/HAR 13 (NC_007429, genovar A) and B/Jali20/OT (NC_012686, genovar B), with alignments trimmed at the ends until high quality (Q20) base-calls were present at all positions | 19 | 21 | 16 | 38 | 94 |
MLST6 | The five MLST regions combined with ompA | 14 | 18 | 12 | 28 | 72 |
Whole-genome sequencing (WGS) | Set of 71 WGS from the Bijagos Islands with inferred MLST and ompA types [40] | na | na | na | na | 71 |