Table 1.
Three use-cases and their accompanying target product profiles for diagnostics in soil-transmitted helminth control programs.
This Table is based on a framework described by Lim and colleagues [11]. The Table provides a brief overview of the target product profiles (TPPs) for three out of the 4 described use-cases (#1–3) defined for soil-transmitted helminth (STH) preventive chemotherapy (PC) programs.
Table 2.
Fecal egg count thresholds defining low, moderate and heavy infection intensity [23].
The fecal egg counts are expressed as eggs per gram of stool.
Fig 1.
Number of subjects withheld at recruitment, baseline and follow-up, and for the statistical data analysis.
STH: soil-transmitted helminth; n: number of subjects; FECs: fecal egg counts expressed in eggs per gram of stool (EPG), 2x KK: duplicate Kato-Katz.
Table 3.
The overall clinical sensitivity of five diagnostic methods for soil-transmitted helminth infections in stool.
The Table summarizes the clinical sensitivity and corresponding 95% confidence intervals [95% CI] of Kato-Katz (single and duplicate), Mini-FLOTAC, FECPAKG2 and qPCR across all cases of Ascaris (n = 540), Trichuris (n = 889) and hookworms (n = 675). In addition, it reports the level of significance (p-value) for the hypothesis that the clinical sensitivity is different from that of a single Kato-Katz.
Fig 2.
Clinical sensitivity of five diagnostic methods as a function of egg excretion.
The bar plots represent the clinical sensitivity of single Kato-Katz (blue), qPCR (white), duplicate Kato-Katz (grey), Mini-FLOTAC (black) and FECPAKG2 (red) across seven infection intensity categories. The range in fecal egg counts (FECs; expressed as eggs per gram of stool (EPG)) is shown on the X-axis. These FECs correspond with the highest FECs across the microscopic methods (Kato-Katz, Mini-FLOTAC and FECPAKG2). The Y-axis represent the clinical sensitivity in percentage. The number samples for each infection category (n) is shown above the bars. The WHO defined classes of infections intensities (low (L), moderate (M) and high (H)) are shown on top. The dotted horizontal line represents a clinical sensitivity of 95%.
Table 4.
The clinical sensitivity of five diagnostic methods for low infection intensity STH infections.
The Table summarizes the clinical sensitivity and corresponding 95% confidence intervals [95% CI] of Kato-Katz (single and duplicate), Mini-FLOTAC, FECPAKG2 and qPCR across low intensity infections of Ascaris (n = 340), Trichuris (n = 519) and hookworms (n = 602). In addition, it reports the level of significance (p-value) for the hypothesis that the clinical sensitivity is different from that of a single Kato-Katz.
Fig 3.
Agreement in fecal egg counts by the four microscopic methods.
The scatterplots illustrate the agreement in fecal egg counts (FECs, expressed in eggs per gram of stool (EPG) based on a single Kato-Katz (1x KK) with those obtained with a duplicate Kato-Katz (grey dots), Mini-FLOTAC (black dots) and FECPAKG2 (red dots) for A. lumbricoides (n = 540), T. trichiura (n = 889) and hookworm (n = 675). In each panel, the Spearman’s correlation coefficient (Rs) is given. The striped diagonal line represents the line of equivalence.
Table 5.
The mean fecal soil-transmitted helminth egg counts based on four microscopic methods.
The arithmetic mean of fecal egg counts (FECs; expressed as eggs per gram of stool) were calculated for each of the four microscopic methods (Kato-Katz (single and duplicate), Mini-FLOTAC and FECPAKG2).
Fig 4.
Agreement in infection intensity classification by four microscopic method.
Each bar represents all cases classified by a single Kato-Katz (1x KK; reference method) into low, moderate or heavy infection intensity using the WHO threshold criteria (Table 2). The Y-axis of each bar represents the proportion of these cases that are categorized as low, moderate and heavy intensity infections by means of a duplicate Kato-Katz (2x KK; top row plots), Mini-FLOTAC (middle row plots) and FECPAKG2 (bottom row plots). The white color indicates cases classified as low infection intensity, grey indicates cases classified as moderate infection intensity and black indicates cases categorized as heavy infection intensity, by either duplicate Kato-Katz, Mini-FLOTAC or FECPAKG2. There is a full agreement in classifying the intensity of infection with the reference method when the bars representing low, moderate and high infection intensities by the reference method are completely white, grey and black, respectively. As an example, of all heavy intensity hookworm infections, only approximately 20% are classified correctly as heavy when using the FECPAKG2, and approximately 60% and 20% are misclassified as low and moderate, respectively.
Fig 5.
Agreement in fecal egg counts by Kato-Katz and genomic concentration by qPCR.
The scatterplots illustrate the agreement in fecal egg counts (FECs; expressed in eggs per gram of stool (EPG)) based on a single Kato-Katz and the DNA concentration (expressed in number of genome equivalents per ml (GE/ml)) based on qPCR for Ascaris (n = 540), Trichuris (n = 889) and hookworm (n = 675). In each panel, the Spearman’s correlation coefficient (RS) is shown.