Rationale for Quality Assurance in Fecal Egg Monitoring of Soil-Transmitted Helminthiasis

Abstract

Abstract. Substantial investment has been made into the once "neglected" tropical disease, soil-transmitted helminthiasis, and into control programs that operate within a framework of mapping baseline disease distribution, measuring the effectiveness of applied interventions, establishing when to cease drug administration, and for posttreatment evaluations. However, critical to each of these stages is the determination of helminth infection. The limitations of traditional microscope-based fecal egg diagnostics have not provided quality assurance in the monitoring of parasite disease and suboptimal treatment regimes provide for the potential development of parasite resistance to anthelmintic drugs. Improved diagnostic and surveillance tools are required to protect therapeutic effectiveness and to maintain funder confidence. Such tools may be on the horizon with emergent technologies that offer potential for enhanced visualization and quality-assured quantitation of helminth eggs.

Efficacy and safety of praziquantel and dihydroartemisinin piperaquine combination for treatment and control of intestinal schistosomiasis: A randomized, non-inferiority clinical trial

“…soil-transmitted helminths), which is time-dependent (within 1 hour of smear preparation) was not in the scope of this study. Another independent technician re-examined 10% of the slides from both positive and negative results for quality assurance [ 40 , 41 ].…”

Identifying thresholds for classifying moderate-to-heavy soil-transmitted helminth intensity infections for FECPAKG2, McMaster, Mini-FLOTAC and qPCR

“…Each of these methods have important advantages and disadvantages over the Kato-Katz. Important advantages are a clearer microscopic view (FECPAK G2 , McMaster and (Mini-)FLOTAC) [ 14 – 16 ], a higher clinical sensitivity (= proportion of diseased individuals correctly diagnosed as infected; (Mini-)FLOTAC and qPCR) [ 17 – 19 ], opportunities for automated egg counting and quality control (FECPAK G2 ) [ 20 ], and the abilities to differentiate hookworm species and to simultaneously detect parasites other than STHs (qPCR) [ 21 – 23 ]. Chief limitations of these novel methods are the need for well-equipped laboratories with well-trained technicians (FLOTAC; qPCR), and the higher cost of processing large numbers of samples (FECPAK G2 ; McMaster, Mini-FLOTAC and qPCR).…”

Therapeutic efficacy of albendazole against soil-transmitted helminthiasis in children measured by five diagnostic methods

“…Recently, novel methods have been introduced in the field of STH diagnostics, including Mini-FLOTAC [14, 15], FECPAK G2 [16, 17] and the DNA-based diagnostic methods such as quantitative PCR (qPCR) [18–20]. Each of these methods offers one or more advantages over the recommended methods, pertaining to increased clinical sensitivity [15, 18, 21–23] and specificity (qPCR is able to differentiate different helminths at the species level) [24–27], quality assurance (FECPAK G2 automatically stores images of each sample which can be consulted at any time [17, 28]; qPCR includes internal controls within each run [29]), flexibility as to when samples are examined (for both Mini-FLOTAC and qPCR, stool can be preserved for analysis at a later time point [23, 25, 30–32]). Although each of these novel methods has recently been used to evaluate drug efficacy [16, 33, 34], there remains a paucity of studies that perform a head-to-head comparison of the drug efficacy obtained by different diagnostic methods.…”