Tools to Support Policy Decisions Related to Treatment Strategies and Surveillance of Schistosomiasis Japonica towards Elimination

Abstract

BackgroundAppropriate diagnostics to monitor disease trends and assess the effectiveness and impact of interventions are essential for guiding treatment strategies at different thresholds of schistosomiasis transmission and for certifying elimination. Field validation of these assays is urgently needed before they can be adopted to support policy decisions of the national programme for control and elimination of schistosomiasis in P.R. China. We compared the efficacy and utility of different immunoassays in guiding control strategies and monitoring the endemic status of S. japonicum infections towards elimination.Methodology/Principal FindingsA cross-sectional survey was conducted in seven villages with different transmission intensities settings to assess the performance and utility of three immunoassays, e.g., an indirect hemagglutination assay (IHA_JX), an enzyme linked immunosorbent assay (ELISA_SZ), and a dot immunogold filtration assay (DIGFA_SH). 6,248 individuals aged 6–65 years old who gave consent and supplied their stool and blood samples were included for data analysis. Results showed that ELISA_SZ performed significantly higher sensitivity (95.45%, 95%CI: 92.94–97.97%) than IHA_JX (87.59%, 95%CI: 83.51–91.49%) and DIGFA_SH (79.55%, 95%CI: 74.68–84.41%), especially in subgroups with very low infection intensity. The specificity of ELISA_SZ, IHA_JX, DIGFA_SH in 6–9 year olds with occasional exposure was nearly 90%. DIGFA_SH performed the highest screening efficacy for patients among three assays with overall positive predicative value of 13.07% (95%CI: 11.42–14.72%). We found a positive correlation of antibody positive rate of IHA_JX with results of stool examination in age strata (r = 0.70, P<0.001). Seropositivity of IHA_JX in children aged 6–9 years old showed an excellent correlation with prevalence of schistosome infection in the seven communities (r = 0.77, P<0.05).Conclusions/SignificanceStudies suggest that ELISA_SZ could be used to guide selective chemotherapy in moderate or low endemic regions. IHA_JX could be used to as a surveillance tool and for certifying elimination of schistosomiasis through monitoring children as a sentinel population.

Prevalence and distribution of <i>Schistosoma haematobium</i> infection among school children living in southwestern shores of Lake Malawi

“…As the prevalence falls further below 10%, improved, easy-to-use tests will be useful to target treatment and monitor prevalence trends and effectiveness of infection control measures. 29,30 Also, there was significant variation in the implementation of control interventions in the study area, despite public health officials doing the work. Monkey Bay Community Hospital provided multifaceted control interventions for infection, unlike the mission facilities (due to limited capacity, support, supervision, and coordination between the mission facilities and the DHO).…”

“…At this lower prevalence, targeted treatment to infected people is more appropriate, given the limited availability of drugs. 29 The facilities therefore need to improve their laboratory services to diagnose schistosomiasis, using simpler tests that do not require specialised skills, training, or equipment-for example, the WHO urine chart or urinalysis reagent stripsbefore treatment initiation. As the prevalence falls further below 10%, improved, easy-to-use tests will be useful to target treatment and monitor prevalence trends and effectiveness of infection control measures.…”

Field Evaluation of a PCR Test for Schistosoma japonicum Egg Detection in Low-Prevalence Regions of China

“…Mean infection intensity was 3.0 EPG (range 0-88). Of the 11 Kato-Katz positive individuals, seven had only 1-3 eggs detected (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). At the village level, S. japonicum infections were detected by Kato-Katz and the hatching test in two of the four villages, and by PCR in three of the four villages (Table 1).…”

“…[5][6][7] The performance of immunoassays such as indirect hemagglutination assay, enzyme-linked immunosorbent assay, and dipstick dye immunoassay has recently been assessed. [8][9][10] These studies have shown that immunoassays have high sensitivities ( 90%) and ease of use when compared with coprological methods, but issues of specificity and the inability of antibody detection methods to distinguish between current and past infections are still of concern. Moreover, the sensitivity of serological testing, like coprological testing, declines as infection intensity decreases.…”

Value of a novel diagnostics of rSP13-ELISA toward schistosomiasis elimination in China

“…Currently, the global schistosomiasis control program has made tremendous progress in terms of reducing the schistosomiasis prevalence and morbidity in many endemic countries, particularly after the London Declaration on Neglected Tropical Diseases. With the goal of the disease elimination, low but persistent levels of schistosomiasis transmission require essential changes in many aspects of elimination approaches [5]. For instance, the new tools of diagnosis and surveillance are urgent to be used in the local settings with low-intensity infections of hosts and in the evaluation of intervention effectiveness.…”