| 2 | GPS-based fine-scale mapping surveys for schistosomiasis assessment: a practical introduction and documentation of field implementation显示文摘Background Fine-scale mapping of schistosomiasis to guide micro-targeting of interventions will gain importance in elimination settings,where the heterogeneity of transmission is often pronounced.Novel mobile applications offer new opportunities for disease mapping.We provide a practical introduction and documentation of the strengths and shortcomings of GPS-based household identification and participant recruitment using tablet-based applications for fine-scale schistosomiasis mapping at sub-district level in a remote area in Pemba,Tanzania.Methods A community-based household survey for urogenital schistosomiasis assessment was conducted from November 2020 until February 2021 in 20 small administrative areas in Pemba.For the survey,1400 housing structures were prospectively and randomly selected from shapefile data.To identify pre-selected structures and collect survey-related data,field enumerators searched for the houses’geolocation using the mobile applications Open Data Kit(ODK)and MAPS.ME.The number of inhabited and uninhabited structures,the median distance between the pre-selected and recorded locations,and the dropout rates due to non-participation or non-submission of urine samples of sufficient volume for schistosomiasis testing was assessed.Results Among the 1400 randomly selected housing structures,1396(99.7%)were identified by the enumerators.The median distance between the pre-selected and recorded structures was 5.4 m.A total of 1098(78.7%)were residential houses.Among them,99(9.0%)were dropped due to continuous absence of residents and 40(3.6%)households refused to participate.In 797(83.1%)among the 959 participating households,all eligible household members or all but one provided a urine sample of sufficient volume.Conclusions The fine-scale mapping approach using a combination of ODK and an offline navigation application installed on tablet computers allows a very precise identification of housing structures.Dropouts due to non-residential housing structures,absence,non-participation and lack of urine need to be considered in survey designs.Our findings can guide the planning and implementation of future household-based mapping or longitudinal surveys and thus support micro-targeting and follow-up of interventions for schistosomiasis control and elimination in remote areas. | Lydia Trippler Mohammed Nassor Ali Shaali Makame Ame Said Mohammed Ali Fatma Kabole Jan Hattendorf Stefanie Knopp | 2022 | Infectious Diseases of Poverty2022，11，1： | 0 |
| 3 | Performance of a real-time PCR approach for diagnosing Schistosoma haematobium infections of different intensity in urine samples from Zanzibar显示文摘Background:Efforts to control and eliminate schistosomiasis have accelerated over the past decade.As parasite burden,associated morbidity and egg excretion decrease,diagnosis with standard parasitological methods becomes harder.We assessed the robustness and performance of a real-time PCR(qPCR)approach in comparison with urine filtration microscopy and reagent strip testing for the diagnosis of Schistosoma haematobium infections of different intensities.Methods:The robustness of DNA isolation and qPCR was validated in eight laboratories from Europe and Africa.Subsequently,792 urine samples collected during cross-sectional surveys of the Zanzibar Elimination of Schistosomiasis Transmission(ZEST)project in 2012-2017 were examined with qPCR in 2018.Diagnostic sensitivity of the qPCR was calculated at different infection intensity categories,using urine filtration microscopy as reference test.Spearman's rank correlation between Ct-values and S.haematobium egg counts was assessed and Ct-value percentiles for infection intensity categories determined.Results:S.haematobium Dra1 DNA-positive samples were identified correctly in all eight laboratories.Examination of urine samples from Zanzibar revealed Dra1 DNA in 26.8%(212/792)by qPCR,S.haematobium eggs in 13.3%(105/792)by urine filtration,and microhaematuria in 13.8%(109/792)by reagent strips.Sensitivity of the qPCR increased with augmenting egg counts:80.6%(29/36)for counts between 1 and 4 eggs,83.3%(15/18)for counts between 5 and 9 eggs,100%(23/23)for counts between 10 and 49 eggs,and 96.4%(27/28)for counts of 50+eggs.There was a significant negative correlation between Ct-values and egg counts(Spearman's rho=-0.49,P<0.001).Seventy-five percent of the Ct-values were≥33 in the egg-negative category,<31 in the light intensity category,and<24 in the heavy intensity category.Conclusions:While the sensitiivity of the qPCR was^80%for very light intensity infections(egg counts<10),in general,the Dra1 based qPCR assay detected twice as many S.haematobium infections compared with classical parasitological tests.The qPCR is hence a sensitive,urine-based approach for S.haernatcbium diagnosis that can be used for impact assessment of schistosomiasis elimination programmes,individual diagnosis,and in improved format also for verification and certification of elimination.Trial registration:ISRCTN,ISRCTN48837681.Registered 05 September 2012-Retrospectively registered. | Dominique Keller Julian Rothen Jean-Pierre Dangy Corina Saner Claudia Daubenberger Fiona Allan Shaali M.Ame Said M.Ali Fatma Kabole Jan Hattendorf David Rollinson Ralf Seyfarth Stefanie Knopp | 2020 | Infectious Diseases of Poverty2020，9，5： | 0 |
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