Background The World Health Organization recommends the use of Schisto point-of-care circulating cathodic anti-gens(Schisto POC-CCA)for screening of Schistosoma mansoni as it offers better sensitivity than microscopy....Background The World Health Organization recommends the use of Schisto point-of-care circulating cathodic anti-gens(Schisto POC-CCA)for screening of Schistosoma mansoni as it offers better sensitivity than microscopy.However,there are limitation facing the use of this method including timely availability of the test cassettes.The aim of this study was to determine the reliability of dried urine spot(DUS)method for collection of urine and detection of S.mansoni using Schisto POC-CCA cassettes in a resource-limited settings.Methods A cross-sectional study was conducted between October and November 2022 among 250 primary school children in Sengerema District,northwestern Tanzania.S.mansoni CCA was detected in filter paper-based DUSs,liquid urine using DUS Schisto POC-CCA(index),and direct urine Schisto POC-CCA(comparator)methods respectively.S.mansoni eggs in stool were detected using duplicate Kato-Katz(KK)method.The measures of accuracy were com-puted and compared between the index and comparator methods.The strength of agreement between inter-raters precisions was tested using Cohen's kappa(k).Results This study revealed S.mansoni prevalence rates of 28.8%,54.0%and 50.8%by duplicate KK,direct urine Schisto POC-CCA and DUS Schisto POC-CCA methods respectively.The mean intensity of infection among infected participants Was 86.3 eggs per gram of stool(EPG)ranging from 12.0 EPG to 824.0 EPG.The sensitivity of DUS Schisto POC-CCA and direct urine Schisto POC-CCA Was 94.44%(95%CI:89.15-99.74%)and 97.22%(95%CI:93.43-100.00%)respectively.The DUS Schisto POC-CCA method had slightly higher specificity(66.85%)than direct urine Schisto POC-CCA method(63.48%).The accuracy of the DUS Schisto POC-CCA Was found to be slightly high(74.80%,95%CI:68.94-79.06%)compared to that of direct urine Schisto POC-CCA(73.20%,95%CI:67.25-78.59%).There was good agreement between two laboratory technologists who performed the DUS Schisto POC-CCA method on similar samples(k=0.80,95%CI:0.59-0.95).Conclusions The DUS Schisto POC-CCA method had comparable S.mansoni detection accuracy to direct urine Schisto POC-CCA.This suggests that the method could be a potential alternative to direct urine Schisto POC-CCA for screening S.mansoni in resource-limited situations.展开更多
Mapping and diagnosis of infections by the three major schistosome species(Schistosoma haematobium,S.mansoni and S.japonicum)has been done with assays that are known to be specific but increasingly insensitive as prev...Mapping and diagnosis of infections by the three major schistosome species(Schistosoma haematobium,S.mansoni and S.japonicum)has been done with assays that are known to be specific but increasingly insensitive as prevalence declines or in areas with already low prevalence of infection.This becomes a true challenge to achieving the goal of elimination of schistosomiasis because the multiplicative portion of the life-cycle of schistosomes,in the snail vector,favors continued transmission as long as even a few people maintain low numbers of worms that pass eggs in their excreta.New mapping tools based on detection of worm antigens(circulating cathodic antigen-CCA;circulating anodic antigen-CAA)in urine of those infected are highly sensitive and the CAA assay is reported to be highly specific.Using these tools in areas of low prevalence of all three of these species of schistosomes has demonstrated that more people harbor adult worms than are regularly excreting eggs at a level detectable by the usual stool assay(Kato-Katz)or by urine filtration.In very low prevalence areas this is sometimes 6-to10-fold more.Faced with what appears to be a sizable population of“egg-negative/worm-positive schistosomiasis”especially in areas of very low prevalence,national NTD programs are confounded about what guidelines and strategies they should enact if they are to proceed toward a goal of elimination.There is a critical need for continued evaluation of the assays involved and to understand the contribution of this“egg-negative/worm-positive schistosomiasis”condition to both individual morbidity and community transmission.There is also a critical need for new guidelines based on the use of these more sensitive assays for those national NTD programs that wish to move forward to strategies designed for elimination.展开更多
Background:Given the restricted distribution of Schistosoma mekongi in one province in Lao People’s Democratic Republic(Lao PDR)and two provinces in Cambodia,together with progress of the national control programmes ...Background:Given the restricted distribution of Schistosoma mekongi in one province in Lao People’s Democratic Republic(Lao PDR)and two provinces in Cambodia,together with progress of the national control programmes aimed at reducing morbidity and infection prevalence,the elimination of schistosomiasis mekongi seems feasible.However,sensitive diagnostic tools will be required to determine whether elimination has been achieved.We compared several standard and novel diagnostic tools in S.mekongi-endemic areas.Methods:The prevalence and infection intensity of S.mekongi were evaluated in 377 study participants from four villages in the endemic areas in Lao PDR and Cambodia using Kato-Katz stool examination,antibody detection based on an enzyme-linked immunosorbent assay(ELISA)and schistosome circulating antigen detection by lateral-flow tests.Two highly sensitive test systems for the detection of cathodic and anodic circulating antigens(CCA,CAA)in urine and serum were utilized.Results:Stool microscopy revealed an overall prevalence of S.mekongi of 6.4%(one case in Cambodia and 23 cases in Lao PDR),while that of Opisthorchis viverrini,hookworm,Trichuris trichiura,Ascaris lumbricoides and Taenia spp.were 50.4%,28.1%,3.5%,0.3%and 1.9%,respectively.In the urine samples,the tests for CCA and CAA detected S.mekongi infections in 21.0%and 38.7%of the study participants,respectively.In the serum samples,the CAA assay revealed a prevalence of 32.4%,while a combination of the CAA assay in serum and in urine revealed a prevalence of 43.2%.There was a difference between the two study locations with a higher prevalence reached in the samples from Lao PDR.Conclusions:The CCA,CAA and ELISA results showed substantially higher prevalence estimates for S.mekongi compared to Kato-Katz thick smears.Active schistosomiasis mekongi in Lao PDR and Cambodia might thus have been considerably underestimated previously.Hence,sustained control efforts are still needed to break transmission of S.mekongi.The pivotal role of highly sensitive diagnostic assays in areas targeting elimination cannot be overemphasised.展开更多
Background:Schistosomiasis and soil-transmitted helminths(STHs)contribute high disease burdens amongst the neglected tropical diseases(NTDs)and are public health problems in Angola.This study reports the prevalence,in...Background:Schistosomiasis and soil-transmitted helminths(STHs)contribute high disease burdens amongst the neglected tropical diseases(NTDs)and are public health problems in Angola.This study reports the prevalence,intensity and risk factors for schistosomiasis and STH infection in Huambo,Uige and Zaire provinces,Angola,to inform a school-based preventive chemotherapy program.Methods:A two-stage cluster design was used to select schools and schoolchildren to participate in parasitological and water,sanitation and hygiene(WASH)surveys across Huambo,Uige,and Zaire provinces.Point-of-care circulating cathodic antigen and urinalysis rapid diagnostic tests(RDTs)were used to determine the prevalence of Schistosoma mansoni and S.haematobium,respectively.Kato-Katz was used to identify and quantify STH species and quantify and compare with RDTs for S.mansoni.Urine filtration was used to quantify and compare with RDTs for S.haematobium.Descriptive statistics were used for prevalence and infection intensity of schistosomiasis and STH infection.Performance of RDTs was assessed through specificity and Cohen’s Kappa agreement with microscopy.A multivariate regression analysis was used to determine demographic and WASH factors associated with schistosomiasis and STH infection.Results:A total 575 schools and 17,093 schoolchildren participated in the schistosomiasis survey,of which 121 schools and 3649 schoolchildren participated in the STH survey.Overall prevalence of S.mansoni was 21.2%(municipality range 0.9–74.8%)and S.haematobium 13.6%(range 0–31.2%),with an overall prevalence of schistosomiasis of 31.4%(range 5.9–77.3%).Overall prevalence of Ascaris lumbricoides was 25.1%(range 0–89.7%),hookworm 5.2%(range 0–42.6%),and Trichuris trichiura 3.6%(range 0–24.2%),with an overall prevalence of STH infection of 29.5%(range 0.8–89.7%).Ecological zone and ethnicity were factors associated with schistosomiasis and STH infection,with older age and female sex additional risk factors for S.haematobium.Conclusions:Most municipalities met World Health Organization defined prevalence thresholds for a schistosomiasis preventive chemotherapy program.A STH preventive chemotherapy program is indicated for nearly all municipalities in Uige and select municipalities in Huambo and Zaire.The association between ecological zone and ethnicity with schistosomiasis and STH infection necessitates further evaluation of home and school environmental,sociodemographic and behavioural factors to inform targeted control strategies to complement preventive chemotherapy programs.展开更多
文摘Background The World Health Organization recommends the use of Schisto point-of-care circulating cathodic anti-gens(Schisto POC-CCA)for screening of Schistosoma mansoni as it offers better sensitivity than microscopy.However,there are limitation facing the use of this method including timely availability of the test cassettes.The aim of this study was to determine the reliability of dried urine spot(DUS)method for collection of urine and detection of S.mansoni using Schisto POC-CCA cassettes in a resource-limited settings.Methods A cross-sectional study was conducted between October and November 2022 among 250 primary school children in Sengerema District,northwestern Tanzania.S.mansoni CCA was detected in filter paper-based DUSs,liquid urine using DUS Schisto POC-CCA(index),and direct urine Schisto POC-CCA(comparator)methods respectively.S.mansoni eggs in stool were detected using duplicate Kato-Katz(KK)method.The measures of accuracy were com-puted and compared between the index and comparator methods.The strength of agreement between inter-raters precisions was tested using Cohen's kappa(k).Results This study revealed S.mansoni prevalence rates of 28.8%,54.0%and 50.8%by duplicate KK,direct urine Schisto POC-CCA and DUS Schisto POC-CCA methods respectively.The mean intensity of infection among infected participants Was 86.3 eggs per gram of stool(EPG)ranging from 12.0 EPG to 824.0 EPG.The sensitivity of DUS Schisto POC-CCA and direct urine Schisto POC-CCA Was 94.44%(95%CI:89.15-99.74%)and 97.22%(95%CI:93.43-100.00%)respectively.The DUS Schisto POC-CCA method had slightly higher specificity(66.85%)than direct urine Schisto POC-CCA method(63.48%).The accuracy of the DUS Schisto POC-CCA Was found to be slightly high(74.80%,95%CI:68.94-79.06%)compared to that of direct urine Schisto POC-CCA(73.20%,95%CI:67.25-78.59%).There was good agreement between two laboratory technologists who performed the DUS Schisto POC-CCA method on similar samples(k=0.80,95%CI:0.59-0.95).Conclusions The DUS Schisto POC-CCA method had comparable S.mansoni detection accuracy to direct urine Schisto POC-CCA.This suggests that the method could be a potential alternative to direct urine Schisto POC-CCA for screening S.mansoni in resource-limited situations.
基金The authors received financial support from the University of Georgia Research Foundation,Inc.,which was funded by the Bill&Melinda Gates Foundation for the SCORE projectThe funders had no role in the study design,data collection and analysis,decision to publish or preparation of the manuscript.
文摘Mapping and diagnosis of infections by the three major schistosome species(Schistosoma haematobium,S.mansoni and S.japonicum)has been done with assays that are known to be specific but increasingly insensitive as prevalence declines or in areas with already low prevalence of infection.This becomes a true challenge to achieving the goal of elimination of schistosomiasis because the multiplicative portion of the life-cycle of schistosomes,in the snail vector,favors continued transmission as long as even a few people maintain low numbers of worms that pass eggs in their excreta.New mapping tools based on detection of worm antigens(circulating cathodic antigen-CCA;circulating anodic antigen-CAA)in urine of those infected are highly sensitive and the CAA assay is reported to be highly specific.Using these tools in areas of low prevalence of all three of these species of schistosomes has demonstrated that more people harbor adult worms than are regularly excreting eggs at a level detectable by the usual stool assay(Kato-Katz)or by urine filtration.In very low prevalence areas this is sometimes 6-to10-fold more.Faced with what appears to be a sizable population of“egg-negative/worm-positive schistosomiasis”especially in areas of very low prevalence,national NTD programs are confounded about what guidelines and strategies they should enact if they are to proceed toward a goal of elimination.There is a critical need for continued evaluation of the assays involved and to understand the contribution of this“egg-negative/worm-positive schistosomiasis”condition to both individual morbidity and community transmission.There is also a critical need for new guidelines based on the use of these more sensitive assays for those national NTD programs that wish to move forward to strategies designed for elimination.
基金We are grateful to financial support of the Task Force for Global Health,Neglected Tropical Diseases Support Centre,the Department of Parasitology,Leiden University Medical Center and the Swiss Tropical and Public Health Institute.
文摘Background:Given the restricted distribution of Schistosoma mekongi in one province in Lao People’s Democratic Republic(Lao PDR)and two provinces in Cambodia,together with progress of the national control programmes aimed at reducing morbidity and infection prevalence,the elimination of schistosomiasis mekongi seems feasible.However,sensitive diagnostic tools will be required to determine whether elimination has been achieved.We compared several standard and novel diagnostic tools in S.mekongi-endemic areas.Methods:The prevalence and infection intensity of S.mekongi were evaluated in 377 study participants from four villages in the endemic areas in Lao PDR and Cambodia using Kato-Katz stool examination,antibody detection based on an enzyme-linked immunosorbent assay(ELISA)and schistosome circulating antigen detection by lateral-flow tests.Two highly sensitive test systems for the detection of cathodic and anodic circulating antigens(CCA,CAA)in urine and serum were utilized.Results:Stool microscopy revealed an overall prevalence of S.mekongi of 6.4%(one case in Cambodia and 23 cases in Lao PDR),while that of Opisthorchis viverrini,hookworm,Trichuris trichiura,Ascaris lumbricoides and Taenia spp.were 50.4%,28.1%,3.5%,0.3%and 1.9%,respectively.In the urine samples,the tests for CCA and CAA detected S.mekongi infections in 21.0%and 38.7%of the study participants,respectively.In the serum samples,the CAA assay revealed a prevalence of 32.4%,while a combination of the CAA assay in serum and in urine revealed a prevalence of 43.2%.There was a difference between the two study locations with a higher prevalence reached in the samples from Lao PDR.Conclusions:The CCA,CAA and ELISA results showed substantially higher prevalence estimates for S.mekongi compared to Kato-Katz thick smears.Active schistosomiasis mekongi in Lao PDR and Cambodia might thus have been considerably underestimated previously.Hence,sustained control efforts are still needed to break transmission of S.mekongi.The pivotal role of highly sensitive diagnostic assays in areas targeting elimination cannot be overemphasised.
文摘Background:Schistosomiasis and soil-transmitted helminths(STHs)contribute high disease burdens amongst the neglected tropical diseases(NTDs)and are public health problems in Angola.This study reports the prevalence,intensity and risk factors for schistosomiasis and STH infection in Huambo,Uige and Zaire provinces,Angola,to inform a school-based preventive chemotherapy program.Methods:A two-stage cluster design was used to select schools and schoolchildren to participate in parasitological and water,sanitation and hygiene(WASH)surveys across Huambo,Uige,and Zaire provinces.Point-of-care circulating cathodic antigen and urinalysis rapid diagnostic tests(RDTs)were used to determine the prevalence of Schistosoma mansoni and S.haematobium,respectively.Kato-Katz was used to identify and quantify STH species and quantify and compare with RDTs for S.mansoni.Urine filtration was used to quantify and compare with RDTs for S.haematobium.Descriptive statistics were used for prevalence and infection intensity of schistosomiasis and STH infection.Performance of RDTs was assessed through specificity and Cohen’s Kappa agreement with microscopy.A multivariate regression analysis was used to determine demographic and WASH factors associated with schistosomiasis and STH infection.Results:A total 575 schools and 17,093 schoolchildren participated in the schistosomiasis survey,of which 121 schools and 3649 schoolchildren participated in the STH survey.Overall prevalence of S.mansoni was 21.2%(municipality range 0.9–74.8%)and S.haematobium 13.6%(range 0–31.2%),with an overall prevalence of schistosomiasis of 31.4%(range 5.9–77.3%).Overall prevalence of Ascaris lumbricoides was 25.1%(range 0–89.7%),hookworm 5.2%(range 0–42.6%),and Trichuris trichiura 3.6%(range 0–24.2%),with an overall prevalence of STH infection of 29.5%(range 0.8–89.7%).Ecological zone and ethnicity were factors associated with schistosomiasis and STH infection,with older age and female sex additional risk factors for S.haematobium.Conclusions:Most municipalities met World Health Organization defined prevalence thresholds for a schistosomiasis preventive chemotherapy program.A STH preventive chemotherapy program is indicated for nearly all municipalities in Uige and select municipalities in Huambo and Zaire.The association between ecological zone and ethnicity with schistosomiasis and STH infection necessitates further evaluation of home and school environmental,sociodemographic and behavioural factors to inform targeted control strategies to complement preventive chemotherapy programs.
