FioSchisto's expert perspective on implementing WHO guidelines for schistosomiasis control and transmission elimination in Brazil.

The World Health Organization (WHO) recognizes schistosomiasis as one of the Neglected Tropical Diseases targeted for global elimination in the 2030 Agenda of the Sustainable Development Goals. In Brazil, schistosomiasis mansoni is considered a public health problem, particularly prevalent among vulnerable populations living in areas with poor environmental and sanitary conditions. In 2022, the WHO published a Guideline encompassing recommendations to assist national programs in endemic countries in achieving morbidity control, eliminating schistosomiasis as a public health problem, and advancing towards interrupting transmission. The perspectives presented here, collectively prepared by members of the Oswaldo Cruz Foundation's (Fiocruz) Schistosomiasis Translational Program (FioSchisto), along with invited experts, examine the feasibility of the WHO recommendations for the Brazilian settings, providing appropriate recommendations for public health policies applicable to the epidemiological reality of Brazil, and suggests future research to address relevant issues. In Brazil, the provision of safe water and sanitation should be the key action to achieve schistosomiasis elimination goals. The agencies involved in measures implementation should act together with the Primary Care teams for planning, executing, monitoring, and evaluating actions in priority municipalities based on their epidemiological indicators. Host snails control should prioritize judicious ecological interventions at breeding sites. The Information, Education, and Communication (IEC) strategy should be associated with water and sanitation and other control actions, actively involving school community. To identify infected carriers, FioSchisto recommends a two-stage approach of immunological and molecular tests to verify transmission interruption during the intervention and beyond. Praziquantel administration should be done under medical supervision at the Primary Care level. MDA should be considered in exceptional settings, as a measure of initial attack strategy in locations presenting high endemicity, always integrated with water and sanitation, IEC, and snail control. To assist decision-making, as well as the monitoring and evaluation of strategic actions, there is a need for an Information System. FioSchisto considers this systematization essential to make investments in strategic research to support the improvement of schistosomiasis control actions. Efforts toward schistosomiasis elimination in Brazil will succeed with a paradigm shift from the vertical prescriptive framework to a community-centered approach involving intersectoral and interdisciplinary collaboration.

Corrigendum: Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis.

[This corrects the article DOI: 10.3389/fmicb.2022.1048457.].

Accuracy of the urine point-of-care circulating cathodic antigen assay for diagnosing Schistosomiasis mansoni infection in Brazil: A multicenter study.

BACKGROUND: The World Health Organization recommends a market-ready, urine-based point-of-care diagnostic test for circulating cathodic antigens (CCA) to determine the prevalence of S. mansoni. This study evaluated the performance of the URINE CCA (SCHISTO) ECO TESTE® (POC-ECO), which is currently available in Brazil. METHODS: Residents from eight sites with different prevalence estimates provided one urine sample for POC-ECO and one stool sample for Kato-Katz (KK) and Helmintex® (HTX) testing as an egg-detecting reference for infection status. RESULTS: None of the study sites had significantly higher POC-ECO accuracy than KK. CONCLUSIONS: POC-ECO is not currently recommended in Brazilian schistosomiasis elimination programs.

Accuracy of the urine point-of-care circulating cathodic antigen assay for diagnosing Schistosomiasis mansoni infection in Brazil: A multicenter study

ABSTRACT Background: The World Health Organization recommends a market-ready, urine-based point-of-care diagnostic test for circulating cathodic antigens (CCA) to determine the prevalence of S. mansoni. This study evaluated the performance of the URINE CCA (SCHISTO) ECO TESTE® (POC-ECO), which is currently available in Brazil. Methods: Residents from eight sites with different prevalence estimates provided one urine sample for POC-ECO and one stool sample for Kato-Katz (KK) and Helmintex® (HTX) testing as an egg-detecting reference for infection status. Results: None of the study sites had significantly higher POC-ECO accuracy than KK. Conclusions: POC-ECO is not currently recommended in Brazilian schistosomiasis elimination programs.

Teachers as multipliers of knowledge about schistosomiasis: a possible approach for health education programmes.

BACKGROUND: In the past decade, Brazil has significantly reduced the prevalence of schistosomiasis through a combined effort of early treatment of infected people, expansion of basic sanitation infrastructure and educational measures. Despite these efforts, in some areas, prevalence of schistosomiasis exceeds 20% of the school population, who lack knowledge of the risks of the disease. Action can be taken in schools to empower this population about their health condition. This paper describes the role of the teacher as a multiplier of knowledge about schistosomiasis and proposes two different approaches to training these teachers. METHODS: This study used mixed methods to evaluate training of teachers and educational intervention with those teachers' pupils. Two training courses, each with 40 h of face-to-face activity, were offered to 19 teachers, using two different but complementary approaches, based on theoretical references and specific educational strategies: Critical Pedagogical Approach (Training Course I, held in 2013) and Creative Play Approach (Training Course II, held in 2014).The courses included classroom activities, laboratory and field work. After the training, the teachers conducted activities on schistosomiasis with their pupils. These activities involved constructing educational materials and cultural productions. The pupils' knowledge about the disease was evaluated before the activities and 12 months later. The teachers' acceptance and perceptions were assessed through structured interviews and subsequent thematic analysis. The Shistosoma mansoni infection status of teachers and their students was also assessed using the Kato Katz stool test. RESULTS: The parasitological study showed 31.6% of the teachers and 21.4% of the pupils to be positive for S. mansoni. The teachers' knowledge of important aspects of schistosomiasis transmission and prevention was fragmented and incorrect prior to the training. The teachers' knowledge changed significantly after the training and they were strongly accepting of the pedagogical methods used during the training. The level of their pupils' knowledge about the disease had increased significantly (p < 0.05). However, pupils responded that, even after the educational activities, they still had contact with the city's contaminated waters (p > 0.05). CONCLUSIONS: The results of this study underline the importance of schools and teachers as partners in controlling and eliminating schistosomiasis. Teacher training on the disease significantly increases their pupils' knowledge, reflecting empowerment with regard to local health conditions.

Reliability of point-of-care circulating cathodic antigen assay for diagnosing schistosomiasis mansoni in urine samples from an endemic area of Brazil after one year of storage at -20 degrees Celsius.

BACKGROUND: The World Health Organization recommends reliable point-of-care (POC) diagnostic testing to eliminate schistosomiasis. Lateral flow immunoassay that detects schistosome circulating cathodic antigen (CCA) in urine to establish prevalence thresholds for intervention in endemic areas is recommended. Stored urine may be useful if surveying at-risk populations is delayed or interrupted by unforeseen circumstances, such as the current COVID-19 pandemic. This study evaluated the manufacturer's claim that Schistosoma mansoni infection can be reliably diagnosed in urine samples stored at -20°C for one year. METHODS: Two-hundred-forty-two subjects from an endemic site in Brazil provided one urine sample each for testing with URINE CCA (SCHISTO) ECO TESTE® (POC-ECO) and one stool sample each for testing with Kato-Katz (KK) and Helmintex® (HTX) as a robust reference standard for infection status. At least 2 ml of urine from each participant was stored at -20°C; after one year, 76 samples were randomly selected for POC-ECO retesting. RESULTS: The POC-ECO agreement between freshly collected and stored urine was inadequate considering trace results as positive (Cohen's kappa coefficient κ = 0.08) and negative (κ = 0.36). POC-ECO accuracy was not significantly greater than that of routine KK (54%; 95% confidence interval: 42.1%-65.5%). CONCLUSIONS: The precision and accuracy of POC-ECO have to be optimized in both freshly collected and stored urine before it can be recommended for use in control programs in Brazil.

Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis.

Background: Schistosomiasis is a parasitic disease associated with poverty. It is estimated that 7.1 million people are infected with Schistosoma mansoni in Latin America, with 95% of them living in Brazil. Accurate diagnosis and timely treatment are important measures to control and eliminate schistosomiasis, but diagnostic improvements are needed to detect infections, especially in areas of low endemicity. Methodology: This research aimed to evaluate the performance of 11 diagnostic tests using latent class analysis (LCA). A cross-sectional survey was undertaken in a low endemicity area of the municipality of Malacacheta, Minas Gerais, Brazil. Feces, urine, and blood samples were collected from 400 residents older than 6 years of age, who had not been treated with praziquantel in the 12 months previous to the collection of their samples. The collected samples were examined using parasitological (Helm Test® kit Kato-Katz), nucleic acid amplification tests -NAATs (PCR, qPCR and LAMP on urine; PCR-ELISA, qPCR and LAMP on stool), and immunological (POC-CCA, the commercial anti-Schistosoma mansoni IgG ELISA kit from Euroimmun, and two in-house ELISA assays using either the recombinant antigen PPE or the synthetic peptide Smp150390.1) tests. Results: The positivity rate of the 11 tests evaluated ranged from 5% (qPCR on urine) to 40.8% (commercial ELISA kit). The estimated prevalence of schistosomiasis was 12% (95% CI: 9-15%) according to the LCA. Among all tests assessed, the commercial ELISA kit had the highest estimated sensitivity (100%), while the Kato-Katz had the highest estimated specificity (99%). Based on the accuracy measures observed, we proposed three 2-step diagnostic approaches for the active search of infected people in endemic settings. The approaches proposed consist of combinations of commercial ELISA kit and NAATs tests performed on stool. All the approaches had higher sensitivity and specificity than the mean values observed for the 11 tests (70.4 and 89.5%, respectively). Conclusion: We showed that it is possible to achieve high specificity and sensitivity rates with lower costs by combining serological and NAATs tests, which would assist in the decision-making process for appropriate allocation of public funding aiming to achieve the WHO target of eliminating schistosomiasis as a public health problem by 2030.

Reliability of point-of-care circulating cathodic antigen assay for diagnosing schistosomiasis mansoni in urine samples from an endemic area of Brazil after one year of storage at -20 degrees Celsius

ABSTRACT Background The World Health Organization recommends reliable point-of-care (POC) diagnostic testing to eliminate schistosomiasis. Lateral flow immunoassay that detects schistosome circulating cathodic antigen (CCA) in urine to establish prevalence thresholds for intervention in endemic areas is recommended. Stored urine may be useful if surveying at-risk populations is delayed or interrupted by unforeseen circumstances, such as the current COVID-19 pandemic. This study evaluated the manufacturer's claim that Schistosoma mansoni infection can be reliably diagnosed in urine samples stored at -20°C for one year. Methods Two-hundred-forty-two subjects from an endemic site in Brazil provided one urine sample each for testing with URINE CCA (SCHISTO) ECO TESTE® (POC-ECO) and one stool sample each for testing with Kato-Katz (KK) and Helmintex® (HTX) as a robust reference standard for infection status. At least 2 ml of urine from each participant was stored at -20°C; after one year, 76 samples were randomly selected for POC-ECO retesting. Results: The POC-ECO agreement between freshly collected and stored urine was inadequate considering trace results as positive (Cohen's kappa coefficient κ = 0.08) and negative (κ = 0.36). POC-ECO accuracy was not significantly greater than that of routine KK (54%; 95% confidence interval: 42.1%-65.5%). Conclusions The precision and accuracy of POC-ECO have to be optimized in both freshly collected and stored urine before it can be recommended for use in control programs in Brazil.

Adherence to diagnosis followed by selective treatment of schistosomiasis mansoni and related knowledge among schoolchildren in an endemic area of Minas Gerais, Brazil, prior to and after the implementation of educational actions.

INTRODUCTION: Brazilian guidelines for schistosomiasis elimination recommend regular search of infection carriers and their timely treatment. This study evaluates the effect of educational actions (EAs) among schoolchildren on adherence to diagnosis and treatment, as well as on knowledge of the disease. METHODS: In April/2013, a questionnaire was applied to 6th-to-8th-grade pupils of eight public schools to evaluate prior knowledge of disease and self-reported risk behavior. Baseline parasitological survey (PS) was done in May/2013, followed by selective treatment and cure assessment. The schools were then randomly allocated to experimental (EG) and control (CG) groups, with and without EAs, respectively. EAs were conducted for 3 months from August/2013. Questionnaire was reapplied in November/2013, April/2014, October/2014, and October/2015 to evaluate changes in knowledge about the disease and self-reported risk behavior. Two further annual PSs (May/2014 and May/2015), each followed by treatment of positives, allowed to evaluate between-group differences and intra-group changes in adherence to diagnosis and treatment, and to follow-up prevalence and intensity of infection. RESULTS: Adherence to diagnosis did not differ significantly between EG (84.1%) and CG (81.1%) at baseline but was significantly higher in EG in subsequent PSs. Overall, adherence to treatment was higher than 90% in all three PSs; cure was 98.4%, egg-reduction was 99.8% and reinfection, 2.8%. Prevalence fell significantly in EC (from 23.5% to 6.8%) and CG (from 21.8% to 2.4%), the same occurring with intensity (from 54.2 to 4.6 epg in EG and from 38.4 to 1.3 epg in CG). Disease knowledge increased significantly in EG and CG; knowledge about disease transmission increased significantly more in the EG. Self-reported risk behavior remained above 67% and did not differ significantly between EG and CG. CONCLUSION: EAs increased adherence of schoolchildren and improved knowledge about the disease, confirming that EAs are an important tool to enhance schoolchildren participation in control campaigns.

Low specificity of point-of-care circulating cathodic antigen (POCCCA) diagnostic test in a non-endemic area for schistosomiasis mansoni in Brazil.

A point-of-care test for detecting schistosome circulating cathodic antigen in urine (POCCCA) has been proposed for mapping infection and defining prevalence thresholds for mass drug administration (MDA). However, there is increasing evidence that POCCCA may yield false-positive results, which requires rigorous specificity evaluation in non-endemic areas. POCCCA was applied in an area known to be free from infection and devoid of any condition for schistosomiasis transmission as part of a multicentre study to evaluate the performance of POCCCA in Brazil's low or potentially endemic settings. Besides POCCCA detection in urine, a search for eggs in stool was performed by Kato-Katz (KK) and Helmintex (HTX) methods. One-hundred-and-seventy-four participants returned urine samples, 140 of which delivered stool samples. All these were HTX-negative for Schistosoma mansoni, and all 118 tested with KK were negative for both S. mansoni and soil-transmitted helminths. POCCCA results from freshly collected urine yielded a specificity of 62.1% (95% CI: 53.6% - 70.2%), taking trace outcomes as positive according to the manufacturer's instructions. Retesting urine from the 140 HTX-negatives after one-year storage at -20 °C with two new POCCCA batches simultaneously yielded significantly different specificities (34.3%; 95%CI: 26.5% - 42.8% and 75.0%; 95% CI: 67.0% - 81.9%). These two batches had a weak agreement (Cohen's kappa: 0.56; 95%CI: 0.44-0.68) among the 174 urine samples retested. At present, POCCCA cannot be recommended either as a cut-off point for MDA or a reliable diagnostic tool for treatment of the infection carriers (selective chemotherapy) in low endemic areas and at final stages of transmission interruption. Manufacturers should be required to optimize production standardization and to assure quality and reproducibility of the test. Extended rigorous performance evaluations by different users from different regions are needed before POCCCA is widely recommended.

Schistosoma mansoni infection and related knowledge among schoolchildren in an endemic area of Minas Gerais, Brazil, prior to educational actions.

As a signatory to World Health Assembly Resolution WHA65.21 on eliminating schistosomiasis, the Brazilian Ministry of Health (MoH) recommends early identification and timely treatment of the infection carriers for morbidity control, plus complementary preventive measures, such as health education, for transmission control. This study reports infection and awareness of schistosomiasis among schoolchildren before the implementation of school-based educational actions in an endemic municipality with persisting moderate prevalence levels despite successive control campaigns since the late 1990s. A questionnaire was applied in April 2013 to schoolchildren in the middle years of schooling (6th to 8th year) of Malacacheta municipality to assess baseline knowledge and risk behaviour related to schistosomiasis. A stool survey was conducted in May/June 2013 in 2519 schoolchildren from all years of fundamental education (first to 9th year) to identify the infection carriers, as well as to assess baseline prevalence and intensity of infection using the Kato-Katz method (one sample, two slides). The infected schoolchildren were treated promptly with single-dose praziquantel 60mg/kg and followed up after 45days for treatment efficacy. Relevant outcomes from baseline stool survey, treatment and follow-up were statistically evaluated in relation to area of residence (rural/urban), gender, age group (<11/≥years) and infection. Adherence to baseline survey was 81.2%, and prevalence of infection was 21.4%. Of the 539 positives, 60 (11.1%) had ≥400 eggs per gram of faeces (heavy-intensity infection). Prevalence of infection was significantly higher among rural residents and≥11year olds, whereas intensity of infection was higher among rural residents,≥11year olds and boys. Adherence by the positives to treatment was 93.3% and adherence by the treated children to 45-day follow-up was 72.2%. At 45days after treatment, 97.0% of the 363 children surveyed were egg-negative; the egg reduction rate was 99.4%. Of the 924 children who responded to the questionnaire, 95.5% showed awareness of schistosomiasis, although 76.2% reported contact with natural, unsafe bodies of water. Reported contact with water was significantly more frequent among infected than non-infected, and boys than girls. The results show persisting infection and risk behaviour among schoolchildren, regardless of their basic knowledge about schistosomiasis. These are grounds for implementing specific educational actions to improve awareness and behavioural change, jointly with other control measures, to attain the MoH goals.

Assessment of schistosomiasis in the semi-arid Northeast region of Brazil: the São Francisco River large-scale water transposition project.

UNLABELLED: INTRODUCTION Risk of schistosomiasis expansion to semi-arid northeastern Brazil under the influence of the Integration Project of the São Francisco River (IPSFR) was assessed. METHODS: Stool examinations of schoolchildren, epidemiological investigation, and survey of the local host snail Biomphalaria straminea were performed in five IPSFR municipalities. RESULTS Six of 4,770 examined schoolchildren were egg-positive for Schistosoma mansoni. Biomphalaria straminea was widespread, but not naturally infected with S. mansoni. Snails experimentally exposed to two laboratory S. mansoni strains yielded infection indices of 1-4.5%. CONCLUSIONS: There is evidence of active schistosomiasis transmission in the area; thus, intensive surveillance actions are required.

School-based and community-based actions for scaling-up diagnosis and treatment of schistosomiasis toward its elimination in an endemic area of Brazil.

This study evaluated a school-based and a community-based scheme for diagnosis, treatment and follow-up of schistosomiasis mansoni among school-aged children in views of resolution CD49.R19 of the Pan American Health Organization toward the elimination of schistosomiasis as a public health problem in the Americas and subsequent commitments endorsed by the Brazilian government. The school-aged population from a representative municipality of the endemic area of Northeastern Brazil was randomly allocated to either school-based or community-based scheme. The two schemes were compared with regard to coverage of diagnosis by the Kato-Katz method (KK) at baseline, treatment of the positives for Schistosoma mansoni with praziquantel, treatment of the positives for soil-transmitted helminthes (STH) with mebendazole, as well as follow-up of treatment efficacy and reinfection assessed respectively at four and 12 months after treatment. Nutritional status of the positives for S. mansoni was assessed at baseline and re-assessed at 12 months after treatment. Coverage of diagnosis and treatment was satisfactory (>75%) in both schemes. Diagnosis coverage at baseline and at 12 months was significantly higher in the community scheme, whereas treatment coverage did not differ significantly between the two schemes either at baseline or at 12 months. The number of children covered per day was significantly higher in the schools than in the community at baseline but not at follow-up, when daily coverage was higher in the community. With regard to S. mansoni, overall treatment efficacy rate at four months was 90.8%, and reinfection rate at 12 months was 21.6%. For STH, overall treatment efficacy was 45.4% and reinfection, 32.8%. The nutritional status of the positives for S. mansoni at baseline did not change significantly at 12 months post-treatment. Actions targeted at this particularly vulnerable high-risk group should combine school-based and community-based interventions as well as preventive measures to reduce transmission.

A multicentre randomized controlled trial of the efficacy and safety of single-dose praziquantel at 40 mg/kg vs. 60 mg/kg for treating intestinal schistosomiasis in the Philippines, Mauritania, Tanzania and Brazil.

BACKGROUND: Praziquantel at 40 mg/kg in a single dose is the WHO recommended treatment for all forms of schistosomiasis, but 60 mg/kg is also deployed nationally. METHODOLOGY/PRINCIPAL FINDINGS: Four trial sites in the Philippines, Mauritania, Tanzania and Brazil enrolled 856 patients using a common protocol, who were randomised to receive praziquantel 40 mg/kg (n  =  428) or 60 mg/kg (n  =  428). While the sites differed for transmission and infection intensities (highest in Tanzania and lowest in Mauritania), no bias or heterogeneity across sites was detected for the main efficacy outcomes. The primary efficacy analysis was the comparison of cure rates on Day 21 in the intent-to-treat population for the pooled data using a logistic model to calculate Odd Ratios allowing for baseline characteristics and study site. Both doses were highly effective: the Day 21 cure rates were 91.7% (86.6%-98% at individual sites) with 40 mg/kg and 92.8% (88%-97%) with 60 mg/kg. Secondary parameters were eggs reduction rates (ERR), change in intensity of infection and reinfection rates at 6 and 12 months. On Day 21 the pooled estimate of the ERR was 91% in both arms. The Hazard Ratio for reinfections was only significant in Brazil, and in favour of 60 mg/kg on the pooled estimate (40 mg/kg: 34.3%, 60 mg/kg: 23.9%, HR  =  0.78, 95% CI  = [0.63;0.96]). Analysis of safety could not distinguish between disease- and drug-related events. 666 patients (78%) reported 1327 adverse events (AE) 4 h post-dosing. The risk of having at least one AE was higher in the 60 than in the 40 mg/kg group (83% vs. 73%, p<0.001). At 24 h post-dosing, 456 patients (54%) had 918 AEs with no difference between arms. The most frequent AE was abdominal pain at both 4 h and 24 h (40% and 24%). CONCLUSION: A higher dose of 60 mg/kg of praziquantel offers no significant efficacy advantage over standard 40 mg/kg for treating intestinal schistosomiasis caused by either S. mansoni or S. japonicum. The results of this study support WHO recommendation and should be used to inform policy decisions in the countries.

The prevalence of schistosomiasis in school-aged children as an appropriate indicator of its prevalence in the community.

School-aged children (6-15 years) from the endemic area of Pernambuco were evaluated both as a target group for and an indicator of schistosomiasis control in the community. Parasitological data were drawn from baseline stool surveys of whole populations that were obtained to diagnose Schistosoma mansoni infection. Nineteen representative localities were selected for assessing the prevalence of schistosomiasis among individuals in the following age groups: 0-5, 6-15, 16-25, 26-40 and 41-80 years. For each locality, the prevalence in each age group was compared to that of the overall population using contingency table analysis. To select a reference group, the operational difficulties of conducting residential surveys were considered. School-aged children may be considered to be the group of choice as the reference group for the overall population for the following reasons: (i) the prevalence of schistosomiasis in this age group had the highest correlation with the prevalence in the overall population (r = 0.967), (ii) this age group is particularly vulnerable to infection and plays an important role in parasite transmission and (iii) school-aged children are the main target of the World Health Organization in terms of helminth control. The Schistosomiasis Control Program should consider school-aged children both as a reference group for assessing the need for intervention at the community level and as a target group for integrated health care actions of the Unified Health System that are focused on high-risk groups.

Spatial distribution of Schistosoma mansoni infection before and after chemotherapy with two praziquantel doses in a community of Pernambuco, Brazil.

Praziquantel chemotherapy has been the focus of the Schistosomiasis Control Program in Brazil for the past two decades. Nevertheless, information on the impact of selective chemotherapy against Schistosoma mansoni infection under the conditions confronted by the health teams in endemic municipalities remains scarce. This paper compares the spatial pattern of infection before and after treatment with either a 40 mg/kg or 60 mg/kg dose of praziquantel by determining the intensity of spatial cluster among patients at 180 and 360 days after treatment. The spatial-temporal distribution of egg-positive patients was analysed in a Geographic Information System using the kernel smoothing technique. While all patients became egg-negative after 21 days, 17.9% and 30.9% reverted to an egg-positive condition after 180 and 360 days, respectively. Both the prevalence and intensity of infection after treatment were significantly lower in the 60 mg/kg than in the 40 mg/kg treatment group. The higher intensity of the kernel in the 40 mg/kg group compared to the 60 mg/kg group, at both 180 and 360 days, reflects the higher number of reverted cases in the lower dose group. Auxiliary, preventive measures to control transmission should be integrated with chemotherapy to achieve a more enduring impact.

Spatial distribution of Schistosoma mansoni infection before and after chemotherapy with two praziquantel doses in a community of Pernambuco, Brazil

Praziquantel chemotherapy has been the focus of the Schistosomiasis Control Program in Brazil for the past two decades. Nevertheless, information on the impact of selective chemotherapy against Schistosoma mansoni infection under the conditions confronted by the health teams in endemic municipalities remains scarce. This paper compares the spatial pattern of infection before and after treatment with either a 40 mg/kg or 60 mg/kg dose of praziquantel by determining the intensity of spatial cluster among patients at 180 and 360 days after treatment. The spatial-temporal distribution of egg-positive patients was analysed in a Geographic Information System using the kernel smoothing technique. While all patients became egg-negative after 21 days, 17.9 percent and 30.9 percent reverted to an egg-positive condition after 180 and 360 days, respectively. Both the prevalence and intensity of infection after treatment were significantly lower in the 60 mg/kg than in the 40 mg/kg treatment group. The higher intensity of the kernel in the 40 mg/kg group compared to the 60 mg/kg group, at both 180 and 360 days, reflects the higher number of reverted cases in the lower dose group. Auxiliary, preventive measures to control transmission should be integrated with chemotherapy to achieve a more enduring impact.

The prevalence of schistosomiasis in school-aged children as an appropriate indicator of its prevalence in the community

School-aged children (6-15 years) from the endemic area of Pernambuco were evaluated both as a target group for and an indicator of schistosomiasis control in the community. Parasitological data were drawn from baseline stool surveys of whole populations that were obtained to diagnose Schistosoma mansoni infection. Nineteen representative localities were selected for assessing the prevalence of schistosomiasis among individuals in the following age groups: 0-5, 6-15, 16-25, 26-40 and 41-80 years. For each locality, the prevalence in each age group was compared to that of the overall population using contingency table analysis. To select a reference group, the operational difficulties of conducting residential surveys were considered. School-aged children may be considered to be the group of choice as the reference group for the overall population for the following reasons: (i) the prevalence of schistosomiasis in this age group had the highest correlation with the prevalence in the overall population (r = 0.967), (ii) this age group is particularly vulnerable to infection and plays an important role in parasite transmission and (iii) school-aged children are the main target of the World Health Organization in terms of helminth control. The Schistosomiasis Control Program should consider school-aged children both as a reference group for assessing the need for intervention at the community level and as a target group for integrated health care actions of the Unified Health System that are focused on high-risk groups.

A rationale for schistosomiasis control in elementary schools of the rainforest zone of pernambuco, Brazil.

BACKGROUND: Since its beginning in 1999, the Schistosomiasis Control Program within the Unified Health System (PCE-SUS) has registered a cumulative coverage of just 20% of the population from the Rainforest Zone of Pernambuco (ZMP), northeast Brazil. This jeopardizes the accomplishment of the minimum goal of the Fifty-Fourth World Health Assembly, resolution WHA54.19, of providing treatment for schistosomiasis and soil-transmitted helminthiases (STH) to 75% of school-aged children at risk, which requires attending at least 166,000 residents in the 7-14 age range by year 2010 in that important endemic area. In the present study, secondary demographic and parasitological data from a representative municipality of the ZMP are analyzed to provide evidence that the current, community-based approach to control schistosomiasis and STH is unlikely to attain the WHA-54.19 minimum goal and to suggest that school-based control actions are also needed. METHODOLOGY/PRINCIPAL FINDINGS: Data available on the PCE-SUS activities related to diagnosis and treatment of the population from the study municipality were obtained from the State Secretary of Health of Pernambuco (SES/PE) for 2002-2006, complemented by the Municipal Secretary of Health (SMS) for 2003-2004. Data from a school-based stool survey carried out by the Schistosomiasis Reference Service of the Oswaldo Cruz Foundation (SRE/Fiocruz) in 2004 were used to provide information on infection status variation among school-aged children (7-14 years). According to the SES, from 2004 to 2006, only 2,977 (19.5%) of the estimated 15,288 residents of all ages were examined, of which 396 (13.3%) were positive for Schistosoma mansoni. Among these, only 180 (45.5%) were treated. According to the SMS, of the 1,766 examined in the 2003-2004 population stool survey 570 (32.3%) were children aged 7-14 years. One year later, the SRE/Fiocruz school survey revealed that the infection status among those children remained unchanged at 14%-15% prevalence. By 2006, the school-aged population was estimated at 2,981, of which 2,007 (67.3%) were enrolled as pupils. CONCLUSIONS: It is suggested that in the most troubled municipalities individual diagnosis and treatment should be concentrated in school-aged children rather than the whole population. School-based actions involving teachers and children's families may help the health teams to scale up control actions in order to attain the WHA-54.19 minimum goal. This strategy should involve health and education organs and include both enrolled and non-enrolled children.

Discriminating acute from chronic human schistosomiasis mansoni.

Specific immunoglobulin (IgA, IgG and IgM) responses to different antigen targets (soluble eggs antigen--SEA, soluble worm adult protein--SWAP and keyhole limpet hole--KLH) were measured by enzyme linked immunosorbent assay (ELISA) in patients with acute and chronic schistosomiasis, as well as patients without schistosomiasis. SEA IgA and KLH IgM presented high discriminatory powers to distinguish acute from chronic schistosomiasis, with calculated areas under the curve (AUCs) of 0.88 and 0.82, respectively, obtained from receiver operating characteristic (ROC) curve. On the other hand, these tests, particularly SEA IgA were not useful to distinguish schistosomiasis (including the acute and chronic forms) from individuals without this disease, but infected with other intestinal parasites (Ascaris lumbricoides, Trichuris trichiura and hookworm). By contrast, SWAP IgG and SEA IgG were able to discriminate schistosomiasis patients from healthy individuals and patients infected with other parasites (AUCs of 0.96 and 0.85, respectively). Thus, it is possible to use a combination of serological tests, such as SEA IgA and SWAP IgG, to simultaneously establish the diagnosis of schistosomiasis and discriminate the acute from the chronic forms of the disease.