Prevalence of helmintic infections in Brazilian Maxakali indigenous: a repeated cross-sectional design.

BACKGROUND: The prevalence of intestinal parasites is known to be high among Amerindian populations; further, there are serious problems in the healthcare of these populations in Brazil. The Maxakali, located in the northeastern region of Minas Gerais, Brazil, is an indigenous group that still preserves many of its cultural aspects. This study aimed to compare the positivity rate of schistosomiasis and soil-transmitted helminths in this ethnic group in epidemiological surveys conducted in 1972 and 2014. METHODS: Stool parasitological examinations were performed by the Kato-Katz technique during both periods in this population. In 2014, the parasitological diagnosis was also realized with the TF-Test® technique. RESULTS: In 1972, 270 inhabitants were examined. The positivity rates were 67.4% for Schistosoma mansoni, 72.9% for hookworms, 43.7% for Ascaris lumbricoides, and 23.7% for Trichuris trichiura. In 2014, 545 individuals were examined, and the positivity rates obtained were 45.7% for S. mansoni, 22.8% for hookworms, 0.6% for A. lumbricoides, and 2.8% for T. trichiura. CONCLUSIONS: The comparison of the parasitological surveys conducted in 1972 and 2014, indicates that the indigenous Maxakali remained neglected by the health and indigenous protection authorities during these four decades. The infection rate observed in 2014 for schistosomiasis and hookworm remains high, considering the current epidemiological view of these diseases in the Brazilian population.

A Real-Time PCR Assay for the Diagnosis of Intestinal Schistosomiasis and Cure Assessment After the Treatment of Individuals With Low Parasite Burden.

The laboratorial diagnosis of the intestinal schistosomiasis is always performed using Kato-Katz technique. However, this technique presents low sensitivity for diagnosis of individuals with low parasite burden, which constitutes the majority in low endemicity Brazilian locations for the disease. The objective of this study was developed and to validate a real-time PCR assay (qPCR) targeting 121 bp sequence to detect Schistosoma spp. DNA for the diagnosis of intestinal schistosomiasis and a sequence of the human ß-actin gene as internal control. Firstly, the qPCR was standardized and next it was evaluated for diagnosis and cure assessment of intestinal schistosomiasis in the resident individuals in Tabuas and Estreito de Miralta, two locations in Brazil endemic for intestinal schistosomiasis. The qPCR assay results were compared with those of the Kato-Katz (KK) test, examining 2 or 24 slides, Saline Gradient (SG) and "reference test" (24 KK slides + SG). The cure assessment was measured by these diagnostic techniques at 30, 90, and 180 days post-treatment. In Tabuas, the positivity rates obtained by the qPCR was 30.4% (45/148) and by "reference test" was of 31.0% (46/148), with no statistical difference (p = 0.91). The presumed cure rates at 30, 90, and 180 days post-treatment were 100, 94.4, and 78.4% by the analysis of 24 KK slides, 100, 94.4, and 78.4% by the SG, and 100, 83.3, and 62.1% by the qPCR assay. In Estreito de Miralta, the positivity obtained by qPCR was 18.3% (26/142) and with "reference test" was 24.6% (35/142), with no statistical difference (p = 0.20). The presumed cure rates were 93.3, 96.9, and 96.5% by the KK, 93.3, 96.9, and 100% by the SG, and 93.3, 93.9, and 96.5% by the qPCR at 30, 90, and 180 days post-treatment, respectively. This study showed that the diagnostic techniques presented different performance in the populations from the two districts (Tabuas and Estreito de Miralta) and reinforces the need of combining techniques to improve diagnosis accuracy, increasing the detection of individuals with low parasite burden. This combination of techniques consists an important strategy for controlling the disease transmission.

Transmission control of schistosomiasis mansoni in a low endemicity area through a single intervention with rigorous prospection of infected cases treated with praziquantel: evaluation after 7 years of intervention.

A prospective cohort study with rigorous searching for schistosomiasis cases was conducted among residents of Pedra Preta, Montes Claros, Minas Gerais State, Brazil, seven years after an intervention. Kato-Katz (KK), Saline Gradient, Miracidia Hatch and Polymerase Chain Reaction (PCR) were used as the diagnostic methods in 2008. In the period of 2013-2016, 175 patients remaining in the area were examined using the diagnostic methods Kato-Katz (24 slides, 1 g of feces) and Saline Gradient (2 procedures, 1 g of feces). Sixty-eight out of the 69 infected and treated individuals in 2008 tested negative. The percentage of new cases was 2.29% (4/175), and the 4 infected individuals presented low parasitic load [1, 6, 7 and 19 eggs per gram (EPG)]. All the participants answered epidemiological questionnaires on risky behavior. All residences had pit latrines and domiciliary water supply. The primary transmission focus (lake) was dry for several months. Malacological surveys showed a few non-infected specimens of Biomphalaria glabrata . A clear dominance of Biomphalaria straminea was observed. It can be inferred that a significant decrease in the disease transmission occurred after a single action through an intense search for infected and treated cases under the ecoepidemiological conditions of this area.

Diagnosis of Schistosoma mansoni infections: what are the choices in Brazilian low-endemic areas?

The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then subsequent confirmation of positive cases by intensive parasitological investigations.

Serological proteomic screening and evaluation of a recombinant egg antigen for the diagnosis of low-intensity Schistosoma mansoni infections in endemic area in Brazil.

BACKGROUND: Despite decades of use of control programs, schistosomiasis remains a global public health problem. To further reduce prevalence and intensity of infection, or to achieve the goal of elimination in low-endemic areas, there needs to be better diagnostic tools to detect low-intensity infections in low-endemic areas in Brazil. The rationale for development of new diagnostic tools is that the current standard test Kato-Katz (KK) is not sensitive enough to detect low-intensity infections in low-endemic areas. In order to develop new diagnostic tools, we employed a proteomics approach to identify biomarkers associated with schistosome-specific immune responses in hopes of developing sensitive and specific new methods for immunodiagnosis. METHODS AND FINDINGS: Immunoproteomic analyses were performed on egg extracts of Schistosoma mansoni using pooled sera from infected or non-infected individuals from a low-endemic area of Brazil. Cross reactivity with other soil-transmitted helminths (STH) was determined using pooled sera from individuals uniquely infected with different helminths. Using this approach, we identified 23 targets recognized by schistosome acute and chronic sera samples. To identify immunoreactive targets that were likely glycan epitopes, we compared these targets to the immunoreactivity of spots treated with sodium metaperiodate oxidation of egg extract. This treatment yielded 12/23 spots maintaining immunoreactivity, suggesting that they were protein epitopes. From these 12 spots, 11 spots cross-reacted with sera from individuals infected with other STH and 10 spots cross-reacted with the negative control group. Spot number 5 was exclusively immunoreactive with sera from S. mansoni-infected groups in native and deglycosylated conditions and corresponds to Major Egg Antigen (MEA). We expressed MEA as a recombinant protein and showed a similar recognition pattern to that of the native protein via western blot. IgG-ELISA gave a sensitivity of 87.10% and specificity of 89.09% represented by area under the ROC curve of 0.95. IgG-ELISA performed better than the conventional KK (2 slides), identifying 56/64 cases harboring 1-10 eggs per gram of feces that were undiagnosed by KK parasitological technique. CONCLUSIONS: The serological proteome approach was able to identify a new diagnostic candidate. The recombinant egg antigen provided good performance in IgG-ELISA to detect individuals with extreme low-intensity infections (1 egg per gram of feces). Therefore, the IgG-ELISA using this newly identified recombinant MEA can be a useful tool combined with other techniques in low-endemic areas to determine the true prevalence of schistosome infection that is underestimated by the KK method. Further, to overcome the complexity of ELISA in the field, a second generation of antibody-based rapid diagnostic tests (RDT) can be developed.

Diagnosis of Schistosoma mansoni infections: what are the choices in Brazilian low-endemic areas?

The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then subsequent confirmation of positive cases by intensive parasitological investigations.

Prevalence of schistosomiasis mansoni in indigenous Maxakali villages, Minas Gerais, Brazil.

Intestinal parasitic infections are a common health problem among Amerindian populations and schistosomiasis represents one of the most prevalent diseases in Maxakali people. The Kato-Katz is the diagnostic method recommended by WHO for epidemiological studies; however, one of the technique's limitations is the failure to detect parasites in individuals with low parasite load. The aim of this study was to establish the prevalence of Schistosoma mansoni in indigenous Maxakali villages, evaluating the TF-Test® performance for diagnosis compared to the Kato-Katz technique. Stool samples from 545 individuals were processed by the TF-Test® (1 sample) and Kato-Katz (1 slide). The positivity rate for S. mansoni by Kato-Katz was 45.7%. The rate by the TF-Test® was 33.2%, and 51.9% by the combined parasitological techniques. The amplitude of parasite load was 24 to 4,056 eggs per gram of feces (epg), with a geometric mean of 139 epg. The co-positivity, co-negativity, and accuracy values by TF-Test® in relation to Kato-Katz were 59.0%, 88.5%, and 75.0%, respectively. The agreement between these techniques was moderate (k=0.486) as determined by the kappa index. Thus, the results of this study demonstrated that the performance of Kato-Katz was superior (p <0.05) to that of TF-Test® in the detection of S. mansoni. The combination of TF-Test® and Kato-Katz resulted in an increased positivity rate of S. mansoni, demonstrating the high risk of infection to which indigenous populations are exposed and the importance of the implementation of control strategies in Maxakali villages.

Development of a laboratorial platform for diagnosis of schistosomiasis mansoni by PCR-ELISA.

OBJECTIVE: We developed a laboratorial platform to release a commercial platform used in the PCR-ELISA for the molecular diagnosis of schistosomiasis mansoni. On following, PCR-ELISA platform laboratorial was evaluated in 206 feces samples collected of individual living in a Brazilian low endemicity area. RESULTS: The PCR-ELISA laboratorial platform indicated a prevalence rate of 25.2%, which was higher than the Kato-Katz technique (18.4%) and lower than the commercial platform (30.1%). Considering Kato-Katz technique as the reference, there were 97.4% and 91.1% of relative sensitivity and specificity rates, respectively. The laboratorial platform presented good precision, performance diagnostic, and can be used in replacement to the commercial platform for diagnosis of schistosomiasis by PCR-ELISA.

Performance of POC-CCA® in diagnosis of schistosomiasis mansoni in individuals with low parasite burden.

INTRODUCTION: Schistosomiasis, caused by Schistosoma mansoni, is a public health concern in Brazil. However, the most popular diagnostic method, the Kato-Katz technique, exhibits low sensitivity in low-endemicity areas. We aimed to compare the performance of an immunological assay, the point-of-care circulating cathodic antigen (POC-CCA®) test, with that of two parasitological techniques in a low-endemicity population. METHODS: Our study included 141 individuals living in Estreito de Miralta, Minas Gerais, Brazil. Fecal samples were obtained from all participants and analyzed for schistosomiasis using two parasitological techniques: the Kato-Katz technique and the saline gradient technique. Additionally, POC-CCA® strips were utilized for testing urine samples. The results obtained by the different techniques were compared. RESULTS: Analysis of two or 24 slides using the Kato-Katz technique resulted in a positivity rate of 10.6% (15/141) or 19.1% (27/141), respectively. The saline gradient technique yielded a positivity rate of 17.0% (24/141). The prevalence according to both parasitological techniques was 24.1% (34/141). The POC-CCA® test yielded a positivity rate of 22.7% (32/141); however, the positivity rate was merely 2.1% if trace results were considered negative. The agreements observed between POC-CCA® and the parasitological techniques were good (Kappa indexes > 0.64). The POC-CCA® test was more sensitive than the two-slide Kato-Katz technique (p < 0.05) in detecting cases of S. mansoni infection when trace results were considered positive. CONCLUSIONS: These findings reinforce the importance of using multiple diagnostic techniques in low-endemicity areas for effective control of disease.

Improvement of POC-CCA Interpretation by Using Lyophilization of Urine from Patients with Schistosoma mansoni Low Worm Burden: Towards an Elimination of Doubts about the Concept of Trace.

BACKGROUND: Accurate diagnostic techniques for schistosomiasis are essential for prevalence determination and identification of positive patients. A point-of-care test for detecting schistosome circulating cathodic antigen (POC-CCA) has been evaluated for its accuracy in different endemic regions. This reagent strip/dipstick based assay has showed high sensitivity for individuals with high or moderate worm burden, but the interpretation of light infections is less clear, especially for trace readings. METHODOLOGY/PRINCIPAL FINDINGS: We introduced a urine lyophilization step to the POC-CCA assay to improve its sensitivity and clarify the interpretation of traces. We evaluated POC-CCA sensitivity and specificity within individuals with low parasite burdens in a Brazilian endemic area where a high number of traces were detected. Patients that were positive for other helminths were also evaluated for cross reactions. In all cases, a combined parasitological diagnosis using Kato-Katz (24 slides) and Saline Gradient (1 g of feces) were used as reference. At baseline, diagnosis by POC-CCA (1-2 cassettes) showed 6% sensitivity, inaccurately predicting a low prevalence of Schistosoma mansoni infections (2 POC-CCA positives/32 egg positives). After urine lyophilization, the sensitivity was increased significantly (p < 0.05). Prevalence rates changed from 2% to 32% (27 POC-CCA positives/32 egg positives), equivalent to parasitological techniques. Most of the trace readings changed to positive after lyophilization while some negatives turned into traces. Cross reaction analysis confirmed the specificity of POC-CCA. CONCLUSIONS/SIGNIFICANCE: Trace readings cannot be primarily defined as positive or negative cases. It is critical to verify case-by-case by concentrating urine 10 fold by lyophilization for the diagnosis. Following lyophilization, persistent trace readings should be read as negatives. No trained technician is needed and cost is restricted to the cost of a lyophilizer and the electricity to run it.

Performance of POC-CCA® in diagnosis of schistosomiasis mansoni in individuals with low parasite burden

Abstract: INTRODUCTION: Schistosomiasis, caused by Schistosoma mansoni, is a public health concern in Brazil. However, the most popular diagnostic method, the Kato-Katz technique, exhibits low sensitivity in low-endemicity areas. We aimed to compare the performance of an immunological assay, the point-of-care circulating cathodic antigen (POC-CCA®) test, with that of two parasitological techniques in a low-endemicity population. METHODS: Our study included 141 individuals living in Estreito de Miralta, Minas Gerais, Brazil. Fecal samples were obtained from all participants and analyzed for schistosomiasis using two parasitological techniques: the Kato-Katz technique and the saline gradient technique. Additionally, POC-CCA® strips were utilized for testing urine samples. The results obtained by the different techniques were compared. RESULTS: Analysis of two or 24 slides using the Kato-Katz technique resulted in a positivity rate of 10.6% (15/141) or 19.1% (27/141), respectively. The saline gradient technique yielded a positivity rate of 17.0% (24/141). The prevalence according to both parasitological techniques was 24.1% (34/141). The POC-CCA® test yielded a positivity rate of 22.7% (32/141); however, the positivity rate was merely 2.1% if trace results were considered negative. The agreements observed between POC-CCA® and the parasitological techniques were good (Kappa indexes > 0.64). The POC-CCA® test was more sensitive than the two-slide Kato-Katz technique (p < 0.05) in detecting cases of S. mansoni infection when trace results were considered positive. CONCLUSIONS: These findings reinforce the importance of using multiple diagnostic techniques in low-endemicity areas for effective control of disease.

Evaluation of parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni in a low transmission area.

This study evaluated parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni. A population-based study was performed in 201 inhabitants from a low transmission locality named Pedra Preta, municipality of Montes Claros, state of Minas Gerais, Brazil. Four stool samples were analysed using two techniques, the Kato-Katz® (KK) technique (18 slides) and the TF-Test®, to establish the infection rate. The positivity rate of 18 KK slides of four stool samples was 28.9% (58/201) and the combined parasitological techniques (KK+TF-Test®) produced a 35.8% positivity rate (72/201). Furthermore, a polymerase chain reaction (PCR)-ELISA assay produced a positivity rate of 23.4% (47/201) using the first sample. All 72 patients with positive parasitological exams were treated with a single dose of Praziquantel® and these patients were followed-up 30, 90 and 180 days after treatment to establish the cure rate. Cure rates obtained by the analysis of 12 KK slides were 100%, 100% and 98.4% at 30, 90 and 180 days after treatment, respectively. PCR-ELISA revealed cure rates of 98.5%, 95.5% and 96.5%, respectively. The diagnostic and assessment of cure for schistosomiasis may require an increased number of KK slides or a test with higher sensitivity, such as PCR-ELISA, in situations of very low parasite load, such as after therapeutic interventions.

Evaluation of parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni in a low transmission area

This study evaluated parasitological and molecular techniques for the diagnosis and assessment of cure of schistosomiasis mansoni. A population-based study was performed in 201 inhabitants from a low transmission locality named Pedra Preta, municipality of Montes Claros, state of Minas Gerais, Brazil. Four stool samples were analysed using two techniques, the Kato-Katz® (KK) technique (18 slides) and the TF-Test®, to establish the infection rate. The positivity rate of 18 KK slides of four stool samples was 28.9% (58/201) and the combined parasitological techniques (KK+TF-Test®) produced a 35.8% positivity rate (72/201). Furthermore, a polymerase chain reaction (PCR)-ELISA assay produced a positivity rate of 23.4% (47/201) using the first sample. All 72 patients with positive parasitological exams were treated with a single dose of Praziquantel® and these patients were followed-up 30, 90 and 180 days after treatment to establish the cure rate. Cure rates obtained by the analysis of 12 KK slides were 100%, 100% and 98.4% at 30, 90 and 180 days after treatment, respectively. PCR-ELISA revealed cure rates of 98.5%, 95.5% and 96.5%, respectively. The diagnostic and assessment of cure for schistosomiasis may require an increased number of KK slides or a test with higher sensitivity, such as PCR-ELISA, in situations of very low parasite load, such as after therapeutic interventions.

Diagnóstico da esquistossomose mansoni em áreas de baixa transmissão: Avaliação de diferentes técnicas (Kato-Katz, Gradiente Salínico, PCR-ELISA e qPCR), antes e após intervenção terapêutica

Este estudo populacional foi realizado em duas localidades endêmicas para a esquistossomose, Tabuas e Estreito de Miralta, pertencentes ao município de Montes Claros, região norte de Minas Gerais, empregando-se duas técnicas parasitológicas e dois ensaios moleculares para o diagnóstico da esquistossomose mansoni. Uma amostra fecal foi obtida de todos participantes e examinada utilizando a técnica de Kato-Katz (24 lâminas = 1000 mg) e a técnica do Gradiente Salínico, utilizando duas porções de 500 mg, totalizando 1000 mg de fezes. Além disso, os ensaios de PCR-ELISA e qPCR foram realizados em DNA extraído de 1000 mg de fezes. Os resultados obtidos pelas diferentes técnicas foram analisados individualmente e comparativamente entre eles. Todos os indivíduos que apresentaram ovos de Schistosoma mansoni ou outros helmintos foram tratados com praziquantel ou albendazol, respectivamente. Para avaliação de cura após o tratamento, amostras de fezes dos indivíduos positivos para S. mansoni, foram coletadas 30, 90 e 180 dias após o tratamento, e examinadas pelas técnicas parasitológicas e pelos ensaios moleculares.

Na localidade de Tabuas, a taxa de positividade, obtida pelo exame de duas lâminas pela técnica de Kato-Katz, foi de 15,5% (23/148), pela análise de 24 lâminas de Kato-Katz 20,9% (31/148) e a obtida pela técnica do Gradiente Salínico foi de 29,0% (43/148) (p< 0,05). A prevalência obtida pela combinação dos resultados das duas técnicas parasitológicas foi de 31,0% (46/148). O ensaio de PCR-ELISA apresentou taxa de positividade de 25,0% (37/148) e ensaio de qPCR, 30,4% (45/148). Na localidade Estreito de Miralta, a taxa de positividade obtida pelo exame de duas lâminas pela técnica de Kato-Katz foi de 10,5% (15/142). As técnicas de Kato-Katz (24 lâminas) e do Gradiente Salínico revelaram taxas de positividade de 19,7% (28/142) e 18,3% (26/142) (p= 0,802), respectivamente. A prevalência obtida pela combinação dos resultados das técnicas parasitológicas foi de 24,6% (35/142). O ensaio de qPCR apresentou taxa de positividade de 18,3% (26/142). Na localidade de Tabuas, as taxas de cura obtidas pelas técnicas parasitológicas Kato-Katz e Gradiente Salínico, 30, 90 e 180 dias após o tratamento foram 100%, 91,6% e 78,4%, respectivamente. Pelo ensaio de PCR-ELISA as taxas de cura obtidas foram de 89,7%, 88,8% e 67,5% e pelo ensaio de qPCR, as taxas de cura foram 100%, 83,3% e 62,1%, nas mesmas etapas de acompanhamento. Na localidade de Estreito de Miralta, as taxas de cura obtidas pelas técnicas de Kato-Katz e GS foram 93,3%, 96,9% e 96,5% (30, 90 e 180 dias após o tratamento, respectivamente) e pelo ensaio de qPCR foram 93,3%, 93,9% e 96,5% nas mesmas etapas de acompanhamento. Este estudo reforça a necessidade de se combinar técnicas com o objetivo de melhorar a acurácia diagnóstica, aumentando a chance de detectar indivíduos com carga parasitária baixa, reduzindo assim a contribuição destes para a manutenção da transmissão

Diagnóstico da esquistossomose mansoni em áreas de baixa transmissão: Avaliação de diferentes técnicas (Kato-Katz, Gradiente Salínico, PCR-ELISA e qPCR), antes e após intervenção terapêutica / Diagnosis of schistosomiasis in areas of low transmission: Evaluation of different techniques (Kato-Katz, Salínico Gradient, PCR-ELISA and qPCR) before and after therapeutic intervention

Este estudo populacional foi realizado em duas localidades endêmicas para a esquistossomose, Tabuas e Estreito de Miralta, pertencentes ao município de Montes Claros, região norte de Minas Gerais, empregando-se duas técnicas parasitológicas e dois ensaios moleculares para o diagnóstico da esquistossomose mansoni. Uma amostra fecal foi obtida de todos participantes e examinada utilizando a técnica de Kato-Katz (24 lâminas = 1000 mg) e a técnica do Gradiente Salínico, utilizando duas porções de 500 mg, totalizando 1000 mg de fezes. Além disso, os ensaios de PCR-ELISA e qPCR foram realizados em DNA extraído de 1000 mg de fezes. Os resultados obtidos pelas diferentes técnicas foram analisados individualmente e comparativamente entre eles. Todos os indivíduos que apresentaram ovos de Schistosoma mansoni ou outros helmintos foram tratados com praziquantel ou albendazol, respectivamente. Para avaliação de cura após o tratamento, amostras de fezes dos indivíduos positivos para S. mansoni, foram coletadas 30, 90 e 180 dias após o tratamento, e examinadas pelas técnicas parasitológicas e pelos ensaios moleculares...

Evaluation of the use of C-terminal part of the Schistosoma mansoni 200kDa tegumental protein in schistosomiasis diagnosis and vaccine formulation.

Schistosoma mansoni tegument is involved in essential functions for parasite survival and represents a target for screening candidates for vaccine and diagnosis. Our group using reverse vaccinology selected six candidates, previously demonstrated by proteomics studies to be expressed in the parasite tegument, among them was Sm200. In this work we have cloned and expressed a recombinant form of Sm200 C-terminal (1069-1520) region. The efficacy of rSm200 (1069-1520) in the diagnosis of schistosomiasis and in the formulation of a vaccine against S. mansoni was assessed respectively in an ELISA based diagnostic assay and immunization protocols in mice. Significant differences between non-infected and acutely infected or chronically infected animals were observed and no cross-recognition was observed with sera from Ascaris suum or Ancylostoma ceylanicum infected mice. rSm200-ELISA test could also discriminate infected individuals from healthy donors not living in endemic area for schistosomiasis but failed to discriminate between individuals from a low endemic area for schistosomiasis known to have positive or negative stools after examination. Recombinant Sm200 also failed to induce protection against schistosomiasis, demonstrating that the C-terminal part of Sm200 is unable to induce protective immune response in mice. Therefore rSm200 (1069-1520)-ELISA represents an important tool to be used in the diagnosis of schistosomiasis.

Cluster randomised trial to evaluate the effectiveness of a vaccine against cutaneous leishmaniasis in the Caratinga microregion, south-east Brazil.

BACKGROUND: The eco-epidemiological complexity of American cutaneous leishmaniasis (ACL) has made it difficult to devise an efficient strategy for management of the disease, and development of an effective vaccine remains the most promising approach. The objective of the study was to determine the reduction in incidence of ACL following intramuscular administration of two doses of a killed Leishmania (Leishmania) amazonensis vaccine. METHODS: A cluster randomised trial was conducted from 2002 to 2011 in 108 localities in an endemic area of southeast Brazil. Communities were stratified according to population size, and randomly allocated to receive vaccine (n = 50) or placebo (n = 58). The post-vaccination ACL incidence rates in the two groups were compared through covariance analysis. RESULTS: A cyclic fluctuation in the number of cases recorded during the 18-year pre-vaccination period was similar in both groups. Following the vaccination campaign, a significant reduction in the number of cases of ACL was observed in the vaccine group compared with the placebo group. This group also included the individuals who refused to participate in the trial. CONCLUSION: This study demonstrated that the vaccine has been able to confer protection against ACL up to the present time. It is necessary to continue epidemiological surveillance to determine the duration of the vaccine's effectiveness.

Evaluation of two coproscopic techniques for the diagnosis of schistosomiasis in a low-transmission area in the state of Minas Gerais, Brazil.

This population study, which evaluated two parasitological methods for the diagnosis of schistosomiasis mansoni, was performed in a low-transmission area in Pedra Preta, Montes Claros, Minas Gerais, Brazil. A total of 201 inhabitants of the rural area participated in this research. Four stool samples were obtained from all participants and analysed using the Kato-Katz method (18 slides) and a commercial test, the TF-Test®, which was performed quantitatively. The data were analysed to determine prevalence, the sensitivity of the diagnostic methods, the worm burden and the definition of the "gold standard", which was obtained by totalling the results of all samples examined using the Kato-Katz technique and the TF-Test®. The results showed that the prevalence obtained from the examination of one Kato-Katz slide (the methodology adopted by the Brazilian control programme) was 8% compared to 35.8% from the "gold standard", which was a 4.5-fold difference. This result indicates that the prevalence of schistosomiasis in so-called low-transmission areas is significantly underestimated.

Evaluation of two coproscopic techniques for the diagnosis of schistosomiasis in a low-transmission area in the state of Minas Gerais, Brazil

This population study, which evaluated two parasitological methods for the diagnosis of schistosomiasis mansoni, was performed in a low-transmission area in Pedra Preta, Montes Claros, Minas Gerais, Brazil. A total of 201 inhabitants of the rural area participated in this research. Four stool samples were obtained from all participants and analysed using the Kato-Katz method (18 slides) and a commercial test, the TF-Test®, which was performed quantitatively. The data were analysed to determine prevalence, the sensitivity of the diagnostic methods, the worm burden and the definition of the "gold standard", which was obtained by totalling the results of all samples examined using the Kato-Katz technique and the TF-Test®. The results showed that the prevalence obtained from the examination of one Kato-Katz slide (the methodology adopted by the Brazilian control programme) was 8 percent compared to 35.8 percent from the "gold standard", which was a 4.5-fold difference. This result indicates that the prevalence of schistosomiasis in so-called low-transmission areas is significantly underestimated.

Avaliação de métodos diagnósticos para Esquistossomose mansoni em uma área de baixa endemicidade no município de Montes Claros, Minas Gerais, Brasil / Evaluation of diagnostic methods for Schistosomiasis mansoni in a low endemic area in the city of Montes Claros, Minas Gerais, Brazil

Este estudo populacional, baseado na avaliação de dois métodos parasitológicos e um método molecular para o diagnóstico da esquistossomose mansoni foi realizado numa área de baixa transmissão na localidade de Pedra Preta, Montes Claros- MG. Um total de 201 pessoas participou desta pesquisa, todas moradoras da área rural desta localidade. Quatro amostras de fezes foram obtidas de todos participantes e analisadas utilizando o método Kato-Katz (12 lâminas da primeira, duas da segunda, terceira e quarta amostra, totalizando 18 lâminas) e o método parasitológico comercial, TF-Test®, o qual foi realizado de forma quantitativa. Além disso, a técnica de PCR-ELISA foi aplicada em 500 mg de fezes na primeira amostra. Os resultados foram analisados comparativamente ao método de Kato-Katz. Todos os positivos para S. mansoni foram tratados com praziquantel e os positivos para os outros helmintos tratados com albendazol. Para avaliação de cura após o tratamento, os positivos foram acompanhados 30, 90 e 180 dias após o tratamento, pelas duas técnicas parasitológicas. A análise dos dados envolveu determinação da prevalência, sensibilidade dos métodos diagnósticos, carga parasitária e definição de um “Padrão Ouro”, consistindo da soma de todas as amostras e lâminas examinadas pelo método de Kato-Katz e pelo método de TF-Test®.

Os resultados mostraram na comparação da prevalência obtida com uma única lâmina pelo método de Kato-Katz (metodologia adotada pelos programas de controle da doença no Brasil) e com o “Padrão Ouro”, um aumento da taxa de positividade de 8,0% para 35,8% na população, ou seja, um aumento de 4,5 vezes neste índice. Isto indica que a prevalência da esquistossomose obtida com uma lâmina de Kato-Katz, está sendo significativamente subestimada em áreas consideradas de baixa transmissão. O método de PCR-ELISA detectou 36 (18,0%) positivos, um número maior que o obtido por 12 lâminas de Kato-Katz que identificou 29 (14,4%), examinando fezes da mesma amostra. Assim, a combinação de metodologias que revelem resultados mais próximos da prevalência real da esquistossomose se torna de extrema importância em inquéritos epidemiológicos que visam à interrupção da transmissão. Em nosso estudo a taxa de reinfecção após o tratamento foi muito baixa (1,5%), o que demonstra que uma prospecção da infecção intensa é mais efetiva e pode prevenir sucessivos tratamentos.