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

Usefulness of Environmental DNA for Surveillance and Control of Schistosomiasis: Detection and Tracking Schistosoma mansoni and Its Intermediate Host Biomphalaria glabrata in Low Endemic Areas of Minas Gerais, Brazil

Poster Session

Schistosoma mansoni: ação da lovastatina no modelo murino

Com o objetivo de avaliar a ação da lovastatina na postura do Schistosoma mansoni foram usados camundongos infectados com 100 ±10 cercárias da cepa LE. Trinta dias após a infecção, os animais foram tratados com 100, 200 e 400mg/kg de lovastatina, via oral, durante cinco dias consecutivos e sacrificados 7,15,30 ou 60 dias após o tratamento. Foram analisados: distribuição de vermes no mesentério e fígado, mortalidade de vermes no fígado, alteração do oograma, contagem de ovos no jejuno e fígado, presença de ovos intra-uterino e morfologia dos vermes dos grupos tratados e controle (animais infectados e não tratados). Diferenças estatisticamente significativas foram encontradas, na dose de 400mg/kg, entre grupos tratados e controles quando se considerou a presença de ovos no útero, a alteração do oograma, ovos nos diferentes estágios de desenvolvimento no jejuno e fígado e no comprimento do corpo dos vermes machos e fêmeas. O estudo morfológico dos vermes mostrou alterações degenerativas sendo as principais no aparelho reprodutor, com redução e alteração dos folículos vitelínicos e do ovário das fêmeas e modificações nos testículos dos machos. Os resultados apresentados levam à conclusão que a droga em estudo reduz, consideravelmente, a oviposição das fêmeas do S. mansoni, aumenta o tamanho dos vermes, provoca alterações no sistema reprodutivo de machos e fêmeas e pode ocasionar morte de parte significativa da população de vermes na dose de 400mg/kg

Enterobius vermicularis eggs in basic health unit waiting rooms and toilets in the city of New-Serrana, MG, Brazil: contributions to control.

Submitted by Nuzia Santos ([email protected]) on 2018-12-10T11:16:11Z No. of bitstreams: 1 Enterobius vermicularis eggs in basic health unit waiting.pdf: 1151266 bytes, checksum: 0bfdc5b8732c5a9a9a8f18e56dd9d174 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2018-12-10T11:19:54Z (GMT) No. of bitstreams: 1 Enterobius vermicularis eggs in basic health unit waiting.pdf: 1151266 bytes, checksum: 0bfdc5b8732c5a9a9a8f18e56dd9d174 (MD5)Made available in DSpace on 2018-12-10T11:19:55Z (GMT). No. of bitstreams: 1 Enterobius vermicularis eggs in basic health unit waiting.pdf: 1151266 bytes, checksum: 0bfdc5b8732c5a9a9a8f18e56dd9d174 (MD5) Previous issue date: 2013Universidade Estadual de Minas Gerais. Fundação Educacional de Divinópolis. Divinópolis, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Helmintologia e Malacologia Médica. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Helmintologia e Malacologia Médica. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Esquistossomose. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Leishmanioses. Belo Horizonte, MG, Brasil.Neste trabalho, avaliou-se, utilizando a técnica de Graham (1941), a presença de ovos de helmintos intestinais em amostras coletadas em objetos de cinco Unidades Básicas de Saúde (UBS) da cidade de Nova Serrana-MG. No total de oito coletas, foram amostrados, nas recepções, 40 mesas de atendimento e 40 assentos de cadeiras e, nos banheiros, 64 maçanetas internas e 64 maçanetas externas de portas. Todas as lâminas foram analisadas por microscopia óptica nos aumentos de 10X e 40X no Laboratório de Microscopia da FUNEDI/UEMG e reexaminadas no Laboratório de Helmintologia e Malacologia Médica do Centro de Pesquisas René Rachou (FIOCRUZ-Minas). Os resultados indicaram a presença de ovos de Enterobius vermicularis, em sua maioria, viáveis, sendo os percentuais de ocorrência calculados por meio de proporção simples. Na recepção, a porcentagem de contaminação foi de 25,0% nas mesas de atendimento e de 17,9% no assento das cadeiras; nos banheiros, 35,7% das maçanetas internas e 21,4% das maçanetas externas apresentaram ovos. Não foram encontrados ovos e larvas de outros helmintos, apenas grãos de pólen, fibras vegetais e esporos de fungos. Foram realizadas palestras direcionadas aos funcionários destas UBS para apresentar-lhes os resultados e discutir medidas para evitar a contaminação de pessoas que frequentam e trabalham nestes locais. Os dados evidenciaram que as salas de espera das UBS podem ser importantes veículos de dispersão e contaminação de enteroparasitos. Medidas de educação em saúde são importantes e devem ser realizadas entre os usuários e funcionários dos postos, pois levam as pessoas a conhecer o problema, mudar seus hábitos e discutir soluções para prevenção e controle desta e de outras endemias

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

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

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

Submitted by Nuzia Santos ([email protected]) on 2020-01-31T15:33:29Z No. of bitstreams: 1 Transmission control of schistosomiasis.pdf: 3308798 bytes, checksum: 1f5470d2c599e4496380006d1b88f114 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2020-01-31T15:40:29Z (GMT) No. of bitstreams: 1 Transmission control of schistosomiasis.pdf: 3308798 bytes, checksum: 1f5470d2c599e4496380006d1b88f114 (MD5)Made available in DSpace on 2020-01-31T15:40:29Z (GMT). No. of bitstreams: 1 Transmission control of schistosomiasis.pdf: 3308798 bytes, checksum: 1f5470d2c599e4496380006d1b88f114 (MD5) Previous issue date: 2019Universidade Estadual de Montes Claros. Montes Claros, MG, Brasil / Centro de Controle de Zoonoses. Montes Claros, MG, Brasil / Universidade Estadual de Montes Claros. Montes Claros, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Esquistossomose. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Esquistossomose. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Esquistossomose. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Pesquisa Clínica. Belo Horizonte, MG, Brasil.Universidade Estadual de Montes Claros. Montes Claros, MG, Brasil.Instituto Evandro Chagas. Ananindeua, PA, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Esquistossomose. Belo Horizonte, MG, Brasil.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

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