SerumCovid database: Description and preliminary analysis of serological COVID-19 diagnosis in healthcare workers.

Serological databases represent an important source of information to perceive COVID-19 impact on health professionals involved in combating the disease. This paper describes SerumCovid, a COVID-19 serological database focused on the diagnosis of health professionals, providing a preliminary analysis to contribute to the understanding of the antibody response to the SARS-CoV-2. The study population comprises 321 samples from 236 healthcare and frontline workers fighting COVID-19 in Vitória de Santo Antão, Brazil. Samples were collected from at least six days of symptoms to more than 100 days. The used immunoenzymatic assays were Euroimmun Anti-SARS-CoV-2 ELISA IgG and IgA. The most common gender in SerumCovid is female, while the most common age group is between 30 and 39 years old. However, no statistical differences were observed in either genders or age categories. The most reported symptoms were fatigue, headaches, and myalgia. Still, some subjects presented positive results for IgA after 130 days. Based on a temporal analysis, we have not identified general patterns as subjects presented high and low values of IgA and IgG with different evolution trends. Unexpectedly, for subjects with both serological tests, the outcome of IgA and IgG tests were the same (either positive or negative) for more than 80% of the samples. Therefore, SerumCovid helps better understand how COVID-19 affected healthcare and frontline workers, which increases knowledge about the infection and enables direct prevention actions.

Perspectives of a school teacher and teacher educators teaching during the COVID-19 situation: between insiders / Perspectivas de um professor escolar e professores universitários sobre ensinar durante a pandemia do COVID-19: Entre olhares internos / Perspectivas de un maestro y docentes sobre la situación del COVID-19: Entre perspectivas internas

This article considers the lived challenges facing three educators as they adapt, plan, and teach online lessons as a response to the Coronavirus disease. The closure of schools has forced many educators into new and uncertain territory and practices. Teaching online has been challenging in different terms and has also forced a deeper reflection on the nature of education. A self-study methodology was used to analyse the perceptions and feelings of the participants as a result of the Covid-19 pandemic. In conclusion, migrating quickly to a virtual environment deeply challenges educators' teaching praxis beyond their technical proficiency and includes the ability to be coherent with their deeper beliefs, values, theoretical approaches, and practices as educators.

Este artigo considera os desafios enfrentados por educadores ao se adaptar, planejar e ministrar aulas online em resposta ao novo cenário gerado pelo Coronavírus. O fechamento de escolas forçou muitos educadores a territórios e práticas novas e incertas. A educação remota tem sido um desafio em diferentes termos e tem gerado reflexões sobre a natureza da educação. A metodologia auto-estudo foi utilizada para analisar as percepções e sentimentos dos participantes em decorrência desta pandemia. A rápida migração para um ambiente virtual desafia profundamente a práxis pedagógica dos educadores, além de sua proficiência técnica, incluindo a capacidade de ser coerentes com suas crenças, valores, abordagens teóricas e práticas.

Este artículo considera los desafíos que enfrentan los educadores a adaptarse para planificar e impartir clases en línea en respuesta al nuevo escenario generado por el virus Covid-19. Los cierres de escuelas han obligado a muchos educadores a vivir en territorios y prácticas nuevas e inciertas. La educación y las tecnologías para la enseñanza digital ha sido desafiante y ha generado reflexiones sobre la educación. La metodología de autoestudio se utilizó para analizar las percepciones y sentimientos de los participantes debido a la pandemia. La rápida migración a un entorno virtual desafía profundamente la praxis pedagógica de los educadores, además de su competencia técnica, incluida la capacidad de ser coherentes con sus creencias, valores, enfoques teóricos y prácticos.

Google sites como ferramenta de ensino de educação física a distância em tempos de covid-19: pedagogia, estratégias, reflexões e barreiras de um professor / Google sites como herramienta para la enseñanza de educación física a distancia en tiempos de covid-19: pedagogía, estrategias, reflexiones y barreras de un profesor / Teaching online physical education during social distancing using google sites: pedagogy, strategies, reflections and barriers of a teacher

Resumo A covid-19 resultou na implementação de medidas de distanciamento social e fechamento de escolas no mundo. Este estudo explora alguns dos impactos, tais como escolhas pedagógicas, reflexões e barreiras do professor quando ele repentinamente mudou para um ambiente de ensino online e teve que ministrar aulas de Educação Física (EF) com o uso da tecnologia (Google Sites). A metodologia do autoestudo com análise temática foi utilizada para investigar as experiências do autor principal. Achados destacam como o professor teve que encontrar novas formas de ensino online, fazendo com que os alunos não estivessem exclusivamente em frente à tela, e atendesse as características sociais e dinâmicas da EF. Finalmente, as experiências e o processo de reflexão demonstraram a necessidade de ser coerente com as escolhas pedagógicas e abordagens teóricas e práticas como professor. Este artigo contribui para futuras formas de ensino de EF online, ao compreender a práxis de um professor.

Resumen El Covid-19 ha llevado a la implementación de medidas de distancia social y al cierre de escuelas en todo el mundo. Este estudio explora algunos de los impactos, como opciones pedagógicas, reflexiones y barreras del profesor cuando este cambia repentinamente a un entorno de enseñanza online, con el uso de la tecnología (Google Sites). La metodología de self-study con análisis temático se utilizó para investigar las experiencias del autor principal. Los resultados destacan que el profesor tuvo que encontrar nuevas formas de enseñanza online, logrando que los alumnos no estuvieran exclusivamente frente a la pantalla, y cumplir con las características sociales y dinámicas de la Educación Física. Finalmente, las experiencias y la reflexión demostraron la necesidad de ser coherente, como profesor, con las elecciones pedagógicas y los enfoques teóricos y prácticos. Este artículo contribuye con las futuras formas de enseñanza de la Educación Física online mediante la comprensión de la praxis de un profesor.

Abstract Covid-19 has resulted in the implementation of social distancing measures and school closures worldwide. This study explores some of the impacts, such as pedagogies, teaching strategies, reflections, and barriers of the teacher as he suddenly moved to an online teaching environment and taught PE lessons with the use of technology (Google Sites). A self-study methodology with thematic analysis was used to investigate the lead author's experiences. Findings and discussions highlight how the teacher had to find new forms of teaching online, ways of making the students not be exclusively in front of the screen, and simultaneously be concordant with the social and dynamic characteristics of PE. Ultimately, the experiences and the process of reflection demonstrated the need to be coherent with teaching beliefs, assumptions, theoretical approaches and practices as a teacher. This article foregrounds and contributes to future ways of teaching PE online by understanding one teacher's praxis.

Onset and duration of symptoms of loss of smell/taste in patients with COVID-19: A systematic review.

OBJECTIVE: The aim of the study was to conduct a systematic review of the literature to investigate the time of onset and duration of symptoms of loss of smell and taste in patients diagnosed with COVID-19. METHODS: Two independent authors performed a systematic review of the Medline/PubMed, SCOPUS, COCHRANE, Lilacs and Web of Science electronic databases. The time of onset and duration of symptoms were considered primary outcomes. The sex and age of individuals, the geographical location of the study, the prevalence of symptoms, other associated symptoms, associated comorbidities, and the impact on quality of life and eating habits were considered secondary outcomes. RESULTS: Our search generated 17 articles. Many of the studies reported that the onset of anosmia and ageusia occurred 4 to 5 days after the manifestation of other symptoms of the infection and that these symptoms started to disappear after one week, with more significant improvements in the first two weeks. CONCLUSION: The present study concludes that the onset of symptoms of loss of smell and taste, associated with COVID-19, occurs 4 to 5 days after other symptoms, and that these symptoms last from 7 to 14 days. Findings, however, varied and there is therefore a need for further studies to clarify the occurrence of these symptoms. This would help to provide early diagnosis and reduce contagion by the virus.

Plano de parto como instrumento das boas práticas no parto e nascimento: revisão integrativa / Plan de parto como instrumento de buenas prácticas en el trabajo de parto y en el parto: una revisión integradora / Birth plan as an instrument of good practices in delivery and birth: an integrative review

Objetivo analisar as evidências disponíveis sobre as principais contribuições do plano de parto como instrumento das boas práticas obstétricas no processo de parto e nascimento em ambiente hospitalar. Método revisão integrativa com 12 artigos publicados entre 2013 e 2018 nas bases de dados MEDLINE, Biblioteca Virtual de Saúde, LILACS, SciELO e PubMed, utilizando trabalhos originais, reflexão, atualização e relato de experiência, completos e disponíveis na íntegra. Resultados observou-se a importância do plano de parto para estimular as boas práticas obstétricas, permitir maior autonomia e liberdade de escolha das mulheres, contribuir para um atendimento qualificado e humanizado, facilitar a confiança da mulher com a equipe, além de favorecer maior satisfação com o parto, comunicação com os profissionais envolvidos e propiciar resultados maternos/neonatais mais satisfatórios. Conclusão comprovou-se que o plano de parto é um instrumento que propicia boas práticas obstétricas no processo de parto e nascimento em ambiente hospitalar.

Objetivo analizar las evidencias disponibles sobre las principales contribuciones del plan de parto como instrumento de las buenas prácticas obstétricas en el proceso de parto y nacimiento en el entorno de un hospital. Método revisión integradora con 12 artículos publicados entre 2013 y 2018 en las siguientes bases de datos: MEDLINE, Biblioteca Virtual de Saúde, LILACS, SciELO y PubMed, utilizando trabajos originales, de reflexión, de actualización y reporte de experiencias, completos y disponibles en forma íntegra. Resultados se observó la importancia del plan de parto para estimular las buenas prácticas obstétricas, permitir mayor autonomía y libertad de elección de las mujeres, contribuir a una asistencia calificada y humanizada, facilitar que la mujer confíe en el equipo médico, además de favorecer una mayor satisfacción con el parto, la comunicación con los profesionales participantes, y propiciar resultados maternos/neonatales más satisfactorios. Conclusión se comprobó que el plan de parto es un instrumento que propicia buenas prácticas obstétricas en el proceso de parto y nacimiento en un ambiente de hospital.

Objective to analyze the available evidence on the main contributions of the birth plan as an instrument of good obstetric practices in the process of delivery and birth in a hospital environment. Method an integrative review with 12 articles published between 2013 and 2018 in the MEDLINE, Virtual Health Library, LILACS, SciELO and PubMed databases, using full and complete original works, reflection, update and experience report. Results the importance of the birth plan importance was observed to encourage good obstetric practices, allow greater autonomy and freedom of women's choice, contribute to a qualified and humanized care, facilitate women's trust with the team, and promote greater satisfaction with childbirth, communication with the involved professionals and provide more satisfactory maternal/neonatal results. Conclusion it was proved that the birth plan is an instrument that provides good obstetric practices in the process of delivery and birth in a hospital environment.

Isolation of Actinobacillus seminis from a goat with clinical epididymo-orchitis in Brazil.

The present study reports the first isolation of Actinobacillus seminis from a goat in Brazil. A four-year-old Moxotó breeding goat in a flock of 70 goats and 65 sheep reared together in the county of Patos, semiarid region of Northeastern Brazil, showed clinical signs of unilateral orchitis and epididymitis. Diagnosis of A. seminis infection was confirmed by association of clinical findings, bacterial isolation and 16S rRNA gene sequencing. This result suggests that A. seminis may be an additional cause of infertility in goats, and that sheep may be the source of infection because the mixed farming system allows the contact between sheep and goats in the semiarid region of Northeastern Brazil.

Isolation of Actinobacillus seminis from a goat with clinical epididymo-orchitis in Brazil

The present study reports the first isolation of Actinobacillus seminis from a goat in Brazil. A four-year-old Moxotó breeding goat in a flock of 70 goats and 65 sheep reared together in the county of Patos, semiarid region of Northeastern Brazil, showed clinical signs of unilateral orchitis and epididymitis. Diagnosis of A. seminis infection was confirmed by association of clinical findings, bacterial isolation and 16S rRNA gene sequencing. This result suggests that A. seminis may be an additional cause of infertility in goats, and that sheep may be the source of infection because the mixed farming system allows the contact between sheep and goats in the semiarid region of Northeastern Brazil.

Detecção de Toxoplasma gondii em órgãos do sistema reprodutivo de carneiros naturalmente infectados no Brasil / Detection of Toxoplasma gondii in the reproductive organs of rams in Brazil

Objetivou-se com esse estudo detectar o DNA genômico de T. gondii em amostras de testículo e epidídimo de ovinos comercializados em abatedouros do Estado de Pernambuco Região Nordeste do Brasil. Foram coletadas 50 amostras de soro sanguíneo, 50 amostras de testículos e 50 de epidídimos. Para a triagem dos animais foi utilizada a técnica de Imunofluorescência Indireta (RIFI) e posteriormente empregou-se a Reação em Cadeia da Polimerase (PCR) nos animais positivos na sorologia. Observou-se 24% (12/50) dos animais positivos na RIFI e o DNA genômico foi detectado no epidídimo em 8,3% (1/12) das amostras. A identidade molecular dos produtos amplificados foi confirmada por sequenciamento. Relata-se a primeira ocorrência da presença do DNA de T. gondii em órgãos do sistema reprodutivo de carneiros naturalmente infectados no Brasil.

The aim of the study was to detect genomic DNA of Toxoplasma gondii in testicle and epididymis samples from rams sold in abattoirs in the state of Pernambuco, Northeast Brazil. Fifty (50) blood serum samples were collected, as well as 50 testicle and epididymis samples. Indirect Immunofluorescence (IIF) was used during screening of the rams. The Polymerase Chain Reaction (PCR) was used with animals that were positive in serology. Our results confirmed that 24% (12/50) of the rams were positive in IIF. Genomic DNA was detected in the epididymis at 8.3% (1/12) of the animals. The molecular identity of the amplified products was confirmed through sequencing. This paper reports the first occurrence of T. gondii DNA in the reproductive organs of naturally infected rams in Brazil.

Complement factor H gene (CFH) polymorphisms C-257T, G257A and haplotypes are associated with protection against severe dengue phenotype, possible related with high CFH expression.

Four genetic polymorphisms located at the promoter (C-257T) and coding regions of CFH gene (exon 2 G257A, exon 14 A2089G and exon 19 G2881T) were investigated in 121 dengue patients (DENV-3) in order to assess the relationship between allele/haplotypes variants and clinical outcomes. A statistical value was found between the CFH-257T allele (TT/TC genotypes) and reduced susceptibility to severe dengue (SD). Statistical associations indicate that individuals bearing a T allele presented significantly higher protein levels in plasma. The -257T variant is located within a NF-κB binding site, suggesting that this variant might have effect on the ability of the CFH gene to respond to signals via the NF-κB pathway. The G257A allelic variant showed significant protection against severe dengue. When CFH haplotypes effect was considered, the ancestral CG/CG promoter-exon 2 SNP genotype showed significant risk to SD either in a general comparison (ancestral × all variant genotypes), as well as in individual genotypes comparison (ancestral × each variant genotype), where the most prevalent effect was observed in the CG/CG × CA/TG comparison. These findings support the involvement of -257T, 257A allele variants and haplotypes on severe dengue phenotype protection, related with high basal CFH expression.

Lentivírus em caprinos leiteiros do semiárido paraibano: prevalência de anticorpos, fatores de risco e detecção molecular / Lentivirus in dairy goats from the semiarid region of Paraiba state: seroprevalence, risk factors and molecular detection

Os objetivos do presente trabalho foram determinar a prevalência de caprinos leiteiros soropositivos para a infecção por Lentivirus de pequenos ruminantes no semiárido do Estado da Paraíba, Nordeste do Brasil, identificar fatores de risco associados à prevalência de rebanhos positivos, e realizar a detecção molecular do agente. Foram utilizadas 1047 cabras leiteiras de 110 propriedades selecionadas aleatoriamente no Município de Monteiro, Estado da Paraíba, no período de março de 2009 a dezembro de 2011. Para o diagnóstico da infecção por Lentivirus, foi utilizado o teste de imunodifusão em gel de ágar (AGID). Um ano após foi realizada nova sorologia, e PCR em tempo real foi aplicada em amostras de sangue e leite de 48 cabras procedentes de quatro propriedades com animais soropositivos. As prevalências de propriedades positivas e de animais soropositivos na AGID foram 44,6% (IC 95% = 35,1% - 54,3%) e 8,1% (IC 95% = 5,6% - 16,8%), respectivamente. Realizar corte e desinfecção de umbigo (odds ratio = 2,44; p = 0,048) e condições de aglomeração de animais (odds ratio = 3,45; p = 0,048) foram associadas com a prevalência de propriedades positivas. Um ano após a realização do inquérito sorológico, foi verificada a permanência de animais infectados, detectados por PCR em tempo real a partir de amostras de sangue e leite. A PCR em tempo real das amostras de leucócitos circulantes apresentou boa performance, com sensibilidade de 100%, especificidade de 92,86%, concordância de 93,75% e indicador Kappa de 0,765. Sugere-se que seja realizado um trabalho de educação sanitária junto aos produtores sobre medidas de prevenção com o objetivo de reduzir a disseminação da infecção nos rebanhos.

The aims of this study were to determine the seroprevalence of infection by ruminants Lentivirus in dairy goats in the semiarid of the Paraiba State, Northeastern Brazil, to identify risk factors associated with the herd-level prevalence and to perform molecular detection of the agent. A total of 1,047 dairy goats from 110 herds were randomly selected from the county of Monteiro, Paraiba State, and serum samples were collected from March 2009 to December 2011. For the diagnosis of Lentivirus infection, the agar gel immunodiffusion test (AGID) was used. One year after that a new serology was performed and the real-time PCR assay was applied in blood and milk samples from 48 goats from four herds with seropositive animals. Prevalence of positive herds and seropositive animals at AGID were 44.6% (95% CI=35.1-54.3%) and 8.1% (95% CI =5.6-16.8%), respectively. Umbilical cord cutting and disinfection (odds ratio = 2.44; p = 0.048) and conditions of animal agglomeration (odds ratio=3.45; p=0.048) were associated with herd-level prevalence. One year after the serological profile, the permanence of infected animals detected by real-time PCR in blood and milk samples was verified. Real-time PCR using white blood cells had a good performance, with sensitivity of 100%, specificity of 92.86%, concordance of 93.75% and Kappa index of 0.765. It was suggested to teach sanitary measures to the herd owners in order to encourage them to adopt prevention measures aiming to reduce the spread of the infection in the herds.

Classification of dengue fever patients based on gene expression data using support vector machines.

BACKGROUND: Symptomatic infection by dengue virus (DENV) can range from dengue fever (DF) to dengue haemorrhagic fever (DHF), however, the determinants of DF or DHF progression are not completely understood. It is hypothesised that host innate immune response factors are involved in modulating the disease outcome and the expression levels of genes involved in this response could be used as early prognostic markers for disease severity. METHODOLOGY/PRINCIPAL FINDINGS: mRNA expression levels of genes involved in DENV innate immune responses were measured using quantitative real time PCR (qPCR). Here, we present a novel application of the support vector machines (SVM) algorithm to analyze the expression pattern of 12 genes in peripheral blood mononuclear cells (PBMCs) of 28 dengue patients (13 DHF and 15 DF) during acute viral infection. The SVM model was trained using gene expression data of these genes and achieved the highest accuracy of approximately 85% with leave-one-out cross-validation. Through selective removal of gene expression data from the SVM model, we have identified seven genes (MYD88, TLR7, TLR3, MDA5, IRF3, IFN-alpha and CLEC5A) that may be central in differentiating DF patients from DHF, with MYD88 and TLR7 observed to be the most important. Though the individual removal of expression data of five other genes had no impact on the overall accuracy, a significant combined role was observed when the SVM model of the two main genes (MYD88 and TLR7) was re-trained to include the five genes, increasing the overall accuracy to approximately 96%. CONCLUSIONS/SIGNIFICANCE: Here, we present a novel use of the SVM algorithm to classify DF and DHF patients, as well as to elucidate the significance of the various genes involved. It was observed that seven genes are critical in classifying DF and DHF patients: TLR3, MDA5, IRF3, IFN-alpha, CLEC5A, and the two most important MYD88 and TLR7. While these preliminary results are promising, further experimental investigation is necessary to validate their specific roles in dengue disease.

International course on emerging viruses in the Amazon region.

The international course Emerging Viruses: Global Approaches and Specificities of the Amazon Region was held in Porto Velho, Rondonia, Brazil, November 17-December 7, 2007. Organized as part of the Amsud-Pasteur research collaboration program (sponsored by Institut Pasteur), the course was held there primarily because Rondonia State is located in the Amazon region, a particular environment in which new viruses could emerge as a consequence of ecologic changes brought about by exploration and other human activities.

Desenvolvimento e validação da detecção molecular da infecção por schistosoma mansoni em lotes de moluscos vetores para identificação de focos de transmissão / Development and validation of molecular approaches of infection by Shistosoma mansoni in vector snails to be used on identifying the transmission focus

A identificação de moluscos infectados pelo Schistosoma mansoni é de grande interesse para a saúde pública, pois representa focos de transmissão da esquistossomose. As limitações da técnica padrão-ouro para o diagnóstico de infecções pré-patentes e em larga escala faz com que os métodos moleculares sejam vistos como possíveis alternativas através da detecção de DNA do S. mansoni em lotes de moluscos vetores. A detecção de seqüências específicas de DNA por reação em cadeia da polimerase (PCR) tem confirmado ser de extremo valor para a análise genética e diagnóstico de várias doenças patogênicas infecciosas. O principal objetivo desse trabalho é desenvolver e validar a detecção molecular da infecção por S. mansoni em lotes de moluscos vetores para a identificação de focos de transmissão. Os iniciadores foram desenhados para detectar especificamente DNA de S. mansnoni e amplificam gene na subunidade pequena do rRNA. Neste trabalho foi desenvolvido PCR quantitativa em tempo real (qPCR) e validada juntamente com ensaios de PCR, nested PCR (NPCR) e nested PCR em único tubo (STNPCR). Quando comparados as duas metodologias relacionadas ao padrão-ouro e abordagens moleculares os resultados confirmaram que a NPCR, STNPCR e a qPCR são significantemente mais sensíveis (p 0.05) que a PCR e que a técnica padrão-ouro. Significante relação foi observada entre os resultados da qPCR e a liberação de cercarias. As ferramentas moleculares desenvolvidas neste trabalho, se utilizadas em lotes de moluscos, podem ser consideradas alternativas e/ou complementares à técnica convencional para identificar focos de transmissão da esquistossomose.

Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA

This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR) protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA). The efficiency was 0.99 and the correlation coefficient (R²) was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83°C). The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden) in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.

Molecular approaches for the detection of Schistosoma mansoni: possible applications in the detection of snail infection, monitoring of transmission sites, and diagnosis of human infection

The detection of specific DNA sequences by polymerase chain reaction (PCR) has proved extremely valuable for the analysis of genetic disorders and the diagnosis of a variety of infectious disease pathogens. However, the application to the detection of Schistosoma mansoni is rare, despite a recommendation of the World Health Organization that a major focus of research on schistosomiasis should be on the development and evaluation of new strategies and tools for control of the disease. In this context, a few studies were published for the detection of the parasite in snails, monitoring of cercariae in water bodies, and diagnosis of human infection. The present minireview describes sensitive and specific PCR based systems to detect S. mansoni, indicating possible applications in the detection of snail infection, monitoring of transmission sites, and diagnosis of human infection.

Development of molecular approaches for the identification of transmission sites of schistosomiasis.

Primers targeting the gene encoding the small subunit rRNA were designed to amplify DNA from Schistosoma mansoni with high specificity. Three PCR systems were developed: conventional PCR, two-step nested PCR (NPCR) and single-tube nested PCR (STNPCR). The limits of detection of parasite DNA for the conventional PCR, NPCR and STNPCR were 10 pg, 0.1 fg and 1 fg, respectively. The assays were highly specific for S. mansoni and did not recognise DNA from closely related non-schistosome trematodes. Using pools of Biomphalaria molluscs, PCR, NPCR and STNPCR were positive in 6/16 (37.5%), 15/16 (93.8%) and 13/16 (81.3%) of the tested samples, respectively, whereas the observation of cercariae shedding after exposure to light was able to detect S. mansoni infection in 6/16 (37.5%) of the pools. Thus, the molecular detection systems had a higher level of sensitivity than standard screening of intermediate hosts by cercarial shedding when DNA was purified from pools of snails collected from endemic areas. These PCR protocols have potential to be used as tools for monitoring of schistosome transmission.

Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA.

This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR) protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA). The efficiency was 0.99 and the correlation coefficient (R(2)) was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83 degrees C). The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden) in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.

Molecular approaches for the detection of Schistosoma mansoni: possible applications in the detection of snail infection, monitoring of transmission sites, and diagnosis of human infection.

The detection of specific DNA sequences by polymerase chain reaction (PCR) has proved extremely valuable for the analysis of genetic disorders and the diagnosis of a variety of infectious disease pathogens. However, the application to the detection of Schistosoma mansoni is rare, despite a recommendation of the World Health Organization that a major focus of research on schistosomiasis should be on the development and evaluation of new strategies and tools for control of the disease. In this context, a few studies were published for the detection of the parasite in snails, monitoring of cercariae in water bodies, and diagnosis of human infection. The present minireview describes sensitive and specific PCR based systems to detect S. mansoni, indicating possible applications in the detection of snail infection, monitoring of transmission sites, and diagnosis of human infection.