Browsing by Author "Siqueira, Liliane Maria Vidal"

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    Cluster randomised trial to evaluate the effectiveness of a vaccine against cutaneous leishmaniasis in the Caratinga microregion, south-east Brazil.
    (2013) Mayrink, Wilson; Mendes, Alekson Mendonça; Paula, Jair Cecílio de; Siqueira, Liliane Maria Vidal; Marrocos, Simone de Resende; Dias, Edelberto Santos; Andrade, Hélida Monteiro de; Coelho, George Luiz Lins Machado
    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.
  • No Thumbnail Available
    Item
    Diagnosis of Schistosoma mansoni infections : what are the choices in Brazilian low-endemic areas?
    (2019) Moraes, Vanessa Silva; Shollenberger, Lisa Marie; Siqueira, Liliane Maria Vidal; Borges, William de Castro; Harn, Donald A.; Grenfell, Rafaella Fortini Queiroz; Rabello, Ana Lúcia Teles; Coelho, Paulo Marcos Zech
    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.
  • No Thumbnail Available
    Item
    Prevalence of schistosomiasis mansoni in indigenous Maxakali villages, Minas Gerais, Brazil.
    (2018) Nacife, Maria Beatriz Pena e Silva Leite; Siqueira, Liliane Maria Vidal; Martins, Rafael; Vianna, Valeska Natiely; Barbosa, Keila Furbino; Masioli, Cássio Zumerle; Silva, Jaime Costa da; Coelho, George Luiz Lins Machado
    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.
  • No Thumbnail Available
    Item
    Prevalência das infecções parasitárias intestinais em aldeias da etnia indígena Maxakali, Minas Gerais, Brasil.
    (2019) Nacife, Maria Beatriz Pena e Silva Leite; Coelho, George Luiz Lins Machado; Siqueira, Liliane Maria Vidal; Katz, Naftale; Coelho, Paulo Marcos Zech; Coelho, George Luiz Lins Machado
    A prevalência de parasitas intestinais é reconhecidamente elevada entre populações ameríndias e há sérias desigualdades no que se refere à saúde e à assistência de saúde das populações indígenas no Brasil. A etnia Maxakali, localizada na região nordeste de Minas Gerais em fronteira com o sul da Bahia, é um grupo indígena que sobreviveu ao extermínio e até hoje preservam muitos de seus aspectos culturais. Possuem hábitos como andar descalços, viver de forma aglomerada, deixar expostos no ambiente os alimentos, defecar no chão e nas coleções hídricas, dentre outros, que propiciam a transmissão de parasitos intestinais. Além disso, são seminômades o que dificulta a implementação de medidas de saneamento pelos órgãos competentes e a determinação da real prevalência desses parasitos intestinais. Desta forma estudos epidemiológicos nesta área se fazem necessários para que medidas preventivas e de controle sejam implementadas, podendo desta forma melhorar a qualidade de vida destes povos. As parasitoses intestinais são umas das principais causas de morbimortalidade nestes índios. Objetivo: O objetivo deste estudo foi descrever o perfil epidemiológico da esquistossomose e de outras infecções parasitárias intestinais em indivíduos que vivem nos polos base Água Boa e Pradinho, pertencentes à etnia Maxakali. Materiais e métodos: Os exames parasitológicos foram realizados pelas técnicas de Kato-Katz (uma lâmina de uma amostra) e TF-Test® (três lâminas de uma amostra). Um total de 545 amostras foram analisadas, correspondendo a quantidade de indivíduos que completaram as duas técnicas diagnósticas. Resultados: Foi encontrada uma prevalência de 84,2% para helmintos, sendo a maior positividade obtida para infecção por ancilostomídeos (59,3%), seguida por uma taxa de 51,9% para Schistosoma mansoni, de 13,9% para Hymenolepis nana, 3,9% para Trichuris trichiura, 0,7% para Taenia sp., detectados pela combinação das duas técnicas diagnósticas. Ascaris lumbricoides foi detectado apenas pela técnica de Kato-Katz com uma taxa de 0,6%, Strongyloides stercoralis e Enterobius vermicularis foram detectados apenas pela técnica de TF-Test®, apresentando positividade de 13,0% e 0,4%, respectivamente. Considerando os protozoários intestinais, foi encontrada uma prevalência de 84,8%, dos quais 28,3% eram patogênicos, 16,1% for Entamoeba histolytica/dispar e 15,2% por Giardia duodenalis. Dentre os protozoários não patogênicos, as taxas de positividade foram de 74,5% para Entamoeba coli, 56,7% para Endolimax nana e 29,9% para Iodamoeba butschii. Em relação ao diagnóstico da esquistossomose mansoni, a avaliação do desempenho da técnica de TF-Test® comparado a técnica de Kato-Katz demonstrou uma taxa de positividade pelo Kato-Katz de 45,7%, e pelo TF-Test® de 33,2%, e combinando as duas técnicas a positividade foi de 51,9%. A amplitude da carga parasitária foi de 24 a 4.056 ovos por grama de fezes (opg), com uma média geométrica de 139 opg. A sensibilidade, especificidade e acurácia pelo TF-Test® em relação ao Kato-Katz foram de 59,0%, 88,5%, e 75,0%, respectivamente. A concordância entre as duas técnicas foi moderada (k = 0,486), conforme determinado pelo índice kappa. Conclusão: A combinação de um método quantitativo e qualitativo realizado com apenas uma amostra fecal foi eficaz para a detecção de uma maior prevalência de S. mansoni e outros helmintos. A alta prevalência de parasitos intestinais pode ser atribuída à falta de infraestrutura sanitária, aos hábitos de higiene propícios à transmissão, às condições ambientais e também à alta densidade de hospedeiros intermediários, este último especificamente para a infecção da esquistossomose. Isso indica a necessidade da implementação de medidas de controle como saneamento básico, educação em saúde, além do tratamento em massa.
  • No Thumbnail Available
    Item
    Serological proteomic screening and evaluation of a recombinant egg antigen for the diagnosis of low-intensity Schistosoma mansoni infections in endemic area in Brazil.
    (2019) Moraes, Vanessa Silva; Shollenberger, Lisa Marie; Borges, William Castro; Rabello, Ana Lucia Teles; Harn, Donald A.; Medeiros, Lia Carolina Soares; Jeremias, Wander de Jesus; Siqueira, Liliane Maria Vidal; Pereira, Caroline Stephane Salviano; Pedrosa, Maria Luysa Camargos; Almeida, Nathalie Bonatti Franco; Almeida, Aureo; Lambertucci, Jose Roberto; Carneiro, Nídia Francisca de Figueiredo; Coelho, Paulo Marcos Zech; Grenfell, Rafaella Fortini Queiroz
    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 schisto- some-specific immune responses in hopes of developing sensitive and specific new meth- ods 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.
  • No Thumbnail Available
    Item
    Serological proteomic screening and evaluation of a recombinant egg antigen for the diagnosis of low-intensity Schistosoma mansoni infections in endemic area in Brazil.
    (2019) Moraes, Vanessa Silva; Shollenberger, Lisa Marie; Borges, William de Castro; Rabello, Ana Lúcia Teles; Harn, Donald A.; Medeiros, Lia Carolina Almeida Soares; Jeremias, Wander de Jesus; Siqueira, Liliane Maria Vidal; Pereira, Caroline Stephane Salviano; Pedrosa, Maria Luysa de Camargos; Almeida, Nathalie Bonatti Franco; Oliveira, Áureo Almeida de; Lambertucci, José Roberto; Carneiro, Nídia Francisca de Figueiredo; Coelho, Paulo Marcos Zech; Grenfell, Rafaella Fortini Queiroz
    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.