Immune reactivity to Trypanosoma cruzi chimeric proteins for Chagas disease diagnosis in immigrants living in a non-endemic setting

Chagas disease; Chimeric antigens; Trypanosoma cruziMalaltia de Chagas; Antígens quimèrics; Trypanosoma cruziEnfermedad de Chagas; Antígenos quiméricos; Trypanosoma cruziBACKGROUND: Chronic Chagas Disease (CD) diagnosis is based on serological methods employing crude, semipurified or recombinant antigens, which may result in low sensitivity or cross-reactivity. To reduce these restrictions, we developed a strategy involving use of molecules containing repetitive fragments of Trypanosoma cruzi conserved proteins. Diagnostic performance of IBMP-8.1 and IBMP-8.4 chimeric antigens (Molecular Biology Institute of Paraná - IBMP in Portuguese acronym) was assessed to diagnose T. cruzi-infected and non-infected immigrants living in Barcelona (Spain), a non-endemic setting for Chagas disease. METHODS: Reactivity of IBMP-8.1 and IBMP-8.4 was assessed using an in-house automated ELISA with 347 positive and 331 negative individuals to Chagas disease. Antigenic cross-reactivity was measured with sera samples from pregnant women with Toxoplasma gondii (n = 98) and Zika virus (n = 75) antibodies. RESULTS: The area under the curve values was 1 and 0.99 for the IBMP-8.1 and IBMP-8.4 proteins, respectively, demonstrating excellent diagnostic accuracy. The reactivity index was higher for IBMP-8.1 than IBMP-8.4 in positive samples and no significant difference in reactivity index was observed in negative samples. Sensitivity ranged from 99.4% for IBMP-8.1 to 99.1% for IBMP-8.4 and was not statistically different. Specificity for IBMP-8.1 reached 100 and 99.7% for IBMP-8.4, both nearly 100% accurate. No antigenic cross-reactivity was observed and reactivity index was similar to that for negative Chagas disease individuals. CONCLUSIONS: Our results showed an outstanding performance of IBMP-8.1 and IBMP-8.4 chimeric antigens by ELISA and suggest both chimeric antigens could also be used for Chagas disease diagnosis in immigrants living in non-endemic settings

Performance of recombinant chimeric proteins in the serological diagnosis of Trypanosoma cruzi infection in dogs.

Background: Dogs are considered sentinels in areas of Trypanosoma cruzi transmission risk to humans. ELISA is generally the method of choice for diagnosing T. cruzi exposure in dogs, but its performance substantially depends on the antigenic matrix employed. In previous studies, our group has developed four chimeric antigens (IBMP-8.1, 8.2, 8.3, and 8.4) and evaluated their potential for diagnosing T. cruzi exposure in humans. For human sera, these chimeric antigens presented superior diagnostic performances as compared to commercial tests available in Brazil, Spain, and Argentina. Therefore, in this study we have evaluated the potential of these antigenic proteins for detection of anti-T. cruzi IgG antibodies in dog sera. Methodology/Principal findings: The IBMP-ELISA assays were optimized by checkerboard titration. Subsequently, the diagnostic potential was validated through analysis of ROC curves and the performance of the tests was determined using double entry tables. Cross-reactivity was also evaluated for babesiosis, ehrlichiosis, dirofilariosis, anaplasmosis, and visceral leishmaniasis. Best performance was shown by IBMP-8.3 and IBMP-8.4, although all four antigens demonstrated a high diagnostic performance with 46 positive and 149 negative samples tested. IBMP-8.3 demonstrated 100% sensitivity, followed by IBMP-8.4 (96.7?100%), IBMP-8.2 (73.3?87.5%), and IBMP-8.1 (50?100%). The highest specificities were achieved with IBMP-8.2 (100%) and IBMP-8.4 (100%), followed by IBMP-8.3 (96.7?97.5%) and IBMP 8.1 (89.1?100%). Conclusions/Significance: The use of chimeric antigenic matrices in immunoassays for anti-T. cruzi IgG antibody detection in sera of infected dogs was shown to be a promising tool for veterinary diagnosis and epidemiological studies. The chimeric antigens used in this work allowed also to overcome the common hurdles related to serodiagnosis of T. cruzi infection, especially regarding variation of efficiency parameters according to different strains and cross-reactivity with other infectious diseases

Alterations in the lipid profiles and circulating liver enzymes in individuals infected by Schistosoma mansoni

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2019-02-01T18:03:19Z No. of bitstreams: 1 SILVA, F.L. Alterations in lipid profile...2018.pdf: 2734859 bytes, checksum: 8b8fe8385076ecbba9e7c3b334824b27 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-02-01T18:11:28Z (GMT) No. of bitstreams: 1 SILVA, F.L. Alterations in lipid profile...2018.pdf: 2734859 bytes, checksum: 8b8fe8385076ecbba9e7c3b334824b27 (MD5)Made available in DSpace on 2019-02-01T18:11:28Z (GMT). No. of bitstreams: 1 SILVA, F.L. Alterations in lipid profile...2018.pdf: 2734859 bytes, checksum: 8b8fe8385076ecbba9e7c3b334824b27 (MD5) Previous issue date: 2018Gonçalo Moniz Institute (Fiocruz-BA).Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Laboratório de Análise de Sistemas de Informações em Saúde. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório Avançado de Saúde Pública. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório de Interação Parasito-Hospedeiro e Epidemiologia. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório Avançado de Saúde Pública. Salvador, BA, Brasil.Grupo Promedica. Laboratório Datalab. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório Avançado de Saúde Pública. Salvador, BA, Brasil.Portal hypertension and periportal fibrosis commonly occur in severe Schistosoma mansoni infection. Changes in lipid profile and elevated levels of circulating liver enzymes have also been described in infected individuals. The present study sought to assess the alterations in laboratory parameters associated with liver disorder in individuals infected by S. mansoni who visited a private routine laboratory service. Levels of circulating liver enzymes (gamma-glutamyl transferase [γ-GT], aspartate transaminase [AST], alanine transaminase [ALT], and alkaline phosphatase [ALP]) and a lipid panel (total cholesterol [COL], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very low-density lipoprotein [VLDL], and triglycerides [TRI]) were evaluated in both infected and non-infected individuals and relative risk was used to measure associations. Methods: Data were collected for analysis from a total of 1,078 cases identified in 379,600 individuals who submitted samples to the Datalab Laboratory (Salvador, Bahia) between 2004 and 2008. Results: S. mansoni infection led to increased circulating levels of γ-GT in both women and men, AST (women), and ALP (men). S. mansoni infection was a protective factor against increased levels of TRI, CHO, and VLDL for individuals aged 19 years or older. The results of our analysis indicate that alterations in lipid metabolism and circulating liver enzymes in asymptomatic S. mansoni-infected individuals might be attributed to eggs lodged in the hepatic sinusoids. Conclusions: Parasitological testing for S. mansoni should be indicated in endemic areas when this pattern of alterations is detected

A Cross-Sectional Study of Entamoeba histolytica/dispar/moshkovskii Complex in Salvador, Bahia, Brazil

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2019-08-13T14:10:25Z No. of bitstreams: 1 Soares, Neci M. A Cross Sectional....pdf: 1545461 bytes, checksum: 119bffad14c5d85c075acf8a440372e1 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-08-13T14:25:12Z (GMT) No. of bitstreams: 1 Soares, Neci M. A Cross Sectional....pdf: 1545461 bytes, checksum: 119bffad14c5d85c075acf8a440372e1 (MD5)Made available in DSpace on 2019-08-13T14:25:12Z (GMT). No. of bitstreams: 1 Soares, Neci M. A Cross Sectional....pdf: 1545461 bytes, checksum: 119bffad14c5d85c075acf8a440372e1 (MD5) Previous issue date: 2019Gonçalo Moniz Institute (Fiocruz-BA).Federal University of Bahia. Pharmacy College. Salvador, BA, Brazil.Federal University of Bahia. Pharmacy College. Salvador, BA, Brazil.Federal University of Bahia. Pharmacy College. Salvador, BA, Brazil.Federal University of Bahia. Pharmacy College. Salvador, BA, Brazil.Faculty of Technology and Sciences of Bahia. Salvador, BA, Brazil.Federal University of Bahia. Pharmacy College. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Laboratório Avançado de Saúde Pública. Salvador, BA, Brasil.Epidemiological studies on species-specific Entamoeba infections are scarce due to the morphological similarity of pathogenic Entamoeba histolytica and nonpathogenic E. dispar and E. moshkovskii. The diagnosis of E. histolytica is frequently based on coproantigen (E. histolytica-Gal/GalNAc lectin specific) detection by immunoassays. However, specific E. histolytica-lectin is not expressed in cysts, which are eliminated by asymptomatic individuals leading to false-negative results and an underestimation of amebiasis prevalence.Molecular techniques based on the amplification of parasite DNA have been shown to be a highly sensitive and specific method that allows the detection of different Entamoeba species. This study aimed to assess the frequency of the species from E. histolytica/dispar/moshkovskii complex by molecular and immunological techniques in individuals attended at a public health system in Salvador-Bahia, Brazil. A cross-sectional study involving 55,218 individuals was carried out. The diagnosis was based on microscopy revealing E. histolytica/dispar/moshkovskii complex. The species differentiation was performed by E. histolyticaspecific antigen, serological evaluation and by molecular technique. The overall prevalence of E. histolytica/dispar/moshkovskii complex determined by microscopy was approximately 0.49% (273/55,218). E. histolytica-specific antigen detection and molecular characterization returned 100% negativity for E. histolytica. However, serological evaluation returned an 8.9% positivity (8/90). In the stool samples analysed by PCR, it was not possible to identify E. histolytica and E. moshkovskii, although circulating IgG anti-E. histolytica has been detected

Alterations in the lipid profiles and circulating liver enzymes in individuals infected by Schistosoma mansoni

Abstract INTRODUCTION Portal hypertension and periportal fibrosis commonly occur in severe Schistosoma mansoni infection. Changes in lipid profile and elevated levels of circulating liver enzymes have also been described in infected individuals. The present study sought to assess the alterations in laboratory parameters associated with liver disorder in individuals infected by S. mansoni who visited a private routine laboratory service. Levels of circulating liver enzymes (gamma-glutamyl transferase [γ-GT], aspartate transaminase [AST], alanine transaminase [ALT], and alkaline phosphatase [ALP]) and a lipid panel (total cholesterol [COL], high-density lipoprotein [HDL], low-density lipoprotein [LDL], very low-density lipoprotein [VLDL], and triglycerides [TRI]) were evaluated in both infected and non-infected individuals and relative risk was used to measure associations. METHODS Data were collected for analysis from a total of 1,078 cases identified in 379,600 individuals who submitted samples to the Datalab Laboratory (Salvador, Bahia) between 2004 and 2008. RESULTS S. mansoni infection led to increased circulating levels of γ-GT in both women and men, AST (women), and ALP (men). S. mansoni infection was a protective factor against increased levels of TRI, CHO, and VLDL for individuals aged 19 years or older. The results of our analysis indicate that alterations in lipid metabolism and circulating liver enzymes in asymptomatic S. mansoni-infected individuals might be attributed to eggs lodged in the hepatic sinusoids. CONCLUSIONS Parasitological testing for S. mansoni should be indicated in endemic areas when this pattern of alterations is detected

Detection of anti-Trypanosoma cruzi antibodies by chimeric antigens in chronic Chagas disease-individuals from endemic South American countries

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2019-05-07T14:26:01Z No. of bitstreams: 1 Del-Rei et al., Detection ...2019.pdf: 2364416 bytes, checksum: 1fb04e34df00f90597065a5a189a69b6 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-05-07T16:39:03Z (GMT) No. of bitstreams: 1 Del-Rei et al., Detection ...2019.pdf: 2364416 bytes, checksum: 1fb04e34df00f90597065a5a189a69b6 (MD5)Made available in DSpace on 2019-05-07T16:39:03Z (GMT). No. of bitstreams: 1 Del-Rei et al., Detection ...2019.pdf: 2364416 bytes, checksum: 1fb04e34df00f90597065a5a189a69b6 (MD5) Previous issue date: 2019Fundación Bunge y Born 2012 Dr. Silvia Andrea Longhi; Consejo Nacional de Investigaciones Científicas y Tecnológicas PIP/0974-2011 Dr. Alejandro Gabriel Schijman; Gonçalo Moniz Institute PROEP/IGM 400904/2013-6 Dr. Mitermayer Galvão dos Reis;Coordination of Superior Level Staff Improvement CAPES - PROEX 0720/2018 Dr. Fred Luciano Neves Santos; National Council for Scientific and Technological Development CNPq Proc. No. 312195/2015-0 Dr. Nilson Ivo Tonin Zanchin; and National Council for Scientific and Technological Development CNPq Proc. No. 307319/2016-4 Dr. Mitermayer Galvão dos Reis. The funders were not involved in the design of the study, in the collection, analysis and interpretation of the data, or in writing the manuscript.Faculty of Technology and Sciences of Bahia. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Molecular Biology Institute of Paraná. Curitiba, PR, Brazil.Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Federal University of Bahia. Department of Pathology and Legal Medicine. Salvador, BA, Brazil / Yale University. School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven, Connecticut, United States of America.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.Institute for Research on Genetic Engineering and Molecular Biology “Dr Héctor Torres”. Laboratory of Molecular Biology of Chagas Disease. Buenos Aires, Argentina.Institute for Research on Genetic Engineering and Molecular Biology “Dr Héctor Torres”. Laboratory of Molecular Biology of Chagas Disease. Buenos Aires, Argentina.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Laboratory diagnosis of chronic Chagas disease is a troubling factor due to lack of reference tests. The WHO suggests the use of two distinct commercial serological tests in parallel. The performance of commercial immunoassays might fluctuate depending on the antigenic matrices and the local strains of T. cruzi in different geographical settings. The use of antigenic matrices based on chimeric proteins can solve these limitations. Here, we evaluated the diagnostic performance of two chimeric T. cruzi antigens (IBMP-8.1 and -8.4) to diagnose chronic Chagas disease in individuals from endemic South American countries

Highly Accurate Chimeric Proteins for the Serological Diagnosis of Chronic Chagas Disease: A Latent Class Analysis

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2018-10-23T12:17:11Z No. of bitstreams: 1 Santos FL Highly Accurate Chimeric...2018.pdf: 553405 bytes, checksum: a45acff4b655375c0b330fd036a1f045 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2018-10-23T12:34:46Z (GMT) No. of bitstreams: 1 Santos FL Highly Accurate Chimeric...2018.pdf: 553405 bytes, checksum: a45acff4b655375c0b330fd036a1f045 (MD5)Made available in DSpace on 2018-10-23T12:34:46Z (GMT). No. of bitstreams: 1 Santos FL Highly Accurate Chimeric...2018.pdf: 553405 bytes, checksum: a45acff4b655375c0b330fd036a1f045 (MD5) Previous issue date: 2018Gonçalo Moniz Institute, Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq (Proc. 404242/2012-0) and Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco-FACEPE (Proc. APQ-1257-2.11/12). W. V. Sousa and M. A. Krieger are research fellows of CNPq Proc. No. 306222/2013-2 and 590032/2011-9, respectively.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Fundação Oswaldo Cruz. Fio-Chagas. Rio de Janeiro, RJ, Brasil.Universidade Federal da Bahia. Instituto de Matemática. Departamento de Estatística. Salvador, BA, Brasil.Universidade Federal da Bahia. Instituto de Matemática. Departamento de Estatística. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Bio-Manguinhos. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Molecular Biology Institute of Paraná. Curitiba, PR, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Fio-Chagas. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil / Molecular Biology Institute of Paraná. Curitiba, PR, Brazil.Fundação Oswaldo Cruz. Fio-Chagas. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.The existence of an imperfect reference standard presents complications when evaluating the unbiased performance of novel diagnostic techniques. This is especially true in the absence of a gold standard, as is the case in chronic Chagas disease (CD) diagnosis. To circumvent this constraint, we elected to use latent class analysis (LCA). Previously, our group demonstrated the high performance of four Trypanosoma cruzi–chimeric proteins (Molecular Biology Institute of Parana´ [IBMP]-8.1, -8.2, -8.3, and -8.4) for CD diagnosis using several distinct immunoassays. Although commercial tests had previously been established as a reference standard, the diagnostic performance of these chimeric antigens could present bias because these tests fail to produce 100% accurate results. Thus, we used LCA to assess the performance of these IBMP chimeric antigens in chronic CD diagnosis. Using the LCA model as a gold standard, sensitivity and specificity values ranged from 93.5% to 99.4% and 99.6% to 100%, respectively. The accuracy values were 96.2% for IBMP-8.2, approximately 98% for IBMP-8.1 and IBMP-8.3, and nearly 100% for IBMP-8.4. For IBMP-8.1 and IBMP-8.2, higher positive predictive values were associated with increases in hypothetical prevalence. Similarly, higher hypothetical prevalence resulted in lower negative predictive values for IBMP-8.1, IBMP-8.2, and IBMP- 8.3. In addition, samples with serodiscordant results from commercial serological tests were analyzed using LCA. Molecular Biology Institute of Parana´ -8.1 demonstrated potential for use in confirmatory testing with regard to samples with inconsistent results. Moreover, our findings further confirmed the remarkable performance of the IBMP-8.4 antigen to diagnose chronic CD in both endemic and non-endemic areas

Immune reactivity to Trypanosoma cruzi chimeric proteins for Chagas disease diagnosis in immigrants living in a non-endemic setting

Abstract Background Chronic Chagas Disease (CD) diagnosis is based on serological methods employing crude, semipurified or recombinant antigens, which may result in low sensitivity or cross-reactivity. To reduce these restrictions, we developed a strategy involving use of molecules containing repetitive fragments of Trypanosoma cruzi conserved proteins. Diagnostic performance of IBMP-8.1 and IBMP-8.4 chimeric antigens (Molecular Biology Institute of Paraná - IBMP in Portuguese acronym) was assessed to diagnose T. cruzi-infected and non-infected immigrants living in Barcelona (Spain), a non-endemic setting for Chagas disease. Methods Reactivity of IBMP-8.1 and IBMP-8.4 was assessed using an in-house automated ELISA with 347 positive and 331 negative individuals to Chagas disease. Antigenic cross-reactivity was measured with sera samples from pregnant women with Toxoplasma gondii (n = 98) and Zika virus (n = 75) antibodies. Results The area under the curve values was 1 and 0.99 for the IBMP-8.1 and IBMP-8.4 proteins, respectively, demonstrating excellent diagnostic accuracy. The reactivity index was higher for IBMP-8.1 than IBMP-8.4 in positive samples and no significant difference in reactivity index was observed in negative samples. Sensitivity ranged from 99.4% for IBMP-8.1 to 99.1% for IBMP-8.4 and was not statistically different. Specificity for IBMP-8.1 reached 100 and 99.7% for IBMP-8.4, both nearly 100% accurate. No antigenic cross-reactivity was observed and reactivity index was similar to that for negative Chagas disease individuals. Conclusions Our results showed an outstanding performance of IBMP-8.1 and IBMP-8.4 chimeric antigens by ELISA and suggest both chimeric antigens could also be used for Chagas disease diagnosis in immigrants living in non-endemic settings

Cross-Reactivity Using Chimeric Trypanosoma cruzi Antigens: Diagnostic Performance in Settings Where Chagas Disease and American Cutaneous or Visceral Leishmaniasis Are Coendemic

O artigo encontra-se disponível em acesso aberto no site do Editor.Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2019-08-01T13:46:22Z No. of bitstreams: 1 Daltro RT Cross-1 reactivity...2019.pdf: 2605150 bytes, checksum: 7f3f42559f997cff016ee789573b69a7 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2019-08-01T14:02:44Z (GMT) No. of bitstreams: 1 Daltro RT Cross-1 reactivity...2019.pdf: 2605150 bytes, checksum: 7f3f42559f997cff016ee789573b69a7 (MD5)Made available in DSpace on 2019-08-01T14:02:44Z (GMT). No. of bitstreams: 1 Daltro RT Cross-1 reactivity...2019.pdf: 2605150 bytes, checksum: 7f3f42559f997cff016ee789573b69a7 (MD5) Previous issue date: 2019FIOCRUZ Technical Platform program for providing antigen purification infrastructure. Internal Research Support Program–PIAP Jovem (grant PIAP-001/2017); the Coordination of Superior Level Staff Improvement–CAPES (grant PROEX 0720/2018), the National Council for Scientific and Technological Development– CNPq (grants 479046/2011-5 and 400331/2012-8), Araucária Foundation (grant 05/2016), and Research Support Foundation of the State of Bahia (FAPESB).Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Faculty of Technology and Sciences of Bahia. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.Federal University of Rio Grande do Norte. Natal, RN, Brazil / Institute of Hygiene and Tropical Medicine. Lisbon, Portugal.Federal University of Rio Grande do Norte. Natal, RN, Brazil.Federal University of Rio Grande do Norte. Natal, RN, Brazil.Federal University of Rio Grande do Norte. Natal, RN, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil / Federal University of Bahia. Salvador, BA, Brazil.Federal University of Bahia. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Molecular Biology Institute of Paraná. Curitiba, PR, Brasil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brasil.Chimeric T. cruzi antigens have been proposed as a diagnostic tool for chronic Chagas disease (CD) in both settings where Chagas disease is endemic and those where it is not endemic. Antibody response varies in accordance to each T. cruzi strain, presenting challenges to the use of antigens lacking demonstrated cross-reactivity with Leishmania spp. Our group expressed four chimeric proteins (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) and previously assessed their diagnostic performance to determine cross-reactivity with Leishmania spp. Here, we validated our findings using serum samples from different Brazilian geographic areas reporting endemic Chagas disease, endemic visceral or American cutaneous leishmaniasis (ACL), or both. Overall, 829 serum samples were evaluated using commercial and IBMP enzyme-linked immunosorbent assays. Due to the absence of a reference assay to diagnosis CD, latent class analysis (LCA) was performed through the use of a statistical model. The incidence of cross-reactivity for ACL-positive samples varied from 0.35% (IBMP-8.3) to 0.70% (IBMP-8.1 and IBMP-8.2). Regarding visceral leishmaniasis (VL)-positive samples, the IBMP-8.2 and IBMP-8.3 antigens cross-reacted with six (3.49%) and with only one sample (0.58%), respectively. No cross-reactivity with either ACL or VL was observed for the IBMP-8.4 antigen. Similarly, no cross-reactions were found when VL-positive samples were assayed with IBMP-8.1. The agreement among the results obtained using IBMP antigens ranged from 97.3% for IBMP-8.2 and 99% for IBMP-8.1 and IBMP-8.3 to 100% for IBMP-8.4, demonstrating almost perfect agreement with LCA. Accordingly, in light of the negligible cross-reactivity with both ACL and VL, we suggest the use of IBMP antigens in regions where T. cruzi and Leishmania spp. are coendemic

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved