- Departamento de Microbiologia, Imunologia e Parasitologia, Federal University of Santa Catarina, Florianópolis, SC, Brazil, 88040-970.
- +554837212955
- B.Sc. in Biological Sciences - UFSC, Brasil (1991) and Ph.D. in Parasitology - UFMG, Brasil (1999). Visiting Ph.D. st... moreB.Sc. in Biological Sciences - UFSC, Brasil (1991) and Ph.D. in Parasitology - UFMG, Brasil (1999). Visiting Ph.D. student at MIMG/UCLA, USA (1998). Post-Doctoral Fellow at BMRC/UEA, UK (2007-2008). Professor of Cellular and Molecular Parasitology at UFSC since 1994 and CNPq Research Fellow (2000-2020). Head of the UFSC Dept. of Microbiology, Immunology and Parasitology (2016-2018). Scientific interests are related to the cell and molecular biology of pathogenic trypanosomatids, especially on the genera Trypanosoma and Leishmania.edit
- Dr. Alvaro José Romanha - Fiocruz, Brazil (PhD Supervisor), Dr. David A. Campbell - UCLA, USA (Visiting Scholar), Dr. Kevin M. Tyler - UEA, UK (Post-doc)edit
Detection of major capsid protein of infectious myonecrosis virus in shrimps using monoclonal antibodies Article in Journal of virological methods · October 2010
To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling... more
To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling of equal volumes from individually collected samples. Paired analysis of pooled and individual samples from 613 patients revealed 94 positive individuals. Having individual testing as reference, no false-positives or false-negatives were observed for swab pooling. In additional 18,922 patients screened with swab pooling (1,344 pools), mean Cq differences between individual and pool samples ranged from 0.1 (Cr.I. -0.98 to 1.17) to 2.09 (Cr.I. 1.24 to 2.94). Overall, 19,535 asymptomatic patients were screened using 4,400 RT-qPCR assays. This corresponds to an increase of 4.4 times in laboratory capacity and a reduction of 77% in required tests. Therefore, swab pooling represents a major alternative for reliable and large-scale screening of SARS-CoV-2 ...
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To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling... more
To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling of equal volumes from individually collected samples. Paired analysis of pooled and individual samples from 613 patients revealed 94 positive individuals. Having individual testing as reference, no false-positives or false-negatives were observed for swab pooling. In additional 18,922 patients screened with swab pooling (1,344 pools), mean Cq differences between individual and pool samples ranged from 0.1 (Cr.I. -0.98 to 1.17) to 2.09 (Cr.I. 1.24 to 2.94). Overall, 19,535 asymptomatic patients were screened using 4,400 RT-qPCR assays. This corresponds to an increase of 4.4 times in laboratory capacity and a reduction of 77% in required tests. Therefore, swab pooling represents a major alternative for reliable and large-scale screening of SARS-CoV-2 ...
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Research Interests:
Research Interests: Geography, Comparative sequence analysis, Biology, Brazil, Comparative Study, and 15 moreMedicine, Biological Sciences, Mice, Animals, Polymerase Chain Reaction, Santa Catarina, Cattle, Amino Acid Sequence, Rabies Virus, DNA sequence, Molecular Sequence Data, Nucleoprotein, reverse transcriptase polymerase chain reaction, Direct sequence, and Medical and Health Sciences
Although known to be highly endemic in the Amazon regions of Brazil, the presence of cutaneous leishmaniasis (CL) in the subtropical southern part of the country has largely been ignored. This study was conducted to demonstrate CL is... more
Although known to be highly endemic in the Amazon regions of Brazil, the presence of cutaneous leishmaniasis (CL) in the subtropical southern part of the country has largely been ignored. This study was conducted to demonstrate CL is emerging in the Brazilian state of Santa Catarina, as well as to characterize the epidemiological profile and Leishmania species involved. For this cross-sectional study, data from all CL cases from Santa Catarina, Brazil, reported to the Brazilian National Notifiable Diseases Information System from 2001 to 2009 were investigated. Amplification of the kDNA minicircle conserved region followed by restriction fragment length polymorphism (PCR-RFLP) was conducted to screen for Leishmania species present in patient biopsy. Overall, 542 CL cases were reported, with majority resulting from autochthonous transmission (n = 401, 73.99%) and occurring in urban zones (n = 422, 77.86%). Age, gender, zone of residence, origin of case, clinical form and case outcome...
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The western mesoregion of the state of Santa Catarina (SC), Southern Brazil, was heavily affected as a whole by the COVID-19 pandemic in early 2021. This study aimed to evaluate the dynamics of the SARS-CoV-2 virus spreading patterns in... more
The western mesoregion of the state of Santa Catarina (SC), Southern Brazil, was heavily affected as a whole by the COVID-19 pandemic in early 2021. This study aimed to evaluate the dynamics of the SARS-CoV-2 virus spreading patterns in the SC state from March 2020 to April 2021 using genomic surveillance. During this period, there were 23 distinct variants, including Beta and Gamma, among which the Gamma and related lineages were predominant in the second pandemic wave within SC. A regionalization of P.1-like-II in the Western SC region was observed, concomitant to the increase in cases, mortality, and the case fatality rate (CFR) index. This is the first evidence of the regionalization of the SARS-CoV-2 transmission in SC and it highlights the importance of tracking the variants, dispersion, and impact of SARS-CoV-2 on the public health systems.
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Human trypanosomiases and animal trypanosomoses are caused by distinct protozoan parasites of the genus Trypanosoma. The etiological agents of bovine trypanosomosis (BT) are T. vivax, T. congolense, or T. brucei, whose acute infections... more
Human trypanosomiases and animal trypanosomoses are caused by distinct protozoan parasites of the genus Trypanosoma. The etiological agents of bovine trypanosomosis (BT) are T. vivax, T. congolense, or T. brucei, whose acute infections are initially characterized by hyperthermia, following moderate to severe anemia, subcutaneous edema, lethargy, reduced milk production, progressive weight loss, enlarged lymph nodes, reproductive disorders and death. Animals that survive the acute phase might recover and progress to the chronic, often asymptomatic, phase of infection. Despite their low sensitivity due to the characteristic low parasitemia, simple and costless direct parasitological examinations are the preferred diagnostic methods for animals. Thus, most of the epidemiological studies of BT are based on serological techniques using crude antigen. In this study, we describe the use of the MyxoTLm recombinant protein as an antigen on serological assays. Anti-T. vivax IgM and anti-T. vi...
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Research Interests:
BACKGROUND Trypanosoma rangeli is a protozoan parasite that is non-virulent to the mammalian host and is morphologically and genomically related to Trypanosoma cruzi, whose proliferation within the mammalian host is controversially... more
BACKGROUND Trypanosoma rangeli is a protozoan parasite that is non-virulent to the mammalian host and is morphologically and genomically related to Trypanosoma cruzi, whose proliferation within the mammalian host is controversially discussed. OBJECTIVES We aimed to investigate the T. rangeli cell cycle in vitro and in vivo by characterizing the timespan of the parasite life cycle and by proposing a molecular marker to assess cytokinesis. METHODOLOGY The morphological events and their timing during the cell cycle of T. rangeli epimastigotes were assessed using DNA staining, flagellum labelling and bromodeoxyuridine incorporation. Messenger RNA levels of four genes previously associated with the cell cycle of trypanosomatids (AUK1, PLK, MOB1 and TRACK) were evaluated in the different T. rangeli forms. FINDINGS T. rangeli epimastigotes completed the cell cycle in vitro in 20.8 h. PLK emerged as a potential molecular marker for cell division, as its mRNA levels were significantly increased in exponentially growing epimastigotes compared with growth-arrested parasites or in vitro-differentiated trypomastigotes. PLK expression in T. rangeli can be detected near the flagellum protrusion site, reinforcing its role in the cell cycle. Interestingly, T. rangeli bloodstream trypomastigotes exhibited very low mRNA levels of PLK and were almost entirely composed of parasites in G1 phase. MAIN CONCLUSIONS Our work is the first to describe the T. rangeli cell cycle in vitro and proposes that PLK mRNA levels could be a useful tool to investigate the T. rangeli ability to proliferate within the mammalian host bloodstream.
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ABSTRACTTrypanosoma cruzi, a zoonotic kinetoplastid protozoan with a complex genome, is the causative agent of American trypanosomiasis (Chagas disease). The parasite uses a highly diverse repertoire of surface molecules, with roles in... more
ABSTRACTTrypanosoma cruzi, a zoonotic kinetoplastid protozoan with a complex genome, is the causative agent of American trypanosomiasis (Chagas disease). The parasite uses a highly diverse repertoire of surface molecules, with roles in cell invasion, immune evasion and pathogenesis. Thus far, the genomic regions containing these genes have been impossible to resolve and it has been impossible to study the structure and function of the several thousand repetitive genes encoding the surface molecules of the parasite. We here present an improved genome assembly of a T. cruzi clade I (TcI) strain using high coverage PacBio single molecule sequencing, together with Illumina sequencing of 34 T. cruzi TcI isolates and clones from different geographic locations, sample sources and clinical outcomes. Resolution of the surface molecule gene structure reveals an unusual duality in the organisation of the parasite genome, a core genomic region syntenous with related protozoa flanked by unique a...
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Mixed infections with Trypanosoma cruzi and Trypanosoma rangeli and their different genetic groups occur frequently in vertebrate hosts and are difficult to detect by serology. In the present study, we evaluated the limit of detection of... more
Mixed infections with Trypanosoma cruzi and Trypanosoma rangeli and their different genetic groups occur frequently in vertebrate hosts and are difficult to detect by serology. In the present study, we evaluated the limit of detection of polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) analysis of cytochrome oxidase II (COII) for the identification of genetic groups of these two parasites in blood and tissue from vertebrate hosts. Reconstitution experiments were performed using human blood (TcI/TcII and KP1+/KP1-) and mouse tissue (TcI/TcII). We tested blood from patients who were in the chronic phase of Chagas disease and tissue from animals that were experimentally infected with all possible combinations of six discrete typing units. In blood samples, T. cruzi and T. rangeli were detected when 5 parasites (pa) were present in the sample, and genetic groups were identified when at least 50 pa were present in the sample. T. cruzi alone could be detected ...
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SUMMARYThe infectivity and virulence of pathogenic trypanosomatids are directly associated with the efficacy of their antioxidant system. Among the molecules involved in the trypanosomatid response to reactive oxygen or nitrogen species,... more
SUMMARYThe infectivity and virulence of pathogenic trypanosomatids are directly associated with the efficacy of their antioxidant system. Among the molecules involved in the trypanosomatid response to reactive oxygen or nitrogen species, trypanothione reductase (TRed) is a key enzyme. In this study, we performed a molecular and functional characterization of the TRed enzyme fromTrypanosoma rangeli(TrTRed), an avirulent trypanosome of mammals. TheTrTRed gene has an open reading frame (ORF) of 1473 bp (~490 aa, 53 kDa) and occurs as a single-copy gene in the haploid genome. The predicted protein contains two oxidoreductase domains, which are equally expressed in the cytosol of epimastigotes and trypomastigotes. Nicotinamide adenine dinucleotide phosphate (NADPH) generation is reduced and endogenous H2O2production is elevated inT. rangeliChoachí strain compared withT. cruziY strain epimastigotes. Oxidative stress induced by H2O2does not induce significant alterations inTrTRed expressio...
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The specific detection and genetic typing of trypanosomes that infect humans, mammalian reservoirs, and vectors is crucial for diagnosis and epidemiology. We utilized a PCR-RFLP assay that targeted subunit II of cytochrome oxidase and... more
The specific detection and genetic typing of trypanosomes that infect humans, mammalian reservoirs, and vectors is crucial for diagnosis and epidemiology. We utilized a PCR-RFLP assay that targeted subunit II of cytochrome oxidase and 24Sα-rDNA to simultaneously detect and discriminate six Trypanosoma cruzi discrete typing units (DTUs) and two genetic groups of Trypanosoma rangeli (KP1+/KP1-) in intestinal contents of experimentally infected Rhodnius prolixus. The PCR assays showed that in 23 of 29 (79.4%) mixed infections with the six T. cruzi DTUs and mixed infections with individual DTUs and/or groups KP1+ and KP1-, both parasites were successfully detected. In six mixed infections that involved TcIII, the TcI, TcII, TcV, and TcVI DTUs predominated to the detriment of TcIII, indicating the selection of genetic groups. Interactions between different genetic groups and vectors may lead to genetic selection over TcIII. The elimination of this DTU by the immune system of the vector appears unlikely because TcIII was present in other mixed infections (TcIII/TcIV and TcIII/KP1+). Both molecular markers used in this study were sensitive and specific, demonstrating their usefulness in a wide geographical area where distinct genotypes of these two species are sympatric. Although the cellular and molecular mechanisms that are involved in parasite-vector interactions are still poorly understood, our results indicate a dynamic selection toward specific T. cruzi DTUs in R. prolixus during mixed genotype infections.
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Research Interests: Medical Microbiology, Biology, Oxidative Stress, Leishmania, Medicine, and 12 moreAnimals, Antioxidant Activity, Molecular cloning, Trypanosoma Cruzi, Public health systems and services research, Cysteine, Species Specificity, Amino Acid Sequence, Cystathionine Beta-Synthase, Trypanosoma rangeli, Molecular Sequence Data, and CYSTEINE SYNTHASE
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Research Interests:
Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals ( i ) extensive... more
Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals ( i ) extensive alternative pathways for energy generation, ( ii ) ≈500 ORFs for transport-related proteins, ( iii ) complex and extensive systems for stress adaptation and motility, and ( iv ) widespread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for...
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Research Interests: Engineering, Physics, Chemistry, Biology, Cell Cycle, and 15 moreLeishmania, Medicine, Multidisciplinary, Cell Division, Phylogeny, Genome evolution, Bacteria, Biological evolution, PLoS one, Purine, Protozoan Proteins, Invertebrate Genomes, Base Sequence, Leishmania Major, and Molecular Sequence Data
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A survey of the Trypanosoma vivax genome was carried out by the genome sequence survey (GSS) approach resulting in 1,086 genomic sequences. A total of 455 high-quality GSS sequences were generated, consisting of 331 non-redundant... more
A survey of the Trypanosoma vivax genome was carried out by the genome sequence survey (GSS) approach resulting in 1,086 genomic sequences. A total of 455 high-quality GSS sequences were generated, consisting of 331 non-redundant sequences distributed in 264 singlets and 67 clusters in a total of 135.5 Kb of the T. vivax genome. The estimation of the overall G+C content, and the prediction of the presence of ORFs and putative genes were carried out using the Glimmer and Jemboss packages. Analysis of the obtained sequences was carried out by BLAST programs against 12 different databases and also using the Conserved Domain Database, InterProScan, and tRNAscan-SE. Along with the existing 23 T. vivax entries in the GenBank, the 32 putative genes predicted and the 331 non-redundant GSS sequences reported herein represent new potential markers for the development of PCRbased assays for specific diagnosis and typing of Trypanosoma vivax.
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Research Interests: Genomics, Molecular Evolution, Biology, Malaria, Brazil, and 15 moreMedicine, Biological Sciences, Insecticides, Insecticide Resistance, Environmental Sciences, Anopheles, Female, Animals, Male, Molecular Phylogenetics and Evolution, Nucleic Acids, Oxford university, Genetic variation, Mosquitoes Vectors, and Insect Vectors
Research Interests: Biology, Medicine, Gene expression, RNA Editing, Transcriptome, and 14 moreBiological Sciences, Molecular, Mitochondrial DNA, Expressed Sequence Tags, Chagas disease, EST, Trypanosoma, Trypanosoma Cruzi, Protozoan Proteins, Open Reading Frame, Virulence Factors, UTR, Gene expression profiling, and Medical and Health Sciences
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Research Interests: Microbiology, Medical Microbiology, Biology, Indonesia, Brazil, and 15 moreImmunohistochemistry, Medicine, Gene expression, Escherichia coli, Animals, Method, Monoclonal Antibodies, Capsid, Journal of Virological Methods, Molecular cloning, Amino Acid Profile, Molecular weight, Elsevier, immunoglobulin G, and Molecular Sequence Data
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The needs for development and/or improvement of molecular approaches for microorganism detection and characterization such as polymerase chain reaction (PCR) are of high interest due their sensitivity and specificity when compared to... more
The needs for development and/or improvement of molecular approaches for microorganism detection and characterization such as polymerase chain reaction (PCR) are of high interest due their sensitivity and specificity when compared to traditional microbiological techniques. Considering the worldwide importance of human immunodeficiency virus type 1 (HIV-1) infection, it is essential that such approaches consider the genetic variability of the virus, the heterogeneous nature of the clinical samples, the existence of contaminants and inhibitors, and the consequent needs for standardization in order to guarantee the reproducibility of the methods. In this work we describe a nested PCR assay targeting HIV-1 virus gag and env genes, allowing specific and sensitive diagnosis and further direct characterization of clinical samples. The method described herein was tested on clinical samples and allowed the detection of HIV-1 presence in all samples tested for the gag gene and 90.9% for the env gene, revealing sensitivities of 1 fg and 100 fg, respectively. Also, no cross-reactions were observed with DNA from infected and noninfected patients and the method allowed detection of the env and gag genes on an excess of 10(8) and 10(4) of human deoxyribonucleic acid (DNA), respectively. Furthermore, it was possible to direct sequence all amplified products, which allowed the sub typing of the virus in clinical samples.
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Research Interests: Bioinformatics, Immunology, Molecular Biology, Biotechnology, Crustacea, and 15 moreBiology, Immunohistochemistry, Medicine, Biological Sciences, Escherichia coli, Mice, Animals, Economic Impact, Capsid, Inclusion Bodies, Immunoassay, Monoclonal Antibody, Heterologous Expression, Integumentary System, and Medical and Health Sciences
Research Interests: Molecular Biology, Biology, Brazil, Leishmania, Adolescent, and 15 moreMedicine, Biological Sciences, Leishmaniasis, Humans, Animals, Polymerase Chain Reaction, Monoclonal Antibodies, Middle Aged, Adult, Cutaneous Leishmaniasis, Monoclonal Antibody, Elsevier, Genetic Markers, Medical and Health Sciences, and Leishmania braziliensis
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Research Interests: Computer Graphics, Genomics, Biology, Biological Sciences, Data Visualization, and 15 moreSoftware, Environmental Sciences, Developing Country, Animals, Genome, Nucleic Acids, Computer User Interface Design, Trypanosoma Cruzi, Trypanosoma brucei, Trypanosoma brucei brucei, Plasmodium falciparum, Entamoeba histolytica, Protozoan Proteins, Internet, and Leishmania Major
We describe 2 bat-transmitted outbreaks in remote, rural areas of Portel and Viseu Municipalities, Par State, northern Brazil. Central nervous system specimens were taken after patients’ deaths and underwent immunofluorescent assay... more
We describe 2 bat-transmitted outbreaks in remote,
rural areas of Portel and Viseu Municipalities, Par State,
northern Brazil. Central nervous system specimens were
taken after patients’ deaths and underwent immunofluorescent
assay and histopathologic examination for rabies antigens;
also, specimens were injected intracerebrally into
suckling mice in an attempt to isolate the virus. Strains
obtained were antigenically and genetically characterized.
Twenty-one persons died due to paralytic rabies in the 2
municipalities. Ten rabies virus strains were isolated from
human specimens; 2 other cases were diagnosed by
histopathologic examination. Isolates were antigenically
characterized as Desmodus rotundus variant 3 (AgV3).
DNA sequencing of 6 strains showed that they were genetically
close to D. rotundus–related strains isolated in Brazil.
The genetic results were similar to those obtained by using
monoclonal antibodies and support the conclusion that the
isolates studied belong to the same rabies cycle, the virus
variants found in the vampire bat D. rotundus.
rural areas of Portel and Viseu Municipalities, Par State,
northern Brazil. Central nervous system specimens were
taken after patients’ deaths and underwent immunofluorescent
assay and histopathologic examination for rabies antigens;
also, specimens were injected intracerebrally into
suckling mice in an attempt to isolate the virus. Strains
obtained were antigenically and genetically characterized.
Twenty-one persons died due to paralytic rabies in the 2
municipalities. Ten rabies virus strains were isolated from
human specimens; 2 other cases were diagnosed by
histopathologic examination. Isolates were antigenically
characterized as Desmodus rotundus variant 3 (AgV3).
DNA sequencing of 6 strains showed that they were genetically
close to D. rotundus–related strains isolated in Brazil.
The genetic results were similar to those obtained by using
monoclonal antibodies and support the conclusion that the
isolates studied belong to the same rabies cycle, the virus
variants found in the vampire bat D. rotundus.
Research Interests:
Edited by Robert Haselkorn, University of Chicago, Chicago, IL, and approved July 7, 2003 (received for review April 11, 2003) Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil... more
Edited by Robert Haselkorn, University of Chicago, Chicago, IL, and approved July 7, 2003 (received for review April 11, 2003) Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of ...
Research Interests:
Research Interests:
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Background Anopheles (Kerteszia) cruzii was the most important vector of human malaria in southern Brazil between 1930–1960. Nowadays it is still considered an important Plasmodium spp. vector in southern and south-eastern Brazil,... more
Background Anopheles (Kerteszia) cruzii was the most important vector of human malaria in southern Brazil between 1930–1960. Nowadays it is still considered an important Plasmodium spp. vector in southern and south-eastern Brazil, incriminated for oligosymptomatic malaria. Previous studies based on the analysis of X chromosome banding patterns and inversion frequencies in An. cruzii populations from these areas have suggested the occurrence of three sibling species. In contrast, two genetically distinct groups among An. cruzii populations from south/south-east and north-east Brazil have been revealed by isoenzyme analysis. Therefore, An. cruzii remains unclear. Methods In this study, a partial sequence of the timeless gene (~400 bp), a locus involved in the control of circadian rhythms, was used as a molecular marker to assess the genetic differentiation between An. cruzii populations from six geographically distinct areas of Brazil. Results The timeless gene revealed that An. cruzi...
Research Interests: Genetics, Medical Microbiology, Malaria, Brazil, Plasmodium, and 15 moreHumans, Circadian Rhythm, Anopheles, Female, Animals, Polymerase Chain Reaction, Cryptic Species, Genetic Differentiation, Molecular Marker, Sibling Species, North East, Genetic variation, Southern Brazil, Insect Vectors, and Molecular Sequence Data
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Human sewage from Florianopolis (Santa Catarina, Brazil) was analyzed for severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) from October 2019 until March 2020. Twenty five ml of sewage samples were clarified and viruses... more
Human sewage from Florianopolis (Santa Catarina, Brazil) was analyzed for severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) from October 2019 until March 2020. Twenty five ml of sewage samples were clarified and viruses concentrated using a glycine buffer method coupled with polyethylene glycol precipitation, and viral RNA extracted using a commercial kit. SARS-CoV-2 RNA was detected by RT-qPCR using oligonucleotides targeting N1, S and two RdRp regions. The results of all positive samples were further confirmed by a different RT-qPCR system in an independent laboratory. S and RdRp amplicons were sequenced to confirm identity with SARS-CoV-2. Genome sequencing was performed using two strategies; a sequence-independent single-primer amplification (SISPA) approach, and by direct metagenomics using Illumina's NGS. SARS-CoV-2 RNA was
To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling... more
To minimize sample dilution effect on SARS-CoV-2 pool testing, we assessed analytical and diagnostic performance of a new methodology, namely swab pooling. In this method, swabs are pooled at the time of collection, as opposed to pooling of equal volumes from individually collected samples. Paired analysis of pooled and individual samples from 613 patients revealed 94 positive individuals. Having individual testing as reference, no falsepositives or false-negatives were observed for swab pooling. In additional 18,922 patients screened with swab pooling (1,344 pools), mean Cq differences between individual and pool samples ranged from 0.1 (Cr.I.-0.98 to 1.17) to 2.09 (Cr.I. 1.24 to 2.94). Overall, 19,535 asymptomatic patients were screened using 4,400 RT-qPCR assays. This corresponds to an increase of 4.4 times in laboratory capacity and a reduction of 77% in required tests. Therefore, swab pooling represents a major alternative for reliable and large-scale screening of SARS-CoV-2 in low prevalence populations.
elements are involved in a recombination mechanism for the generation of antigenic variation and evasion of the host immune response on these TcI strains. The comparative genomic analysis of the cohort of TcI strains revealed multiple... more
elements are involved in a recombination mechanism for the generation of antigenic variation and evasion of the host immune response on these TcI strains. The comparative genomic analysis of the cohort of TcI strains revealed multiple cases of such recombination events involving surface molecule genes and has provided new insights into T. cruzi population structure.
Human trypanosomiases and animal trypanosomoses are caused by distinct protozoan parasites of the genus Trypanosoma. The etiological agents of bovine trypanosomosis (BT) are T. vivax, T. congolense, or T. brucei, whose acute infections... more
Human trypanosomiases and animal trypanosomoses are caused by distinct protozoan parasites of the genus Trypanosoma. The etiological agents of bovine trypanosomosis (BT) are T. vivax, T. congolense, or T. brucei, whose acute infections are initially characterized by hyperthermia, following moderate to severe anemia, subcutaneous edema, lethargy, reduced milk production, progressive weight loss, enlarged lymph nodes, reproductive disorders and death. Animals that survive the acute phase might recover and progress to the chronic, often asymptomatic, phase of infection. Despite their low sensitivity due to the characteristic low parasitemia, simple and costless direct parasitological examinations are the preferred diagnostic methods for animals. Thus, most of the epidemiological studies of BT are based on serological techniques using crude antigen. In this study, we describe the use of the MyxoTLm recombinant protein as an antigen on serological assays. Anti-T. vivax IgM and anti-T. vivax IgG ELISA assays using purified MyxoTLm revealed specificity rates of 91.30 % and 95.65 % and sensitivity rates of 82.35 % and 88.23 %, respectively, being higher than reported for crude antigens. Also, MyxoTLm demonstrated a good performance to detect IgM (ROC curve area = 0.8568) and excellent performance to detect IgG (ROC curve area = 0.9565) when compared to a crude antigen. T. evansi crude antigen used in the indirect anti-T. vivax IgM ELISA reached 70.58 % sensitivity and 78.26 % specificity, and had a lower test performance (ROC curve area = 0.7363). When applied to the anti-T. vivax IgG ELISA, the crude antigen reached 82.35 % sensitivity and 69.56 % specificity, also presenting a low performance with area under the ROC curve of 0.7570. Therefore, the use of MyxoTLm as an antigen on serological diagnosis of BT revealed to increase the sensitivity and the specificity if compared to crude antigens.
The taxonomic status of Trypanosoma rangeli as well as the tools for its molecular characterization is briefly commented.
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Objetivando verificar a colonização de Panstrongylus megistus em ecótopos artificiais em Florianópolis foram examinados, de 1985 a 1992, 779 anexos peridomiciliares (524 galinheiros, 46 currais e 209 ranchos) em 9 localidades e 443... more
Objetivando verificar a colonização de Panstrongylus megistus em ecótopos artificiais em Florianópolis foram examinados, de 1985 a 1992, 779 anexos peridomiciliares (524 galinheiros, 46 currais e 209 ranchos) em 9 localidades e 443 domicílios no distrito de Lagoa, todos na Ilha de Santa Catarina. Todo o ecótopo, incluindo forro e porão das casas, era examinado após aplicação de líquido insentífugo (Pirisa a 5%). A pesquisa nos anexos peri-domiciliares revelou 3 galinheiros e um rancho positivo no distrito de Lagoa, onde foram também encontrados 2 domicílios colonizados pelo P. megistus, com a captura de ovos, ninfas e adultos em todos os ecótopos. Pesquisas dirigidas foram realizadas em dois outros domicílios e em uma escola, nos quais os moradores haviam detectado anteriormente exemplares de P. megistus e, em todos os 3, foi confirmada a colonização pelo triatomíneo. Nos 9 ecótopos artificiais foram coletados 559 ovos, 305 ninfas e 24 adultos de P. megistus, com um índice de infecç...