Brazil has more than one million Indigenous people, with the highest populations concentrated in the North and Center-West regions. These regions have significant Indigenous populations, so this provides essential insights into their genetic heritage. This study aimed to investigate the genomic ancestry of Indigenous groups in these areas by ten Ancestry Informative Markers (AIMs) described with frequency differential > 30% between parental populations. By analyzing these markers, we determined the ancestral genetic profile for European (EUR), African (AFR), and Amerindian (AME) ancestry within indigenous (IND) from the North (Tiriyó and Waiampi) and Center-West (Jaguapiru and Bororó) of Brazil. Peripheral blood samples were collected from three hundred and two indigenous people, and genomic DNA was extracted to identify AIMs through PCR. The genomic ancestry results showed that Tiriyó was AME: 74.1, EUR: 14.7, AFR: 11.2; Waiampi, AME: 49.3, EUR: 35.7, AFR: 15.0; Jaguapiru and Bororó AME: 47.1, EUR: 42.8, AFR: 10.2. These findings indicate that indigenous populations have preserved mainly their Amerindian ancestral contributions, despite varying levels of European and African admixture. While the AIMs effectively distinguished between AFR and IND ancestries, they were less precise in differentiating between EUR and IND. Understanding the genetic profile of indigenous Brazilians is essential to identifying genetic predispositions and specific health risks, allowing for personalized interventions and more inclusive public health policies.

Brucella suis is a zoonotic intracellular pathogen responsible for brucellosis, mainly in swine and humans. Although numerous genome sequences are publicly available, an integrative genomic analysis combining pan-genome architecture, structural organization, evolutionary relationships, and vaccine-associated targets remains limited. In this study, we analyzed 91 publicly available B.suis genomes to characterize their pan-genome composition and genomic structure. The pan-genome exhibited an open configuration, indicating continued genomic diversification. A total of 2,146 core genes were identified, representing conserved functions essential for species maintenance, while the accessory genome reflected strain-level variability. Phylogenetic reconstruction based on single-copy orthologs revealed distinct evolutionary clades among the strains. A complementary phylogenetic analysis of pan-genome gene presence–absence patterns further supported clade differentiation and highlighted variation in accessory gene repertoires. Comparative synteny and genome structural analyses demonstrated largely conserved chromosomal organization with localized rearrangements across strains. Screening of the core proteome identified 64 putative antigenic proteins with predicted surface localization and immunogenic properties. Additionally, resistance-associated determinants related to tetracycline and doxycycline were detected in one genome within the dataset. This comprehensive genomic analysis defines the pan-genome structure, evolutionary relationships, and genome organization of B.suis. The integration of core and pan-genome-based phylogenies provides complementary insights into strain diversification, while the identified conserved antigenic candidates offer a foundation for future experimental validation and rational vaccine development strategies.

Dendritic cells (DCs) are essential immune system sentinels, playing a key role in activating naïve T cells against leukemic cells. They have an immunomodulatory function, promoting an immune response and, at the same time, regulating immune tolerance to avoid excessive reactions. Plasmacytoid dendritic cell (pDC) neoplasms are a complex group of disorders, and among the subtypes, acute myeloid leukemia (AML) with pDC dermatosis (AML-pDC) stands out. In this context, pDCs can play an immunomodulatory role by inhibiting or promoting immune responses and acting as tumor progenitors since, in some cases, they can collaborate with the tumor microenvironment, favoring immune evasion and proliferation. However, the clinical significance of pDC in AML is not fully understood. Studies suggest that the interaction of pDCs with the leukemic microenvironment may contribute to disease progression by impairing the immune system’s ability to control tumor cells. Understanding the role of DCs in neoplasia is crucial, as it provides important insights for new studies seeking advances in innovative therapeutic strategies, such as dendritic cell vaccines. These vaccines are promising, with low toxicity and the potential to improve the prognosis of individuals affected by AML, stimulating an effective immune response.

Background COVID-19 vaccination of minors is crucial for global pandemic control, especially among indigenous populations, who are often more vulnerable due to limited healthcare resources and communal living settings. Objectives To assess the immunogenicity responses of the BNT162b2 vaccine in immunized Brazilian indigenous adolescents. Methods A cohort study was conducted with indigenous adolescents aged 12 to 18 years residing in the largest peri-urban indigenous region in Brazil. SARS-CoV-2-specific immune responses were analyzed before (D1) and after (D2) completion of the vaccination schedule. Demographic data were collected using a questionnaire. Results Of the 129 adolescents invited, 98 (75.96 %) participated in the study. Most were of Guarani ethnicity, single, had lower incomes, and were educated only to the elementary level. Post-vaccination, a statistically significant increase was noted in IgG concentration (24.03 % to 37.02 %). Increases were observed in B lymphocytes (11.88 to 13.92 cells/mm3), memory B cells (13.58 to 15.96 cells/mm3), NK cells (20.23 to 24.08 cells/mm3), and non-classical monocytes (9.23 to 11.34 cells/mm3), while CD8+ T cells decreased (24.41 to 21.69 cells/mm3). Adolescents with prior exposure to the virus showed increased levels of B lymphocytes and CD8+ T cells. No significant changes were observed in other cell subpopulations from exposure to the virus. Conclusion Elevated levels of antibodies and certain cell subpopulations were observed in vaccinated adolescents, confirming the effectiveness of the BNT162b2 vaccine in maintaining humoral and cellular responses. This study is the first to describe data from indigenous minors vaccinated against COVID-19 with the BNT162b2 vaccine, highlighting the importance of vaccination efforts and the potential need for booster doses.

Objective: To evaluate the hematological and lymphocyte profiles of individuals with COVID-19, as well as to identify the ancestral profile through Ancestry Informative Markers from two cities in the Northeast region of Brazil. Methods: Data from 58 individuals with COVID-19 who presented mild (39) and severe (19) clinical conditions were analyzed. The lymphocyte profile was identified by immunophenotyping and genotyping via PCR and qPCR analysis. Data were analyzed by descriptive statistics using IBM SPSS Statistics software. The study was approved by the Research Ethics Committee (ICS-UFBA). Results: Individuals in the severe group showed an increase in total leukocytes and neutrophils, and a decrease in erythrocytes, hemoglobin, hematocrit, and lymphocytes compared to individuals in the mild group. Likewise, the severe group showed a decrease in the cellular profiles of CD4+ T cells, CD8+ T cells, and B lymphocytes. Regarding the ancestral profile, both groups had a greater European ancestral genomic profile. However, the severe group had a higher percentage of African ancestry compared to the mild group. Conclusion: Ancestry was not associated with severity, but the results match findings that individuals' immune responses play a crucial role in COVID-19.

Considerando a importância da linfadenite caseosa, pela perda econômica gerada e potencial zoonótico, no maior estado produtor de ovinos do Brasil, aliado ao fato da necessidade de atualização de dados, o presente trabalho buscou apresentar o perfil soroepidemiológico em animais provenientes de mesorregiões da Bahia com grande produção de ovinos. Realizado um estudo transversal, com análise epidemiológica e apresentação espacial, utilizando soros ovinos, provenientes de parceria com a Agência de Defesa Agropecuária, testados por ELISA indireto para IgG anti-Corynebacteruim. Utilizando estatística descritiva e analítica, por análises univariada e multivariada dos dados, e elaboração de mapas temáticos. Identificou-se 327 positivos (31,9%). Maior positividade proporcional (75%), foram em Fátima, Jeremoabo e Paulo Afonso. Dos municípios testados, 18 (51,4%) apresentaram uma positividade maior que a média, e entre eles, destaca-se Pintadas (46% de positividade). Quanto as propriedades, apenas quatro (7,8%), não tiveram positividade. A prevalência identificada foi de 1/10.000 animais, destaque para Brumado (25,1/10.000), Pintadas (21,6/10.000) e Antas (15,5/10.000). Considerando o perfil epidemiológico verificamos a maior ocorrência de positivos entre machos (36,2%) (p-valor 0,104), de raça (38,5%), especialmente White Dorper (100%) e Santa Inês (53,5%) (p-valor<0,005), com idade acima de 36 meses (38,6%) (p-valor<0,001). A alta soropositividade da linfadenite caseosa sugere ampla disseminação da doença, destacando a urgente necessidade de implementar medidas eficazes de controle e aprimoramento do manejo sanitário dos rebanhos. O Estudo identifica áreas e perfis epidemiológico de maior risco para a doença, o que deve pautar estratégias preventivas a serem implementadas por instituições governamentais e da iniciativa privada.

Indigenous communities in Brazil have a complex epidemiological profile, which increases their chances of contracting sexually transmitted diseases. However, limited data is available on Treponema pallidum infections in this population. We investigated the seroprevalence and risk factors associated with T. pallidum infection in an indigenous population of Dourados, Mato Grosso do Sul. Blood samples were collected from September 2017 to March 2020, and the participants were interviewed to obtain comprehensive data on demography and sexual behavior. Serological tests were performed to detect T. pallidum infection. Besides conducting descriptive analysis, we performed Chi-squared tests and determined the bivariate odds ratio. The data were also analyzed using logistic regression. Among the 2190 invited individuals, 1927 (88%) were included in this study. The seroprevalence of T. pallidum infection was 2.91%. The results of a multivariate analysis showed that individuals who were 30–39 years old, with up to 4 years of school education, living in households without piped water, with a history of genital lesions, multiple sexual partners, and having a history of STIs had the highest seroprevalence of T. pallidum. This study showed that behavioral, social, and economic factors play an important role in the transmission of T. pallidum within the indigenous population. Thus, targeted intervention, including imparting education in the native language, mass testing initiatives, and implementing public policies to improve socioeconomic indicators, is needed to reduce the cases of syphilis in this community.

Introduction: Although the adaptive immune responses to the CoronaVac vaccine are known, their dynamics in indigenous communities remain unclear. In this study, we assessed the humoral and cellular immune responses to CoronaVac (Sinovac Biotech Life Sciences, 2021 NCT05225285, Beijing, China), in immunized Brazilian indigenous individuals. Methods: We conducted a prospective cohort study on indigenous Brazilian people between February 2021 and June 2021. Analyses of immune responses were carried out before (T1) and after a vaccination schedule was completed (T2). Demographic data were collected using a questionnaire. Results: We initially included 328 patients; among them, 120 (36.6%) had no SARS-CoV-2 antibodies. Peripheral blood mononuclear cells (PBMCs) were collected from 106 patients during follow-up visits, of which 91 samples were analyzed by immunophenotyping assay to detect SARS-CoV-2-specific memory T-cell response. Post-vaccination, the levels of memory B-cells and Natural Killer T-lymphocytes increased. Bororó village residents, females, and Terena ethnic group members had higher levels of anti-spike IgG antibodies post-vaccination, whereas alcohol and tobacco users had lower concentrations. Conclusions: To our best knowledge, this was the first comprehensive assessment of antibody and T-cell responses against CoronaVac vaccination in indigenous patients. Our findings showed that antibody response and T-cell immunity against SARS-CoV-2 were present in most patients following the vaccination schedule.

Objective: Estimate the seroprevalence of Zika virus in pregnant women in the macroregion of Dourados - MS. Methods: Pregnant women admitted to the Tertiary Hospital from January 2016 to December 2017 were selected, and a serological diagnosis was made using the antibody neutralization technique for the quantification of antibodies against ZIKV with Operetta high-performance image analysis system (PerkinElmer). The study was approved by the Research Ethics Committee. Results: 100 samples were analyzed, and the prevalence of identified ZIKV was 2%. Myalgia and ostealgia (90%) and high fever (75%) were the most common symptoms. Moreover, >50% of the cases reported a regular use of repellents. Maternal ZIKV infection was associated with premature childbirth and Inter-Atrial Communication but not with neurological alterations. Conclusion: These results demonstrated the importance and need for creating public policies to mitigate the possibility of damage caused by ZIKV, raising awareness among pregnant women regarding the use of repellents and other forms prevention, such as combating vectors, and investing the availability of new ZIKV vaccines.

Identifying individuals and factors associated with severe cases of COVID-19 is crucial as the pandemic continues to spread globally. Effective biomarkers for predicting severe cases are essential for optimizing clinical man-agement, therapy, and preventing unfavorable outcomes. This exploratory observational study aimed to inves-tigate the expression of dysregulated immune response genes (ARG1, NOS2, ITGA4, and SELPLG) in total leukocytes, plasmatic levels of P-selectin and PSGL-1, and their clinical associations in patients with mild and severe COVID-19. Data from 117 confirmed COVID-19 patients (severe = 58, mild = 59) were collected upon admission. Gene expression was measured using RT-qPCR, and plasma protein levels assessed with ELISA assay. The severe COVID-19 patient group had a higher median age of 62.0 (p = 0.0001), a higher proportion of black individuals (86.2%, p < 0.0001), and more males (65.5%, p = 0.007). The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were significantly higher in the severe COVID-19 patient group (p < 0.0001), indicating ongoing systemic inflammation. Severe COVID-19 patients also exhibited increased expression of ARG1 (p < 0.05) and SELPLG (p < 0.0001) genes, as well as higher concentrations of soluble P-selectin (p < 0.005) and PSGL-1 (p < 0.05) proteins. Multivariate analysis revealed that NLR, PLR, the expression of SELPLG and sPSGL-1 were independent predictors of COVID-19 severity. In conclusion, this study suggests that biomarkers of endothelial dysfunction and dysregulated leukocyte responses are associated with COVID-19 severity, serving as promising predictive tools for optimizing clinical management and patient monitoring.

BACKGROUND:The high structural similarity between the Zika virus (ZIKV) and other flaviviruses, such as Dengue Virus (DENV), complicates the identification of the infecting virus due to the occurrence of cross-reactions in serological assays. This phenomenon has increased the demand for more specific antigens for immunodiagnostic applications.METHODS:The present work aimed to identify specific regions of ZIKV and produce unique antigens through computational methods, molecular and microbiological techniques.RESULTS:Based on the computational analysis we successfully expressed two recombinant proteins derived from specific regions of the ZIKV. Through serological assays using characterized sera, we observed that the region 146-182 of ZIKV's E protein, expressed in tandem, was not reactive despite the predictive sensitivity and specificity observed by computer analyses. On the other hand, the non-denatured fraction 220-352 of ZIKV's NS1 showed greater specificity to IgG+ sera of ZIKV by dot blot and western blot, which highlights its properties as a possible tool in the diagnosis of ZIKV.CONCLUSION:These findings demonstrate that ZIKV NS1 fraction 220-352 is a potential tool that may be applied in the development of serological diagnosis. We also provided data that suggest the non-applicability of the region 146-182 of ZIKV's protein E in serological assays despite previous indications about its potential based on computational analysis.

Objective: The establishment of reference values for a subset of leukocytes is common in clinical practice, and ethnic variations are strongly associated with disease development. In Brazil, indigenous people are vulnerable to infections, and few studies have described the health and disease conditions of this population. This study aimed to provide reference values for immunological cell subsets in indigenous Brazilians living in the state of Mato Grosso do Sul. Methods: Flow cytometry and 4-color combinations of monoclonal antibodies were used to characterize cells. A total of 115 healthy adults, mostly females (72%), were included in the study. The results are presented as mean and median (2.5%-97.5% percentiles) for T and B lymphocytes, CD4+ T cells, CD8+ T cells, Natural Killer cells, monocytes, and dendritic cells, providing an average immunological profile for the population in question. Results: The relative medians of CD3+, CD4+, and CD8+ T cells were significantly higher in women than in men in a healthy indigenous population. Conclusion: To our knowledge, cell reference data from indigenous Brazilians are unknown in the literature. The immune cell results presented in this pioneering study will contribute to the clinical and laboratory evaluation of the Brazilian indigenous population, especially given the important differences when compared with other Brazilian ethnic groups.

Background:The COVID-19 pandemic had a major impact on indigenous populations. Understanding the viral dynamics within this population is essential to create targeted protection measures.Methods:A total of 204 SARS-CoV-2 positive samples collected between May 2020 and November 2021 from an indigenous area in Mato Grosso do Sul (MS), Midwestern Brazil, were screened. Samples were submitted to whole genome sequencing using the Nanopore sequencing platform. Clinical, demographic, and phylogenetic data were analyzed.Results:We found the co-circulation of six main SARS-CoV-2 lineages in the indigenous population, with the Zeta lineage being the most prevalent (27.66%), followed by B.1.1 (an ancestral strain) (20.21%), Gamma (14.36%) and Delta (13.83%). Other lineages represent 45.74% of the total. Our phylogenetic reconstruction indicates that multiple introduction events of different SARS-CoV-2 lineages occurred in the indigenous villages in MS. The estimated indigenous population mortality rate was 1.47%. Regarding the ethnicity of our cohort, 64.82% belong to the Guarani ethnicity, while 33.16% belong to the Terena ethnicity, with a slightly higher prevalence of males (53.43%) among females. Other ethnicities represent 2.01%. We also observed that almost all patients (89.55%) presented signs and symptoms related to COVID-19, being the most prevalent cough, fever, sore throat, and headache.Discussion:Our results revealed that multiple independent SARS-CoV-2 introduction events had occurred through time, probably due to indigenous mobility, since the villages studied here are close to urban areas in MS. The mortality rate was slightly below of the estimation for the state in the period studied, which we believe could be related to the small number of samples evaluated, the underreporting of cases and deaths among this population, and the inconsistency of secondary data available for this study.Conclusion:In this study, we showed the circulation of multiple SARS-CoV-2 variants in this population, which should be isolated and protected as they belong to the most fragile group due to their socioeconomic and cultural disparities. We reinforce the need for constant genomic surveillance to monitor and prevent the spread of new emerging viruses and to better understand the viral dynamics in these populations, making it possible to direct specific actions.

This study assessed the seroprevalence of SARS-CoV-2 in 496 asymptomatic individuals from Mato Grosso do Sul, located in Dourados, the largest periurban indigenous area in Brazil, from January 25 to February 4, 2021. The volunteers participated before receiving their first dose of the CoronaVac inactivated vaccine. For screening, blood samples were collected and analyzed using SARS-CoV-2 rapid tests and the enzyme-linked immunosorbent assay (ELISA). We observed varying trends in total anti-SARS-CoV-2 antibodies across different variables. Seropositivity among the participants tested was 63.70% (316/496) using the rapid test and 52.82% (262/496) were positive using the ELISA method. The majority of participants identified with the Guarani-Kaiowá ethnic group, with 66.15% (217/328), and other ethnic groups with 58.84% (193/328). The median age of the subjects was 30.5 years, with 79.57% (261/328) being femaleThis research showed the elevated seroprevalence of SARS-CoV-2 antibodies in asymptomatic Brazilians. The findings indicate a high seropositivity rate among the asymptomatic indigenous population of Midwest Brazil. This underscores the overlooked status of these communities and underscores the need for targeted national initiatives that emphasize the protection of vulnerable ethnic groups in the fight against COVID-19.

Syphilis is caused by the bacterium Treponema pallidum. The diagnosis is based on clinical data and serological analysis; however, the sensitivity and specificity of such tests may vary depending on the type of test and stage of the infection. In order to overcome this premise, this study utilized the polymerase chain reaction (PCR) for the detection of T. pallidum DNA in whole blood samples of patients with syphilis. The blood samples from patients with or without symptoms of syphilis, but with positive results in enzyme-linked immunosorbent assay (ELISA), were included in this study. A venereal disease research laboratory (VDRL) test was performed for all collected sera samples. For PCR, the T. pallidum DNA was extracted from the collected blood samples and a specific primer set was designed to amplify 131 nucleotides of polA (Tp0105). The specificity of the primers was evaluated with the DNA of 17 different pathogens. From a total of 314 blood samples reactive in ELISA, 58.2% (183/314) of the samples were reactive in the VDRL test. In the PCR, 54% (168/314) of the ELISA-reactive samples were positive. In both tests (VDRL and PCR) 104 samples were positive. Of 104 positive samples for both tests, 71 were at the latent stage. Based on these results, it can be concluded that PCR with the designed set of primers can be utilized as a diagnostic method for T. pallidum detection in blood samples of patients with syphilis, especially those with latent infection. In addition, it can be utilized as a supplement for serological methods to improve the diagnosis of syphilis.

The incidence of syphilis has increased alarmingly over the years. Its diagnosis continues to be a challenge, leading to the search for new alternative and effective methods. The objective of this study was to select and evaluate three Treponema pallidum recombinant proteins for potential use in syphilis serodiagnosis. Bioinformatics analysis was performed with three T. pallidum antigens (Tp0684, Tp0750, and Tp0792) to assess their physical, antigenic, and structural characteristics. The antigens were chemically synthesized, recombinant plasmids were expressed in Escherichia coli BL21 Star™ (DE3), and the recombinant proteins were purified by nickel affinity chromatography. The antigenicity of the recombinant proteins was evaluated by western blotting and enzyme-linked immunosorbent assay (ELISA), using the sera from patients with primary and latent syphilis. In silico analysis indicated the antigenic potential once the exposed B cell epitopes were detected in the evaluated proteins. Sera from patients with primary and latent syphilis specifically recognized rTp0684, rTp0750, and rTp0792 recombinant antigens. Moreover, the rTp0684-ELISA receiver operating characteristic (ROC) analysis showed an area under the ROC curve of 0.99, indicating high diagnostic efficacy with 97.62% specificity and 95% sensitivity. In conclusion, rTp0684 showed better potential as an antigen for the development of syphilis serodiagnosis. Thus, bioinformatic analysis can be an important tool to guide the selection of antigens for serological diagnosis.

Corynebacterium pseudotuberculosis is a bacillus that causes caseous lymphadenitis in small ruminants, leading to great losses to rural producers; thus, an efficient diagnosis is necessary for using disease control measures. This study aimed to evaluate the antigenic potential of four C. pseudotuberculosis recombinant proteins (rSodC, rPknG, rNanH, and rSpaC) against sera of goat and sheep experimentally infected with one of three different C. pseudotuberculosis strains. Goats were infected with CAP76 or CAP21 strain (n = 10), sheep with VD57 strain (n = 6), and a group of not-infected animals (goats and sheep) were kept as a healthy control (healthy n = 12). Sera were collected at 0, 14, 60, 90, 180, or 190 days after inoculation for antigenicity testing using Western blotting and enzyme-linked immunosorbent assay (ELISA) techniques. Cross-reactivity tests with recombinant proteins were performed in goat serum experimentally vaccinated with Nocardia sp. or Rhodococcus equi bacterin. The rSodC protein showed discriminatory antigenic reactivity with a statistically significant difference against three different C. pseudotuberculosis strains evaluated in goats and sheep samples, while rPknG showed statistical significance only against two C. pseudotuberculosis strains evaluated in goats. rSodC was proved to be a strong candidate as a tool for diagnosis of C. pseudotuberculosis infection, once it was able to recognize antibodies against all strains evaluated in goats and sheep.