Epidemiological profile of malaria in a rural community in the Amazon, Mato Grosso State, Brazil, 2011.

BACKGROUND: More than 95% of malaria transmission in Brazil occurs in the Legal Amazon Region, which in 2010 recorded around 333,429 cases reported in the Epidemiological Surveillance Information System-Malaria (Sivep_malaria), presenting an annual parasitic incidence (IPA) of 13.1 cases/1000 inhabitants. METHODS: This was a descriptive study that measured the community prevalence of Plasmodium infection and its relationship with land use in Três Fronteiras District, Colniza Municipality, Mato Grosso State. Data were collected during household visits in July 2011, with blood collection from finger pricks for the preparation of thick smear slides, and completion of a standardized case notification form. A georeferenced database was analysed, with land use evaluated as categorical variables. A kernel density map was built to show the density of cases and their location. RESULTS: Of the 621 respondents, 68(11%) had Plasmodium infection: 39 (57.4%) with Plasmodium vivax, 27(39.7%) with Plasmodium falciparum and two (2.9%) with mixed infections. Among infected individuals, 49 (72.1%) were men. Cases of malaria were distributed over the district, with greater occurrence of cases per household in open areas close to the mining company and artisanal mining sites. The was a greater density of cases located in the gold mining region. CONCLUSION: Transmission of malaria in Três Fronteiras District has a heterogeneous distribution. Individuals residing in mining and timber extraction sites have increased occurrence of Plasmodium infection.

Identification and serological responses to a novel Plasmodium vivax merozoite surface protein 1 (PvMSP-1) derived synthetic peptide: a putative biomarker for malaria exposure.

Background: The integration of diagnostic methods holds promise for advancing the surveillance of malaria transmission in both endemic and non-endemic regions. Serological assays emerge as valuable tools to identify and delimit malaria transmission, serving as a complementary method to rapid diagnostic tests (RDT) and thick smear microscopy. Here, we evaluate the potential of antibodies directed against peptides encompassing the entire amino acid sequence of the PvMSP-1 Sal-I strain as viable serological biomarkers for P. vivax exposure. Methods: We screened peptides encompassing the complete amino acid sequence of the Plasmodium vivax Merozoite Surface Protein 1 (PvMSP-1) Sal-I strain as potential biomarkers for P. vivax exposure. Here, immunodominant peptides specifically recognized by antibodies from individuals infected with P. vivax were identified using the SPOT-synthesis technique followed by immunoblotting. Two 15-mer peptides were selected based on their higher and specific reactivity in immunoblotting assays. Subsequently, peptides p70 and p314 were synthesized in soluble form using SPPS (Solid Phase Peptide Synthesis) and tested by ELISA (IgG, and subclasses). Results: This study unveils the presence of IgG antibodies against the peptide p314 in most P. vivax-infected individuals from the Brazilian Amazon region. In silico B-cell epitope prediction further supports the utilization of p314 as a potential biomarker for evaluating malaria transmission, strengthened by its amino acid sequence being part of a conserved block of PvMSP-1. Indeed, compared to patients infected with P. falciparum and uninfected individuals never exposed to malaria, P. vivax-infected patients have a notably higher recognition of p314 by IgG1 and IgG3.

Natural genetic diversity of the DBL domain of a novel member of the Plasmodium vivax erythrocyte binding-like proteins (EBP2) in the Amazon rainforest.

In malaria parasites, the erythrocyte binding-like proteins (EBL) are a family of invasion proteins that are attractive vaccine targets. In the case of Plasmodium vivax, the widespread malaria parasite, blood-stage vaccines have been largely focused on a single EBL candidate, the Duffy binding-like domain (DBL) of the Duffy binding protein (DBPII), due to its well-characterized role in the reticulocyte invasion. A novel P. vivax EBL family member, the Erythrocyte binding protein (EBP2, also named EBP or DBP2), binds preferentially to reticulocytes and may mediate an alternative P. vivax invasion pathway. To gain insight into the natural genetic diversity of the DBL domain of EBP2 (region II; EBP2-II), we analyzed ebp2-II gene sequences of 71 P. vivax isolates collected in different endemic settings of the Brazilian Amazon rainforest, where P. vivax is the predominant malaria-associated species. Although most of the substitutions in the ebp2-II gene were non-synonymous and suggested positive selection, the results showed that the DBL domain of the EBP2 was much less polymorphic than that of DBPII. The predominant EBP2 haplotype in the Amazon region corresponded to the C127 reference sequence first described in Cambodia (25% C127-like haplotype). An overview of ebp2-II gene sequences available at GenBank (n = 352) from seven countries (Cambodia, Madagascar, Myanmar, PNG, South Korea, Thailand, Vietnam) confirmed the C127-like haplotype as highly prevalent worldwide. Two out of 43 haplotypes (5 to 20 inferred per country) showed a global frequency of 60%. The results presented here open new avenues of research pursuit while suggesting that a vaccine based on the DBL domain of EBP2 should target a few haplotypes for broad coverage.

Monoamine oxidase-A (MAO-A) low-expression variants and increased risk of Plasmodium vivax malaria relapses.

OBJECTIVES: Primaquine is essential for the radical cure of Plasmodium vivax malaria and must be metabolized into its bioactive metabolites. Accordingly, polymorphisms in primaquine-metabolizing enzymes can impact the treatment efficacy. This pioneering study explores the influence of monoamine oxidase-A (MAO-A) on primaquine metabolism and its impact on malaria relapses. METHODS: Samples from 205 patients with P. vivax malaria were retrospectively analysed by genotyping polymorphisms in MAO-A and cytochrome P450 2D6 (CYP2D6) genes. We measured the primaquine and carboxyprimaquine blood levels in 100 subjects for whom blood samples were available on the third day of treatment. We also examined the relationship between the enzyme variants and P. vivax malaria relapses in a group of subjects with well-documented relapses. RESULTS: The median carboxyprimaquine level was significantly reduced in individuals carrying low-expression MAO-A alleles plus impaired CYP2D6. In addition, this group experienced significantly more P. vivax relapses. The low-expression MAO-A status was not associated with malaria relapses when CYP2D6 had normal activity. This suggests that the putative carboxyprimaquine contribution is irrelevant when the CYP2D6 pathway is fully active. CONCLUSIONS: We found evidence that the low-expression MAO-A variants can potentiate the negative impact of impaired CYP2D6 activity, resulting in lower levels of carboxyprimaquine metabolite and multiple relapses. The findings support the hypothesis that carboxyprimaquine may be further metabolized through CYP-mediated pathways generating bioactive metabolites that act against the parasite.

Reference intervals for serum immunoglobulins G, M and E levels in Brazilian children aged 1 to 10 years: a population-based study

Abstract Objective: To determine the reference intervals (RI) for serum levels of IgG, IgM, and IgE in healthy children aged 1-10 years living in central Brazil. Method: A sample of 1743 healthy children was randomly selected from kindergartens and public schools. Reference intervals were defined by non-parametric rank (Clinical Laboratory Standards Institute, USA), bootstrapping, and Horn's robust methods. Results: By the rank method, the IgG RI was 792-1771 mg/dL for children of both sexes aged 1-10 years. IgM RI were different for gender and age groups, being 45-196 mg/dL and 34-190 mg/dL for boys aged 1-2 years and 3-10 years, respectively. For girls, the IgM RI were 50-212 mg/dL and 39-212 mg/dL, for ages 1-4 and 5-10 years, respectively. The IgE RI for both sexes and ages 1-10 years was 6-1005 mg/dL. The bootstrap method showed RI similar to the rank method but with slightly different confidence intervals. Horn's robust method determined RI different from those obtained by previous methods. Conclusion: RI for serum concentrations of IgG, IgM, and IgE were established for Brazilian children aged 1-10 years. This definition will be useful for Brazilian physicians, who will have more adequate parameters for their clinical decision-making.

Investigating the Yanomami malaria outbreak puzzle: surge in mining during Bolsonaro's government triggered peak in malaria burden.

The Yanomami, an Indigenous people from the Amazon, confront multifaceted challenges endangering their health and cultural integrity. Of immediate concern is the surge in malaria cases in their territory during Bolsonaro's government. We investigated the impact of land use on malaria incidence among the Yanomami leveraging satellite imagery and ran difference-in-differences analyses to ask whether the Yanomami suffered disproportionately from malaria when illegal mining was rising in the region (2016-2022). We show a remarkable ~300% rise in malaria from 2016 to 2022 and point to mining as the primary driver of malaria among the Yanomami; when mining increases by 1%, malaria increases by 31%. After mining unfolded, the burden of malaria among the Yanomami was disproportionately higher, up to 15%, than in non-indigenous communities. Our findings underscore the impact of illegal mining on the high malaria burden suffered by the Yanomami and the importance of rainforest conservation and land sovereignty for Indigenous health.

Factors Associated with Overt Stroke in Children and Adolescents with Sickle Cell Disease: A Retrospective Cohort Study.

Sickle cell disease (SCD) is associated with a high occurrence of complications due to vaso-occlusive phenomenon such as stroke. This retrospective cohort study aimed to examine the clinical and laboratory characteristics of 120 children and adolescents with SCD and analyze the factors associated with overt stroke incidence. All relevant data were obtained from patient medical records. Survival analysis was used to compare the demographic, clinical, and laboratory characteristics between patients with and those without overt stroke. The patients were 52.5% female with a mean (SD) age of 11.2 (4.3) years. The incidence of overt stroke in this cohort was nine out of 956.7 patient-years, resulting in an incidence density of 0.94 cases/100 patient-years. Reports of greater than or equal to two previous attacks of dactylitis and greater than or equal to three episodes of acute chest syndrome (ACS)/pneumonia were associated with overt stroke and an increase in reticulocyte count and red blood cell distribution width (RDW). In conclusion, a history of a high number of dactylitis, ACS/pneumonia, increased RDW, and reticulocytosis was associated with overt stroke occurrence in children and adolescents with SCD. Future studies with a higher stroke incidence in the evaluated sample are necessary to confirm this hypothesis.

Live, Attenuated, Tetravalent Butantan-Dengue Vaccine in Children and Adults.

BACKGROUND: Butantan-Dengue Vaccine (Butantan-DV) is an investigational, single-dose, live, attenuated, tetravalent vaccine against dengue disease, but data on its overall efficacy are needed. METHODS: In an ongoing phase 3, double-blind trial in Brazil, we randomly assigned participants to receive Butantan-DV or placebo, with stratification according to age (2 to 6 years, 7 to 17 years, and 18 to 59 years); 5 years of follow-up is planned. The objectives of the trial were to evaluate overall vaccine efficacy against symptomatic, virologically confirmed dengue of any serotype occurring more than 28 days after vaccination (the primary efficacy end point), regardless of serostatus at baseline, and to describe safety up to day 21 (the primary safety end point). Here, vaccine efficacy was assessed on the basis of 2 years of follow-up for each participant, and safety as solicited vaccine-related adverse events reported up to day 21 after injection. Key secondary objectives were to assess vaccine efficacy among participants according to dengue serostatus at baseline and according to the dengue viral serotype; efficacy according to age was also assessed. RESULTS: Over a 3-year enrollment period, 16,235 participants received either Butantan-DV (10,259 participants) or placebo (5976 participants). The overall 2-year vaccine efficacy was 79.6% (95% confidence interval [CI], 70.0 to 86.3) - 73.6% (95% CI, 57.6 to 83.7) among participants with no evidence of previous dengue exposure and 89.2% (95% CI, 77.6 to 95.6) among those with a history of exposure. Vaccine efficacy was 80.1% (95% CI, 66.0 to 88.4) among participants 2 to 6 years of age, 77.8% (95% CI, 55.6 to 89.6) among those 7 to 17 years of age, and 90.0% (95% CI, 68.2 to 97.5) among those 18 to 59 years of age. Efficacy against DENV-1 was 89.5% (95% CI, 78.7 to 95.0) and against DENV-2 was 69.6% (95% CI, 50.8 to 81.5). DENV-3 and DENV-4 were not detected during the follow-up period. Solicited systemic vaccine- or placebo-related adverse events within 21 days after injection were more common with Butantan-DV than with placebo (58.3% of participants, vs. 45.6%). CONCLUSIONS: A single dose of Butantan-DV prevented symptomatic DENV-1 and DENV-2, regardless of dengue serostatus at baseline, through 2 years of follow-up. (Funded by Instituto Butantan and others; DEN-03-IB ClinicalTrials.gov number, NCT02406729, and WHO ICTRP number, U1111-1168-8679.).

Reference intervals for serum immunoglobulins G, M and E levels in Brazilian children aged 1 to 10 years: a population-based study.

OBJECTIVE: To determine the reference intervals (RI) for serum levels of IgG, IgM, and IgE in healthy children aged 1-10 years living in central Brazil. METHOD: A sample of 1743 healthy children was randomly selected from kindergartens and public schools. Reference intervals were defined by non-parametric rank (Clinical Laboratory Standards Institute, USA), bootstrapping, and Horn's robust methods. RESULTS: By the rank method, the IgG RI was 792-1771 mg/dL for children of both sexes aged 1-10 years. IgM RI were different for gender and age groups, being 45-196 mg/dL and 34-190 mg/dL for boys aged 1-2 years and 3-10 years, respectively. For girls, the IgM RI were 50-212 mg/dL and 39-212 mg/dL, for ages 1-4 and 5-10 years, respectively. The IgE RI for both sexes and ages 1-10 years was 6-1005 mg/dL. The bootstrap method showed RI similar to the rank method but with slightly different confidence intervals. Horn's robust method determined RI different from those obtained by previous methods. CONCLUSION: RI for serum concentrations of IgG, IgM, and IgE were established for Brazilian children aged 1-10 years. This definition will be useful for Brazilian physicians, who will have more adequate parameters for their clinical decision-making.

Application of a physiotherapeutic protocol associated with photobiomodulation for the treatment of leprosy patients.

Leprosy is a chronic infectious disease characterized by acute inflammatory episodes that affect the skin and peripheral nerves and can develop progressive and irreversible disabilities and deformities. In addition, drug therapy and physiotherapy offer resources and techniques capable of mitigating the consequences of neural lesions, but neural lesions can occur before, during, and even after drug treatment. Thus, new treatments are needed. Photobiomodulation (PBM) might be a promissor therapy since it aims to reduce the inflammatory process and restore motor and sensory functions in the affected area. This study aims to compare the evolution of neural status, pain, and functionality in patients with leprosy and neuritis after a physiotherapeutic protocol and PBM treatment. This was a randomized controlled clinical trial that analyzed a group of patients receiving a physiotherapeutic protocol (PPG) and another receiving physiotherapeutic protocol associated with PBM (PLG) (wavelength 904 nm, potency 70 mW, time per point 9 s). Our results showed when evaluating functional capacity limitations with the SALSA scale, the PLG patients improved from moderate to mild limitations. On the other hand, the PPG remained as moderate limitations. Also, the PLG showed a significant reduction in pain on the VAS scale. The neurological assessment showed that PLG improved palpation of the median, radial, and peroneal nerves. In the strength test, PLG patients improved in the 5th finger abduction and ankle dorsiflexion. Assessing sensitivity, it was identified an improvement in PLG for the ulnar nerve and tibial nerve. All those changes were statistically significant when compared to the PPG patients. Finally, the PLG patients improved disabilities, identified by the neurological assessment of the eyes, hands, and feet. In conclusion, this study demonstrated that combining a physiotherapeutic protocol with PBM treatment effectively improved functional status and reduced pain in leprosy patients.

Reference intervals for serum TSH concentrations of healthy children from the Central Region of Brazil.

Objective: The objective of this study was to determine the serum thyroid-stimulating hormone (TSH) concentration reference intervals (RIs) of healthy children aged 1 to 10 years of both sexes, living in the Central Region of Brazil. Subjects and methods: 1,735 children [869 (50.1%) female; 866 (49.9%) male] enrolled in the morning shift of 47 pre- and 83 public elementary schools in the municipality of Cuiabá, Mato Grosso, were studied by gathering anthropometric and social data and their medical history. A blood sample was collected from each child to determine the TSH concentration using the electrochemiluminescence method on a Cobas® 6000 modular analyzer (Analyzer series, Roche Diagnostics). Results: The RIs were determined using the 2.5 and 97.5 percentile and the mean ± 2 standard deviations methods. After identifying the homoscedastic groups by age and sex, outliers higher or lower than three standard deviations were excluded. The distribution of serum TSH concentrations showed no significant age or sex differences. Based on the percentile method, TSH RI ranged from 0.93 to 5.86 µIU/mL. Based on the mean ± 2 standard deviations, TSH RI ranged from 0.30 to 5.29 µIU/mL. Conclusion: The normal serum TSH concentration of the Brazilian children evaluated in this study differ from those of populations from other countries. Other regional population studies may validate the RIs found in this study and enable its safer use in pediatric clinical practice.

Prognostic value of neutrophil and lymphocyte counts and neutrophil/lymphocyte ratio for predicting death in patients hospitalized for COVID-19.

COVID-19 primarily affects the respiratory system and can cause changes in other systems. Early identification of patients with a higher potential for complications is critical to provide the best possible treatment to reduce the disease's lethality. This study aimed to analyze the behavior of hematologic biomarkers in predicting mortality in patients hospitalized with COVID-19. This retrospective cohort study used data from the medical records of patients hospitalized with COVID-19 between March and August 2020 in two referral hospitals for treatment of the disease in the city of Cuiabá (in the state of Mato Grosso, Brazil). Clinical and laboratory characteristics related to cardiovascular involvement and death during hospitalization were evaluated. Neutrophils, lymphocytes, and monocytes, as well as the neutrophil-to-lymphocyte ratio (NLR) and the monocyte-to-lymphocyte ratio (MRL), were used as potential biomarkers of death. A total of 199 patients were included (male: 113; mean age: 51.4 years). Leukocyte, neutrophil, and lymphocyte counts showed a statistically significant association with death, as did NLR and MRL. Satisfactory accuracy in predicting death was observed for leukocyte, neutrophil, lymphocyte, NLR, and MLR counts. The hematologic biomarkers studied may be useful for prognosticating hospitalized patients for the possibility of death from COVID-19.

Reference intervals for serum immunoglobulin A levels in Brazilian children aged 1 to 10 years: a population-based study.

OBJECTIVE: To determine reference intervals (RI) for serum immunoglobulin A (IgA) levels in healthy children aged 1 to 1 0 years residing in the central region of Brazil. METHODS: This cross-sectional study was conducted on 1,743 healthy children randomly selected from kindergartens and public schools in Cuiabá, MT, Brazil. The IgA RIs were defined using the statistical methods postulated by the guidelines of the United States Clinical and Laboratory Standards Institute, the nonparametric bootstrap method, and Horn's robust method after the correction of discrepancies by Tukey's, Dixon's, and Horn's methods, respectively. The results were defined based on the values contained between the 2.5th and 97.5th percentiles and their respective 95% confidence intervals. RESULTS: Partition by sex was not necessary to determine the IgA RI of the studied children. Homogeneous subgroups were identified among children aged 1-<2, 2-<5, and 5-<11 years, whose IgA-specific RIs were determined. CONCLUSION: The serum IgA RIs were established for three groups of Brazilian children aged 1-11 years, which differed from those currently applied in Brazilian pediatric practice and from those defined by international studies. This definition will help Brazilian pediatricians formulate an accurate diagnosis and facilitate decision-making.

Validation of a Simple Instrument of Fast Application to Track Disability in Leprosy Patients.

Objective To evaluate a simple and fast diagnostic instrument to be used by any health professional to track the disability presented by leprosy patients. Method Validation study of a diagnostic test performed in a sample of 156 leprosy patients to track functional disability through the shortened disabilities of arm, shoulder, and hand (QuickDASH) questionnaire . The simplified neurological assessment proposed by the World Health Organization was used as a reference. A receiver operating characteristic (ROC) curve was constructed to determine the cutoff point of QuickDASH that best discriminated patients with functional disability caused by leprosy. Results We identified 86 (55.5%) patients with functional disability by simplified neurological evaluation. The performance of the QuickDASH instrument showed that, at a cut-off point of 30 points, the sensitivity and specificity were 72.1% and 68.1% (accuracy of 70.3%), respectively, to identify functional disability, with a positive predictive value of 73.8%. Conclusion The QuickDASH instrument showed good accuracy to track functional disability in leprosy patients, and it may be useful in clinical practice of primary and general outpatient care, with the goal of identifying patients who need specialized reference for the prevention and treatment of this condition.

Validation of a Simple Instrument of Fast Application to Track Disability in Leprosy Patients / Validação de um instrumento simples e de aplicação rápida para rastrear incapacidade em pacientes com hanseníase

Abstract Objective To evaluate a simple and fast diagnostic instrument to be used by any health professional to track the disability presented by leprosy patients. Method Validation study of a diagnostic test performed in a sample of 156 leprosy patients to track functional disability through the shortened disabilities of arm, shoulder, and hand (QuickDASH) questionnaire. The simplified neurological assessment proposed by the World Health Organization was used as a reference. A receiver operating characteristic (ROC) curve was constructed to determine the cutoff point of QuickDASH that best discriminated patients with functional disability caused by leprosy. Results We identified 86 (55.5%) patients with functional disability by simplified neurological evaluation. The performance of the QuickDASH instrument showed that, at a cut-off point of 30 points, the sensitivity and specificity were 72.1% and 68.1% (accuracy of 70.3%), respectively, to identify functional disability, with a positive predictive value of 73.8%. Conclusion The QuickDASH instrument showed good accuracy to track functional disability in leprosy patients, and it may be useful in clinical practice of primary and general outpatient care, with the goal of identifying patients who need specialized reference for the prevention and treatment of this condition.

Resumo Objetivo Avaliar um instrumento diagnóstico simples e rápido a ser utilizado por qualquer profissional da saúde para rastrear a incapacidade apresentada por pacientes com hanseníase. Método Estudo de validação de teste de diagnóstico realizado em uma amostra de 156 pacientes com hanseníase para rastrear incapacidade funcional, por meio do questionário abreviado disabilities of arm, shoulder, and hand (QuickDASH). A avaliação neurológica simplificada proposta pela Organização Mundial da Saúde foi utilizada como referência. Construiu-se a curva de características operacionais do receptor (ROC) para determinação do ponto de corte do QuickDASH que melhor discriminou pacientes com incapacidade funcional provocada pela hanseníase. Resultados Foram identificados 86 (55,5%) pacientes com incapacidade funcional pela avaliação neurológica simplificada. O desempenho do QuickDASH mostrou que, em ponto de corte de 30 pontos, a sensibilidade e a especificidade foram de 72,1% e 68,1% (acurácia de 70,3%), respectivamente, para identificar incapacidade funcional, com um valor preditivo positivo de 73,8%. Conclusão O instrumento QuickDASH mostrou boa acurácia para rastrear incapacidade funcional no paciente com hanseníase, podendo ser útil na prática clínica da atenção básica e ambulatorial geral, com o objetivo de identificar pacientes que necessitam de referência especializada para sua prevenção e tratamento.

Reference intervals for serum TSH concentrations of healthy children from the Central Region of Brazil

ABSTRACT Objective: The objective of this study was to determine the serum thyroid-stimulating hormone (TSH) concentration reference intervals (RIs) of healthy children aged 1 to 10 years of both sexes, living in the Central Region of Brazil. Subjects and methods: 1,735 children [869 (50.1%) female; 866 (49.9%) male] enrolled in the morning shift of 47 pre- and 83 public elementary schools in the municipality of Cuiabá, Mato Grosso, were studied by gathering anthropometric and social data and their medical history. A blood sample was collected from each child to determine the TSH concentration using the electrochemiluminescence method on a Cobas® 6000 modular analyzer (Analyzer series, Roche Diagnostics). Results: The RIs were determined using the 2.5 and 97.5 percentile and the mean ± 2 standard deviations methods. After identifying the homoscedastic groups by age and sex, outliers higher or lower than three standard deviations were excluded. The distribution of serum TSH concentrations showed no significant age or sex differences. Based on the percentile method, TSH RI ranged from 0.93 to 5.86 μIU/mL. Based on the mean ± 2 standard deviations, TSH RI ranged from 0.30 to 5.29 μIU/mL. Conclusion: The normal serum TSH concentration of the Brazilian children evaluated in this study differ from those of populations from other countries. Other regional population studies may validate the RIs found in this study and enable its safer use in pediatric clinical practice.

Reference intervals for serum immunoglobulin A levels in Brazilian children aged 1 to 10 years: a population-based study

Abstract Objective: To determine reference intervals (Rl) for serum immunoglobulin A (IgA) levels in healthy children aged 1 to 1 0 years residing in the central region of Brazil. Methods: This cross-sectional study was conducted on 1,743 healthy children randomly selected from kindergartens and public schools in Cuiabá, MT, Brazil. The IgA RIs were defined using the statistical methods postulated by the guidelines of the United States Clinical and Laboratory Standards Institute, the nonparametric bootstrap method, and Horn's robust method after the correction of discrepancies by Tukey's, Dixon's, and Horn's methods, respectively. The results were defined based on the values contained between the 2.5th and 97.5th percentiles and their respective 95% confidence intervals. Results: Partition by sex was not necessary to determine the IgA Rl of the studied children. Homogeneous subgroups were identified among children aged 1-<2, 2-<5, and 5-<11 years, whose IgA-specific RIs were determined. Conclusion: The serum IgA RIs were established for three groups of Brazilian children aged 1-11 years, which differed from those currently applied in Brazilian pediatric practice and from those defined by international studies. This definition will help Brazilian pediatricians formulate an accurate diagnosis and facilitate decision-making.

Impact of Epstein-Barr virus co-infection on natural acquired Plasmodium vivax antibody response.

BACKGROUND: The simultaneous infection of Plasmodium falciparum and Epstein-Barr virus (EBV) could promote the development of the aggressive endemic Burkitt's Lymphoma (eBL) in children living in P. falciparum holoendemic areas. While it is well-established that eBL is not related to other human malaria parasites, the impact of EBV infection on the generation of human malaria immunity remains largely unexplored. Considering that this highly prevalent herpesvirus establishes a lifelong persistent infection on B-cells with possible influence on malaria immunity, we hypothesized that EBV co-infection could have impact on the naturally acquired antibody responses to P. vivax, the most widespread human malaria parasite. METHODOLOGY/PRINCIPAL FINDINGS: The study design involved three cross-sectional surveys at six-month intervals (baseline, 6 and 12 months) among long-term P. vivax exposed individuals living in the Amazon rainforest. The approach focused on a group of malaria-exposed individuals whose EBV-DNA (amplification of balf-5 gene) was persistently detected in the peripheral blood (PersVDNA, n = 27), and an age-matched malaria-exposed group whose EBV-DNA could never be detected during the follow-up (NegVDNA, n = 29). During the follow-up period, the serological detection of EBV antibodies to lytic/ latent viral antigens showed that IgG antibodies to viral capsid antigen (VCA-p18) were significantly different between groups (PersVDNA > NegVDNA). A panel of blood-stage P. vivax antigens covering a wide range of immunogenicity confirmed that in general PersVDNA group showed low levels of antibodies as compared with NegVDNA. Interestingly, more significant differences were observed to a novel DBPII immunogen, named DEKnull-2, which has been associated with long-term neutralizing antibody response. Differences between groups were less pronounced with blood-stage antigens (such as MSP1-19) whose levels can fluctuate according to malaria transmission. CONCLUSIONS/SIGNIFICANCE: In a proof-of-concept study we provide evidence that a persistent detection of EBV-DNA in peripheral blood of adults in a P. vivax semi-immune population may impact the long-term immune response to major malaria vaccine candidates.

Prevalence of molecular and serological tests of the new coronavirus (SARS-CoV-2) in Carlos Chagas laboratory - Sabin group in Cuiabá.

BACKGROUND: Coronavirus disease 2019, which is caused by the new severe acute respiratory syndrome coronavirus 2, became a pandemic in 2020 with a mortality rate of 2% and high transmissibility, thus making studies with an epidemiological profile essential. OBJECTIVES: The aim of this study was to characterize the population that performed the severe acute respiratory syndrome coronavirus 2 molecular and serological tests in Carlos Chagas Laboratory - Sabin Group in Cuiabá. METHODS: A retrospective cross-sectional study was carried out with all the samples collected from nasal swab tested by RT-PCR and serological for severe acute respiratory syndrome coronavirus 2 IgM/IgG from the population served between April and December 2020. FINDINGS: In the analysis period, 23,631 PCR-coronavirus disease 2019 examinations were registered. Of this total number of cases, 7,649 (32.37%) tested positive, while 15,982 (66.31%) did not detect viral RNA and 374 of the results as undetermined. The peak of positive RT-PCR performed in July (n=5,878), with 35.65% (n=2,096). A total of 8,884 tests were performed on serological test SOROVID-19, with a peak of 1,169 (57.16%) of the positive tests for severe acute respiratory syndrome coronavirus 2 in July. MAIN CONCLUSIONS: Molecular positivity and serological tests, both peaked in July 2020, were mostly present in women aged 20-59 years, characterizing Cuiabá as the epicenter of the Midwest region in this period due to the high rate of transmissibility of severe acute respiratory syndrome coronavirus 2.

Prevalence of molecular and serological tests of the new coronavirus (SARS-CoV-2) in Carlos Chagas laboratory - Sabin group in Cuiabá

SUMMARY BACKGROUND: Coronavirus disease 2019, which is caused by the new severe acute respiratory syndrome coronavirus 2, became a pandemic in 2020 with a mortality rate of 2% and high transmissibility, thus making studies with an epidemiological profile essential. OBJECTIVES: The aim of this study was to characterize the population that performed the severe acute respiratory syndrome coronavirus 2 molecular and serological tests in Carlos Chagas Laboratory - Sabin Group in Cuiabá. METHODS: A retrospective cross-sectional study was carried out with all the samples collected from nasal swab tested by RT-PCR and serological for severe acute respiratory syndrome coronavirus 2 IgM/IgG from the population served between April and December 2020. FINDINGS: In the analysis period, 23,631 PCR-coronavirus disease 2019 examinations were registered. Of this total number of cases, 7,649 (32.37%) tested positive, while 15,982 (66.31%) did not detect viral RNA and 374 of the results as undetermined. The peak of positive RT-PCR performed in July (n=5,878), with 35.65% (n=2,096). A total of 8,884 tests were performed on serological test SOROVID-19, with a peak of 1,169 (57.16%) of the positive tests for severe acute respiratory syndrome coronavirus 2 in July. MAIN CONCLUSIONS: Molecular positivity and serological tests, both peaked in July 2020, were mostly present in women aged 20-59 years, characterizing Cuiabá as the epicenter of the Midwest region in this period due to the high rate of transmissibility of severe acute respiratory syndrome coronavirus 2.