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1.
PLoS One ; 16(1): e0244937, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33406122

RESUMO

BACKGROUND: The impact of SARS-CoV-2 in regions endemic for both Dengue and Chikungunya is still not fully understood. Considering that symptoms/clinical features displayed during Dengue, Chikungunya and SARS-CoV-2 acute infections are similar, undiagnosed cases of SARS-CoV-2 in co-endemic areas may be more prevalent than expected. This study was conducted to assess the prevalence of covert cases of SARS-CoV-2 among samples from patients with clinical symptoms compatible with either Dengue or Chikungunya viral infection in the state of Espírito Santo, Brazil. METHODS: Presence of immunoglobulin G (IgG) antibody specific to SARS-CoV-2 nucleoprotein was detected using a chemiluminescent microparticle immunoassay in samples from 7,370 patients, without previous history of COVID-19 diagnosis, suspected of having either Dengue (n = 1,700) or Chikungunya (n = 7,349) from December 1st, 2019 to June 30th, 2020. FINDINGS: Covert cases of SARS-CoV-2 were detected in 210 (2.85%) out of the 7,370 serum samples tested. The earliest undiagnosed missed case of COVID-19 dated back to a sample collected on December 18, 2019, also positive for Dengue Virus. Cross-reactivity with either Dengue virus or other common coronaviruses were not observed. INTERPRETATION: Our findings demonstrate that concomitant Dengue or Chikungunya outbreaks may difficult the diagnosis of SARS-CoV-2 infections. To our knowledge, this is the first study to demonstrate, with a robust sample size (n = 7,370) and using highly specific and sensitive chemiluminescent microparticle immunoassay method, that covert SARS-CoV-2 infections are more frequent than previously expected in Dengue and Chikungunya hyperendemic regions. Moreover, our results suggest that SAR-CoV-2 cases were occurring prior to February, 2020, and that these undiagnosed missed cases may have contributed to the fast expansion of SARS-CoV-2 outbreak in Brazil. Data presented here demonstrate that in arboviral endemic regions, SARS-CoV-2 infection must be always considered, regardless of the existence of a previous positive diagnosis for Dengue or Chikungunya.


Assuntos
/epidemiologia , Febre de Chikungunya/epidemiologia , Dengue/epidemiologia , Adulto , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Vírus Chikungunya/patogenicidade , Coinfecção/epidemiologia , Vírus da Dengue/patogenicidade , Erros de Diagnóstico/tendências , Surtos de Doenças , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Prevalência , /patogenicidade
2.
J Infect Dis ; 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33319249

RESUMO

BACKGROUND: Takeda's dengue vaccine is under evaluation in an ongoing Phase 3 efficacy study; we present an update after 2 years. METHODS: 20,099 children (4-16 years old) were randomized to receive two doses of TAK-003 or placebo three months apart and are under long-term febrile surveillance to detect dengue by serotype-specific RT-PCR. (NCT02747927). RESULTS: Cumulative efficacy against dengue over ~27 months since first dose was 72.7% (95% CI: 67.1 - 77.3), which included efficacy of 67.0% (95% CI: 53.6 - 76.5) in dengue-naïve and 89.2% (82.4 - 93.3) against hospitalized dengue. In the second year after vaccination, a decline in efficacy was observed [56.2% (42.3 - 66.8)] with the largest decline in 4 - 5 year-old children [24.5% (-34.2 - 57.5)]; efficacy was 60.6% (43.8 - 72.4) in 6 - 11 year and 71.2% (41.0 - 85.9) in 12 - 16 year age groups. As TAK-003 efficacy varies by serotype, changes in serotype dominance partially contributed to the efficacy differences in year by year analysis. No related serious adverse events occurred during the second year. CONCLUSION: TAK-003 demonstrated continued benefit independent of baseline serostatus in reducing dengue with some decline in efficacy during the second year. Three-year data will be important to see if efficacy stabilizes or declines further.

4.
Pediatr Infect Dis J ; 39(10): 961-968, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32932330

RESUMO

BACKGROUND: We previously described an increased immune response 28 days after a booster dose of the live, attenuated, tetravalent dengue vaccine (CYD-TDV) in healthy adolescents and adults in Latin America (CYD64, NCT02623725). This follow-up study evaluated immune response persistence and safety of a CYD-TDV booster dose up to Month (M) 24 post-booster. METHODS: This study included 250 participants who previously received 3 primary doses of CYD-TDV in the CYD13 (NCT00993447) and CYD30 (NCT01187433) studies, and who were randomized 4-5 years later to receive a CYD-TDV booster or placebo (3:1). Dengue neutralizing antibodies against the parental dengue virus strains were assessed using the plaque reduction neutralization test (PRNT50) at M6, M12, and M24 post-booster. Post-booster memory B-cell responses were assessed in a subset of participants using the FluoroSpot assay up to M12 post-booster. RESULTS: In the CYD-TDV group (n = 187), dengue neutralizing antibody geometric mean titers (GMTs) declined from the peak at day 28 through to M24 for all serotypes. GMTs at M24 were similar to those at pre-booster among baseline dengue seropositives. A similar trend was observed for baseline dengue seronegatives, albeit at a lower magnitude. Previous vaccination-induced detectable B-cell memory responses in seropositives and seronegatives that decreased to pre-booster levels at M12 post-booster. The CYD-TDV booster dose was well-tolerated. CONCLUSIONS: In baseline dengue seropositives, following a CYD-TDV booster dose administered 4-5 years after primary immunization, dengue neutralizing antibody GMTs and B-cell memory responses peaked in the short-term before gradually decreasing over time. A CYD-TDV booster dose could improve protection against dengue during outbreak periods.

5.
Nat Commun ; 11(1): 4870, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978384

RESUMO

Little is known about the physiology of latent Mycobacterium tuberculosis infection. We studied the mutational rates of 24 index tuberculosis (TB) cases and their latently infected household contacts who developed active TB up to 5.25 years later, as an indication of bacterial physiological state and possible generation times during latent TB infection in humans. Here we report that the rate of new mutations in the M. tuberculosis genome decline dramatically after two years of latent infection (two-sided p < 0.001, assuming an 18 h generation time equal to log phase M. tuberculosis, with latency period modeled as a continuous variable). Alternatively, assuming a fixed mutation rate, the generation time increases over the latency duration. Mutations indicative of oxidative stress do not increase with increasing latency duration suggesting a lack of host or bacterial derived mutational stress. These results suggest that M. tuberculosis enters a quiescent state during latency, decreasing the risk for mutational drug resistance and increasing generation time, but potentially increasing bacterial tolerance to drugs that target actively growing bacteria.


Assuntos
Tuberculose Latente/microbiologia , Taxa de Mutação , Mycobacterium tuberculosis/genética , Tuberculose/microbiologia , Adulto , Brasil , DNA Bacteriano/isolamento & purificação , Feminino , Genoma Bacteriano , Humanos , Masculino , Mutação , Mycobacterium tuberculosis/patogenicidade , Estresse Oxidativo , Filogenia , Polimorfismo de Nucleotídeo Único , Fatores de Tempo , Adulto Jovem
6.
Tuberculosis (Edinb) ; 124: 101945, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32692652

RESUMO

This study aimed to evaluate the dynamics of culture filtrate dependent subpopulations of Mycobacterium tuberculosis in a prospective cohort study following 17 patients through a standard 6-month anti-tuberculosis regimen, performing monthly sputum collection. We performed the limiting dilution method with culture filtrate supplementation of liquid media in pre- and post-treatment sputum samples to assess the bacillary load and to evaluate the Mycobacterium tuberculosis subpopulation dynamics within the 6-months standard anti-tuberculosis regimen. We found that supplementation increased the bacillary load by 30% in pre-treatment samples (p = 0.0005) and 35% in samples after one month of treatment (p = 0.0977). We found a weak linear correlation between the decrease of Mycobacterium tuberculosis growth in liquid media with and without culture filtrate supplementation (ρ = 0.54; p = 0.026). None of the patients had bacilli recovery after two months of treatment. Our study constitutes the first follow-up regarding Mycobacterium tuberculosis subpopulation dynamics throughout a standard 6-month anti-tuberculosis treatment and also supports the use of culture filtrate to increase bacillary load in liquid media. Moreover, it highlights that any new treatment regimens should test the efficacy of the drugs in all Mycobacterium tuberculosis subpopulations.

7.
Am J Epidemiol ; 189(11): 1421-1426, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-32458995

RESUMO

Serial interval (SI), defined as the time between symptom onset in an infector and infectee pair, is commonly used to understand infectious diseases transmission. Slow progression to active disease, as well as the small percentage of individuals who will eventually develop active disease, complicate the estimation of the SI for tuberculosis (TB). In this paper, we showed via simulation studies that when there is credible information on the percentage of those who will develop TB disease following infection, a cure model, first introduced by Boag in 1949, should be used to estimate the SI for TB. This model includes a parameter in the likelihood function to account for the study population being composed of those who will have the event of interest and those who will never have the event. We estimated the SI for TB to be approximately 0.5 years for the United States and Canada (January 2002 to December 2006) and approximately 2.0 years for Brazil (March 2008 to June 2012), which might imply a higher occurrence of reinfection TB in a developing country like Brazil.

8.
Tuberculosis (Edinb) ; 120: 101898, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-32090859

RESUMO

The goal of this study was to identify individuals at risk of progression and reactivation among household contacts (HHC) of pulmonary TB cases in Vitoria, Brazil. We first evaluated the predictive performance of six published signatures on the transcriptional dataset obtained from peripheral blood mononuclear cell samples from HHC that either progressed to TB disease or not (non-progressors) during a five-year follow-up. The area under the curve (AUC) values for the six signatures ranged from 0.670 to 0.461, and the PPVs did not reach the WHO published target product profiles (TPPs). We therefore used as training cohort the earliest time-point samples from the African cohort of adolescents (GSE79362) and applied an ensemble feature selection pipeline to derive a novel 29-gene signature (PREDICT29). PREDICT29 was tested on 16 progressors and 21 non-progressors. PREDICT29 performed better in segregating progressors from non-progressors in the Brazil cohort with the area under the curve (AUC) value of 0.911 and PPV of 20%. This proof of concept study demonstrates that PREDICT29 can predict risk of progression/reactivation to clinical TB disease in recently exposed individuals at least 5 years prior to disease development. Upon validation in larger and geographically diverse cohorts, PREDICT29 can be used to risk-stratify recently infected for targeted therapy.

9.
Immunology ; 159(4): 429-440, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31925782

RESUMO

Cytotoxic activity mediated by CD8+ T cells is the main signature of the immunopathogenesis of cutaneous leishmaniasis (CL). Here, we performed a broad evaluation of natural killer (NK) cell phenotypic and functional features during cutaneous leishmaniasis. We demonstrate for the first time that CL patients present the accumulation of circulating NK cells with multiple features of replicative senescence including low proliferative capacity and shorter telomeres, elevated expression of CD57, KLRG1 but diminished CD27 stimulatory receptor expression. Moreover, they exhibited higher cytotoxic and inflammatory potential than age-matched controls. The accumulation of circulating senescent NK cells (CD56dim  CD57bright ) correlated positively with skin lesion size in the same patients, suggesting that they, like circulating senescent CD8+ T cells, may contribute to the immunopathology of CL. However, this senescent population had lower cutaneous lymphocyte antigen expression and so had diminished skin-homing potential compared with total or senescent CD8+ T cells. This was confirmed in CL skin lesions where we found a predominance of CD8+ T cells (both senescent and non-senescent) that correlated with the severity of the disease. Although there was also a correlation between the proportions of senescent NK cells (CD56+  CD57+ ) in the skin and lesion size, this was less evident. Collectively our results demonstrate first-hand that senescent cytotoxic cells may mediate skin pathology during human cutaneous leishmaniasis. However, as senescent cytotoxic CD8+ T cells predominate in the skin lesions, they may have a greater role than NK cells in mediating the non-specific skin damage in CL.


Assuntos
Citotoxicidade Imunológica , Células Matadoras Naturais/patologia , Leishmania braziliensis/patogenicidade , Leishmaniose Cutânea/patologia , Pele/patologia , Linfócitos T Citotóxicos/patologia , Antígeno CD56/genética , Antígeno CD56/imunologia , Antígenos CD57/genética , Antígenos CD57/imunologia , Estudos de Casos e Controles , Senescência Celular/imunologia , Feminino , Regulação da Expressão Gênica , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Lectinas Tipo C/genética , Lectinas Tipo C/imunologia , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Masculino , Oligossacarídeos/genética , Oligossacarídeos/imunologia , Receptores Imunológicos/genética , Receptores Imunológicos/imunologia , Índice de Gravidade de Doença , Antígeno Sialil Lewis X/análogos & derivados , Antígeno Sialil Lewis X/genética , Antígeno Sialil Lewis X/imunologia , Transdução de Sinais , Pele/imunologia , Pele/parasitologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/parasitologia
10.
N Engl J Med ; 381(21): 2009-2019, 2019 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-31693803

RESUMO

BACKGROUND: Dengue, a mosquito-borne viral disease, was designated a World Health Organization top 10 threat to global health in 2019. METHODS: We present primary efficacy data from part 1 of an ongoing phase 3 randomized trial of a tetravalent dengue vaccine candidate (TAK-003) in regions of Asia and Latin America in which the disease is endemic. Healthy children and adolescents 4 to 16 years of age were randomly assigned in a 2:1 ratio (stratified according to age category and region) to receive two doses of vaccine or placebo 3 months apart. Participants presenting with febrile illness were tested for virologically confirmed dengue by serotype-specific reverse-transcriptase polymerase chain reaction. The primary end point was overall vaccine efficacy in preventing virologically confirmed dengue caused by any dengue virus serotype. RESULTS: Of the 20,071 participants who were given at least one dose of vaccine or placebo (safety population), 19,021 (94.8%) received both injections and were included in the per-protocol analysis. The overall vaccine efficacy in the safety population was 80.9% (95% confidence interval [CI], 75.2 to 85.3; 78 cases per 13,380 [0.5 per 100 person-years] in the vaccine group vs. 199 cases per 6687 [2.5 per 100 person-years] in the placebo group). In the per-protocol analyses, vaccine efficacy was 80.2% (95% CI, 73.3 to 85.3; 61 cases of virologically confirmed dengue in the vaccine group vs. 149 cases in the placebo group), with 95.4% efficacy against dengue leading to hospitalization (95% CI, 88.4 to 98.2; 5 hospitalizations in the vaccine group vs. 53 hospitalizations in the placebo group). Planned exploratory analyses involving the 27.7% of the per-protocol population that was seronegative at baseline showed vaccine efficacy of 74.9% (95% CI, 57.0 to 85.4; 20 cases of virologically confirmed dengue in the vaccine group vs. 39 cases in the placebo group). Efficacy trends varied according to serotype. The incidence of serious adverse events was similar in the vaccine group and placebo group (3.1% and 3.8%, respectively). CONCLUSIONS: TAK-003 was efficacious against symptomatic dengue in countries in which the disease is endemic. (Funded by Takeda Vaccines; TIDES ClinicalTrials.gov number, NCT02747927.).


Assuntos
Vacinas contra Dengue/imunologia , Vírus da Dengue/imunologia , Dengue/prevenção & controle , Doenças Endêmicas/prevenção & controle , Adolescente , América/epidemiologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Ásia/epidemiologia , Criança , Pré-Escolar , Dengue/epidemiologia , Dengue/imunologia , Vacinas contra Dengue/efeitos adversos , Vírus da Dengue/isolamento & purificação , Método Duplo-Cego , Feminino , Humanos , Incidência , Masculino , Sorogrupo , Resultado do Tratamento
11.
PLoS One ; 14(10): e0223966, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31639145

RESUMO

Household contact studies of tuberculosis (TB) are a common way to study disease transmission dynamics. However these studies lack a mechanism for accounting for community transmission, which is known to be significant, particularly in high burden settings. We illustrate a statistical approach for estimating both the correlates with transmission of TB in a household setting and the probability of community transmission using a modified Bayesian mixed-effects model. This is applied to two household contact studies in Vitória, Brazil from 2008-2013 and Kampala, Uganda from 1995-2004 that enrolled households with an individual that was recently diagnosed with pulmonary TB. We estimate the probability of community transmission to be higher in Uganda (ranging from 0.21 to 0.69, depending on HHC age and HIV status of the index case) than in Brazil (ranging from 0.13 for young children to 0.50 in adults). These estimates are consistent with a higher overall burden of disease in Uganda compared to Brazil. Our method also estimates an increasing risk of community-acquired TB with age of the household contact, consistent with existing literature. This approach is a useful way to integrate the role of the community in understanding TB disease transmission dynamics in household contact studies.


Assuntos
Teorema de Bayes , Busca de Comunicante/métodos , Características da Família , Modelos Estatísticos , Mycobacterium tuberculosis/isolamento & purificação , Tuberculose Pulmonar/epidemiologia , Adolescente , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Fatores de Risco , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/microbiologia , Uganda/epidemiologia
12.
PLoS Negl Trop Dis ; 13(8): e0007648, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31449521

RESUMO

Zika virus (ZIKV) is a newly-identified infectious cause of congenital disease. Transplacental transfer of maternal IgG to the fetus plays an important role in preventing many neonatal infections. However, antibody transfer may also have negative consequences, such as mediating enhancement of flavivirus infections in early life, or trafficking of virus immune complexes to the fetal compartment. ZIKV infection produces placental pathology which could lead to impaired IgG transfer efficiency as occurs in other maternal infections, such as HIV-1 and malaria. In this study, we asked whether ZIKV infection during pregnancy impairs transplacental transfer of IgG. We enrolled pregnant women with fever or rash in a prospective cohort in Vitoria, Brazil during the recent ZIKV epidemic. ZIKV and dengue virus (DENV)-specific IgG, ZIKV and DENV neutralizing antibodies, and routine vaccine antigen-specific IgG were measured in maternal samples collected around delivery and 20 paired cord blood samples. We concluded that 8 of these mothers were infected with ZIKV during pregnancy and 12 were ZIKV-uninfected. The magnitude of flavivirus-specific IgG, neutralizing antibody, and vaccine-elicited IgG were highly correlated between maternal plasma and infant cord blood in both ZIKV-infected and -uninfected mother-infant pairs. Moreover, there was no difference in the magnitude of plasma flavivirus-specific IgG levels between mothers and infants regardless of ZIKV infection status. Our data suggests that maternal ZIKV infection during pregnancy does not impair the efficiency of placental transfer of flavivirus-specific, functional, and vaccine-elicited IgG. These findings have implications for the neonatal outomes of maternal ZIKV infection and optimal administration of antibody-based ZIKV vaccines and therapeutics.


Assuntos
Anticorpos Antivirais/sangue , Sangue Fetal/imunologia , Imunoglobulina G/sangue , Complicações Infecciosas na Gravidez/imunologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Adolescente , Adulto , Anticorpos Neutralizantes/sangue , Brasil , Vírus da Dengue/imunologia , Feminino , Humanos , Gravidez , Estudos Prospectivos , Adulto Jovem
13.
Am J Trop Med Hyg ; 101(4): 789-794, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31436148

RESUMO

In India, visceral leishmaniasis (VL) caused by Leishmania donovani has been successfully treated with miltefosine with a cure rate of > 90%. To assess the efficacy and safety of oral miltefosine against Brazilian VL, which is caused by Leishmania infantum, a phase II, open-label, dose-escalation study of oral miltefosine was conducted in children (aged 2-12 years) and adolescent-adults (aged 13-60 years). Definitive cure was assessed at a 6-month follow-up visit. The cure rate was only 42% (6 of 14 patients) with a recommended treatment of 28 days and 68% (19 of 28 patients) with an extended treatment of 42 days. The in vitro miltefosine susceptibility profile of intracellular amastigote stages of the pretreatment isolates, from cured and relapsed patients, showed a positive correlation with the clinical outcome. The IC50 mean (SEM) of eventual cures was 5.1 (0.4) µM, whereas that of eventual failures was 12.8 (1.9) µM (P = 0.0002). An IC50 above 8.0 µM predicts failure with 82% sensitivity and 100% specificity. The finding of L. infantum amastigotes resistant to miltefosine in isolates from patients who eventually failed treatment strongly suggests natural resistance to this drug, as miltefosine had never been used in Brazil before this trial was carried out.


Assuntos
Antiprotozoários/administração & dosagem , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Fosforilcolina/análogos & derivados , Adolescente , Adulto , Brasil/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Imunidade Inata , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/parasitologia , Masculino , Pessoa de Meia-Idade , Fosforilcolina/administração & dosagem , Falha de Tratamento , Adulto Jovem
14.
Tuberculosis (Edinb) ; 118: 101859, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31434026

RESUMO

Biomarkers for TB treatment response and outcome are needed. This study characterize changes in immune profiles during TB treatment, define biosignatures associated with treatment outcomes, and explore the feasibility of predictive models for relapse. Seventy-two markers were measured by multiplex cytokine array in serum samples from 78 cured, 12 relapsed and 15 failed treatment patients from South Africa before and during therapy for pulmonary TB. Promising biosignatures were evaluated in a second cohort from Uganda/Brazil consisting of 17 relapse and 23 cured patients. Thirty markers changed significantly with different response patterns during TB treatment in cured patients. The serum biosignature distinguished cured from relapse patients and a combination of two clinical (time to positivity in liquid culture and BMI) and four immunological parameters (TNF-ß, sIL-6R, IL-12p40 and IP-10) at diagnosis predicted relapse with a 75% sensitivity (95%CI 0.38-1) and 85% specificity (95%CI 0.75-0.93). This biosignature was validated in an independent Uganda/Brazil cohort correctly classifying relapse patients with 83% (95%CI 0.58-1) sensitivity and 61% (95%CI 0.39-0.83) specificity. A characteristic biosignature with value as predictor of TB relapse was identified. The repeatability and robustness of these biomarkers require further validation in well-characterized cohorts.


Assuntos
Antituberculosos/uso terapêutico , Biomarcadores/sangue , Tuberculose Pulmonar/tratamento farmacológico , Adulto , Citocinas/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prognóstico , Curva ROC , Recidiva , Falha de Tratamento , Resultado do Tratamento , Tuberculose Pulmonar/diagnóstico , Tuberculose Pulmonar/imunologia
15.
Open Forum Infect Dis ; 6(6): ofz184, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31205972

RESUMO

Background: Epidemiologic data suggests that only a minority of tuberculosis (TB) patients are infectious. Cough aerosol sampling is a novel quantitative method to measure TB infectiousness. Methods: We analyzed data from three studies conducted in Uganda and Brazil over a 13-year period. We included sputum acid fast bacilli (AFB) and culture positive pulmonary TB patients and used a cough aerosol sampling system (CASS) to measure the number of colony-forming units (CFU) of Mycobacterium tuberculosis in cough-generated aerosols as a measure for infectiousness. Aerosol data was categorized as: aerosol negative (CFU = 0) and aerosol positive (CFU > 0). Logistic regression models were built to identify factors associated with aerosol positivity. Results: M. tuberculosis was isolated by culture from cough aerosols in 100/233 (43%) TB patients. In an unadjusted analysis, aerosol positivity was associated with fewer days of antituberculous therapy before CASS sampling (p = .0001), higher sputum AFB smear grade (p = .01), shorter days to positivity in liquid culture media (p = .02), and larger sputum volume (p = .03). In an adjusted analysis, only fewer days of TB treatment (OR 1.47 per 1 day of therapy, 95% CI 1.16-1.89; p = .001) was associated with aerosol positivity. Conclusion: Cough generated aerosols containing viable M. tuberculosis, the infectious moiety in TB, are detected in a minority of TB patients and rapidly become non-culturable after initiation of antituberculous treatment. Mechanistic studies are needed to further elucidate these findings.

16.
Pediatr Infect Dis J ; 38(5): e90-e95, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30986790

RESUMO

BACKGROUND: The tetravalent dengue vaccine (CYD-TDV, Dengvaxia, Sanofi Pasteur) demonstrated efficacy in 2 previous phase III trials conducted in endemic countries. Neutralizing antibodies (NAbs) elicited by 3 doses of this vaccine have been associated with efficacy. Long-term follow-up data has shown that NAb immune responses tend to wane over time, after the third dose. This study compared the immune response elicited by a booster (4th) dose of CYD-TDV with the immune responses from the same participants obtained post-dose 3 of the primary series administered 4-5 years earlier. METHODS: This multicenter, observer-blind, randomized, placebo-controlled, phase II noninferiority trial was conducted in healthy adolescents and adults in dengue endemic countries of Latin America (Colombia, Honduras, Brazil, Mexico and Puerto Rico). All participants had been immunized with 3 doses of CYD-TDV in phase II studies conducted 4-5 years earlier. NAb levels against each dengue virus serotype 28 days postbooster or placebo injection were reported. RESULTS: A total of 187 participants received CYD-TDV and 64 received placebo. Prospectively defined noninferiority criteria for dengue NAbs after the booster dose compared with postdose 3 were met for all 4 serotypes. Prospectively defined superiority criteria were met for 3 of the 4 serotypes. CONCLUSIONS: Antidengue NAb levels can be boosted to levels at least as high as, or higher than those observed after completion of the primary 3-dose series, with an additional dose of CYD-TDV 4-5 years after the standard 3-dose vaccination schedule.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Formação de Anticorpos , Vacinas contra Dengue/imunologia , Vírus da Dengue/imunologia , Dengue/prevenção & controle , Imunização Secundária , Adolescente , Vacinas contra Dengue/administração & dosagem , Feminino , Voluntários Saudáveis , Humanos , América Latina , Masculino , Placebos/administração & dosagem , Método Simples-Cego , Adulto Jovem
17.
Tuberculosis (Edinb) ; 116: 1-7, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30983569

RESUMO

BACKGROUND: Rapid diagnosis of pulmonary tuberculosis (TB) is critical to TB control. However, many patients with paucibacillary TB disease remain undiagnosed. Current TB elimination goals require new tools to diagnose early disease. We evaluated performance of the Totally Optimized PCR (TOP) TB assay, a novel ultrasensitive molecular test. METHODS: We assessed analytical specificity against nontuberculous mycobacteria (NTM), and estimated the diagnostic accuracy of TOP in a pilot study in Brazil (n = 46) and a cross-sectional study in Boston (n = 60). We compared TOP results to culture and a composite reference standard (CRS). RESULTS: TOP exhibited no cross-reactivity against NTM. We tested 132 respiratory specimens from 106 patients with suspected pulmonary TB. The pilot demonstrated feasibility and 100% (95% CI 85-100) sensitivity in predominantly smear-positive specimens; TOP's specificity against solid media culture was low (58%, 37-77) but improved against a CRS (93%, 68-100). Similarly, when using the CRS in the Boston study, TOP (88%, 1-99) had greater sensitivity than solid or liquid media culture (25%, 3-65) and similar specificity (both 100%, 93-100). CONCLUSIONS: The TOP assay enables detection of M. tuberculosis in culture-negative paucibacillary disease. While the use of TOP for the diagnosis of paucibacillary disease will require further clinical validation, its high sensitivity indicate a more immediate utility as a rule out TB test.


Assuntos
Técnicas Bacteriológicas , DNA Bacteriano/genética , Mycobacterium tuberculosis/genética , Reação em Cadeia da Polimerase , Escarro/microbiologia , Tuberculose Pulmonar/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Boston , Brasil , Estudos Transversais , DNA Bacteriano/isolamento & purificação , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/isolamento & purificação , Projetos Piloto , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Tuberculose Pulmonar/microbiologia , Fluxo de Trabalho , Adulto Jovem
18.
Microbes Infect ; 21(7): 328-335, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30817996

RESUMO

The use of adjuvants in vaccine formulations is a well-established practice to improve immunogenicity and protective immunity against diseases. Previously, we have demonstrated the feasibility of intranasal vaccination with the antigen of killed Leishmania amazonensis promastigotes (LaAg) against experimental leishmaniasis. In this work, we sought to optimize the immunogenic effect and protective immunity against murine visceral leishmaniasis conferred by intranasal delivery of LaAg in combination with a synthetic TLR1/TLR2 agonist (Pam3CSK4). Intranasal vaccination with LaAg/PAM did not show toxicity or adverse effects, induced the increase of delayed-type hypersensitivity response and the production of inflammatory cytokines after parasite antigen recall. However, mice vaccinated with LaAg/PAM and challenged with Leishmania infantum presented significant reduction of parasite burden in both liver and spleen, similar to those vaccinated with LaAg. Although LaAg/PAM intranasal vaccination had induced higher frequencies of specific CD4+ and CD8+ T cells and increased levels of IgG2a antibody isotype in serum, both LaAg and LaAg/PAM groups presented similar levels of IL-4 and IFN-y and decreased production of IL-10 when compared to controls. Our results provide the first evidence of the feasibility of intranasal immunization with antigens of killed Leishmania in association with a TLR agonist, which may be explored for developing an effective and alternative strategy for vaccination against visceral leishmaniasis.


Assuntos
Antígenos de Protozoários/imunologia , Leishmania/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/imunologia , Lipopeptídeos/imunologia , Adjuvantes Imunológicos/administração & dosagem , Administração Intranasal , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/administração & dosagem , Citocinas/sangue , Feminino , Vacinas contra Leishmaniose/administração & dosagem , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/prevenção & controle , Lipopeptídeos/administração & dosagem , Fígado/metabolismo , Fígado/parasitologia , Linfócitos/imunologia , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Baço/metabolismo , Baço/parasitologia , Vacinação
19.
PLoS Pathog ; 15(3): e1007613, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30840702

RESUMO

In a study of household contacts (HHC), households were categorized into High (HT) and Low (LT) transmission groups based on the proportion of HHC with a positive tuberculin skin test. The Mycobacterium tuberculosis (Mtb) strains from HT and LT index cases of the households were designated Mtb-HT and Mtb-LT, respectively. We found that C3HeB/FeJ mice infected with Mtb-LT strains exhibited significantly higher bacterial burden compared to Mtb-HT strains and also developed diffused inflammatory lung pathology. In stark contrast, a significant number of mice infected with Mtb-HT strains developed caseating granulomas, a lesion type with high potential to cavitate. None of the Mtb-HT infected animals developed diffused inflammatory lung pathology. A link was observed between increased in vitro replication of Mtb-LT strains and their ability to induce significantly high lipid droplet formation in macrophages. These results support that distinct early interactions of Mtb-HT and Mtb-LT strains with macrophages and subsequent differential trajectories in pathological disease may be the mechanism underlying their transmission potential.


Assuntos
Mycobacterium tuberculosis/metabolismo , Tuberculose Pulmonar/transmissão , Virulência/genética , Animais , Modelos Animais de Doenças , Transmissão de Doença Infecciosa , Feminino , Granuloma , Pulmão/patologia , Macrófagos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidade , Fenótipo , Tuberculose/etiologia , Tuberculose Pulmonar/etiologia , Virulência/fisiologia
20.
PLoS One ; 13(10): e0206384, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30372480

RESUMO

BACKGROUND: Mycobacterium tuberculosis cultures of cough-generated aerosols from patients with pulmonary tuberculosis (TB) are a quantitative method to measure infectiousness and to predict secondary outcomes in exposed contacts. However, their reproducibility has not been established. OBJECTIVE: To evaluate the predictive value of colony-forming units (CFU) of M. tuberculosis in cough aerosols on secondary infection and disease in household contacts in Brazil. METHODS: Adult sputum smear+ and culture+ pulmonary TB cases underwent a standard evaluation and were categorized according to aerosol CFU. We evaluated household contacts for infection at baseline and at 8 weeks with TST and IGRA, and secondary disease. RESULTS: We enrolled 48 index TB cases; 40% had negative aerosols, 27% low aerosols (<10 CFU) and 33% high aerosols (≥10 CFU). Of their 230 contacts, the proportion with a TST ≥10 mm at 8 weeks was 59%, 65% and 75%, respectively (p = 0.34). Contacts of high aerosol cases had greater IGRA readouts (median 4.6 IU/mL, IQR 0.02-10) when compared to those with low (0.8, 0.2-10) or no aerosol (0.1, 0-3.7; p = 0.08). IGRA readouts in TST converters of high aerosol cases (median 20 IU/mL, IQR 10-24) were larger than those from aerosol-negative (0.13, 0.04-3; p = o.o2). 8/9 (89%) culture+ secondary TB cases occurred in contacts of aerosol+ cases. CONCLUSION: Aerosol CFU predicts quantitatively IGRA readouts among household contacts of smear positive TB cases. Our results strengthen the argument of using cough aerosols to guide targeted preventive treatment strategies, a necessary component of current TB elimination projections.


Assuntos
Tosse/microbiologia , Habitação , Mycobacterium tuberculosis/fisiologia , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/transmissão , Adulto , Aerossóis , Brasil , Técnicas de Cultura , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mycobacterium tuberculosis/crescimento & desenvolvimento , Valor Preditivo dos Testes
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