Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 443
Filtrar
1.
Sci Rep ; 14(1): 10842, 2024 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-38735993

RESUMO

Yellow fever outbreaks are prevalent, particularly in endemic regions. Given the lack of an established treatment for this disease, significant attention has been directed toward managing this arbovirus. In response, we developed a multiepitope vaccine designed to elicit an immune response, utilizing advanced immunoinformatic and molecular modeling techniques. To achieve this, we predicted B- and T-cell epitopes using the sequences from all structural (E, prM, and C) and nonstructural proteins of 196 YFV strains. Through comprehensive analysis, we identified 10 cytotoxic T-lymphocyte (CTL) and 5T-helper (Th) epitopes that exhibited overlap with B-lymphocyte epitopes. These epitopes were further evaluated for their affinity to a wide range of human leukocyte antigen system alleles and were rigorously tested for antigenicity, immunogenicity, allergenicity, toxicity, and conservation. These epitopes were linked to an adjuvant ( ß -defensin) and to each other using ligands, resulting in a vaccine sequence with appropriate physicochemical properties. The 3D structure of this sequence was created, improved, and quality checked; then it was anchored to the Toll-like receptor. Molecular Dynamics and Quantum Mechanics/Molecular Mechanics simulations were employed to enhance the accuracy of docking calculations, with the QM portion of the simulations carried out utilizing the density functional theory formalism. Moreover, the inoculation model was able to provide an optimal codon sequence that was inserted into the pET-28a( +) vector for in silico cloning and could even stimulate highly relevant humoral and cellular immunological responses. Overall, these results suggest that the designed multi-epitope vaccine can serve as prophylaxis against the yellow fever virus.


Assuntos
Epitopos de Linfócito T , Vacina contra Febre Amarela , Febre Amarela , Vírus da Febre Amarela , Vacina contra Febre Amarela/imunologia , Vírus da Febre Amarela/imunologia , Vírus da Febre Amarela/genética , Humanos , Febre Amarela/prevenção & controle , Febre Amarela/imunologia , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito B/imunologia , Vacinologia/métodos , Modelos Moleculares , Desenvolvimento de Vacinas , Simulação de Dinâmica Molecular , Linfócitos T Citotóxicos/imunologia
2.
Microbiol Spectr ; 12(5): e0370323, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38511952

RESUMO

Between 2016 and 2018, Brazil experienced major sylvatic yellow fever (YF) outbreaks that caused hundreds of casualties, with Minas Gerais (MG) being the most affected state. These outbreaks provided a unique opportunity to assess the immune response triggered by the wild-type (WT) yellow fever virus (YFV) in humans. The plaque reduction neutralization test (PRNT) is currently the standard method to assess the humoral immune response to YFV by measuring neutralizing antibodies (nAbs). The present study aimed to evaluate the humoral immune response of patients from the 2017-2018 sylvatic YF outbreak in MG with different disease outcomes by using PRNTs with a WT YFV strain, isolated from the 2017-2018 outbreak, and a vaccine YFV strain. Samples from naturally infected YF patients were tested, in comparison with healthy vaccinees. Results showed that both groups presented different levels of nAb against the WT and vaccine strains, and the levels of neutralization against the strains varied homotypically and heterotypically. Results based on the geometric mean titers (GMTs) suggest that the humoral immune response after a natural infection of YFV can reach higher levels than that induced by vaccination (GMT of patients against WT YFV compared to GMT of vaccinees, P < 0.0001). These findings suggest that the humoral immune responses triggered by the vaccine and WT strains of YFV are different, possibly due to genetic and antigenic differences between these viruses. Therefore, current means of assessing the immune response in naturally infected YF individuals and immunological surveillance methods in areas with intense viral circulation may need to be updated.IMPORTANCEYellow fever is a deadly febrile disease caused by the YFV. Despite the existence of effective vaccines, this disease still represents a public health concern worldwide. Much is known about the immune response against the vaccine strains of the YFV, but recent studies have shown that it differs from that induced by WT strains. The extent of this difference and the mechanisms behind it are still unclear. Thus, studies aimed to better understand the immune response against this virus are relevant and necessary. The present study evaluated levels of neutralizing antibodies of yellow fever patients from recent outbreaks in Brazil, in comparison with healthy vaccinees, using plaque reduction neutralization tests with WT and vaccine YFV strains. Results showed that the humoral immune response in naturally infected patients was higher than that induced by vaccination, thus providing new insights into the immune response triggered against these viruses.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Surtos de Doenças , Imunidade Humoral , Vacina contra Febre Amarela , Febre Amarela , Vírus da Febre Amarela , Febre Amarela/imunologia , Febre Amarela/epidemiologia , Febre Amarela/virologia , Humanos , Brasil/epidemiologia , Vírus da Febre Amarela/imunologia , Vírus da Febre Amarela/genética , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Masculino , Vacina contra Febre Amarela/imunologia , Feminino , Adulto , Pessoa de Meia-Idade , Vacinação , Testes de Neutralização , Adulto Jovem , Idoso , Adolescente
3.
Nat Commun ; 15(1): 1236, 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38336944

RESUMO

The mosquito-borne disease, Yellow fever (YF), has been largely controlled via mass delivery of an effective vaccine and mosquito control interventions. However, there are warning signs that YF is re-emerging in both Sub-Saharan Africa and South America. Imported from Africa in slave ships, YF was responsible for devastating outbreaks in the Caribbean. In Martinique, the last YF outbreak was reported in 1908 and the mosquito Aedes aegypti was incriminated as the main vector. We evaluated the vector competence of fifteen Ae. aegypti populations for five YFV genotypes (Bolivia, Ghana, Nigeria, Sudan, and Uganda). Here we show that mosquito populations from the Caribbean and the Americas were able to transmit the five YFV genotypes, with YFV strains for Uganda and Bolivia having higher transmission success. We also observed that Ae. aegypti populations from Martinique were more susceptible to YFV infection than other populations from neighboring Caribbean islands, as well as North and South America. Our vector competence data suggest that the threat of re-emergence of YF in Martinique and the subsequent spread to Caribbean nations and beyond is plausible.


Assuntos
Aedes , Febre Amarela , Animais , Humanos , Vírus da Febre Amarela/genética , Mosquitos Vetores , Índias Ocidentais , Região do Caribe/epidemiologia , Uganda
4.
Acta Trop ; 251: 107110, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38163515

RESUMO

Yellow Fever (YF) is a viral arbovirosis of Public Health importance. In Brazil, surveillance is focused mainly on detecting epizootic events of Platyrrhini. Herein, we compared the detection and phylogenetic analysis of YF virus in two neotropical primates (NTP), a Callithrix detected in the previous epidemic period (2016-2020), and a Callicebus nigrifons, showing a new introduction of YF in 2023. This paper illustrates the importance of joint actions of laboratory and field teams to ensure quick response to Public Health emergencies, such as the intensification of vaccination of susceptible human populations.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Animais , Humanos , Vírus da Febre Amarela/genética , Filogenia , Brasil/epidemiologia , Febre Amarela/epidemiologia , Febre Amarela/prevenção & controle , Callithrix , Surtos de Doenças
6.
Viruses ; 15(10)2023 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-37896790

RESUMO

Yellow Fever (YF) is a severe disease that, while preventable through vaccination, lacks rapid intervention options for those already infected. There is an urgent need for passive immunization techniques using YF-virus-like particles (YF-VLPs). To address this, we successfully established a bioreactor-based production process for YF-VLPs, leveraging transient transfection and integrating Process Analytical Technology. A cornerstone of this approach was the optimization of plasmid DNA (pDNA) production to a yield of 11 mg/L using design of experiments. Glucose, NaCl, yeast extract, and a phosphate buffer showed significant influence on specific pDNA yield. The preliminary work for VLP-production in bioreactor showed adjustments to the HEK cell density, the polyplex formation duration, and medium exchanges effectively elevated transfection efficiencies. The additive Pluronic F-68 was neutral in its effects, and anti-clumping agents (ACA) adversely affected the transfection process. Finally, we established the stirred-tank bioreactor process with integrated dielectric spectroscopy, which gave real-time insight in relevant process steps, e.g., cell growth, polyplex uptake, and harvest time. We confirmed the presence and integrity of YF-VLP via Western blot, imaging flow cytometry measurement, and transmission electron microscopy. The YF-VLP production process can serve as a platform to produce VLPs as passive immunizing agents against other neglected tropical diseases.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Humanos , Vírus da Febre Amarela/genética , Transfecção , Tecnologia , Reatores Biológicos
7.
Sci Adv ; 9(35): eadg9204, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37656782

RESUMO

Despite the considerable morbidity and mortality of yellow fever virus (YFV) infections in Brazil, our understanding of disease outbreaks is hampered by limited viral genomic data. Here, through a combination of phylogenetic and epidemiological models, we reconstructed the recent transmission history of YFV within different epidemic seasons in Brazil. A suitability index based on the highly domesticated Aedes aegypti was able to capture the seasonality of reported human infections. Spatial modeling revealed spatial hotspots with both past reporting and low vaccination coverage, which coincided with many of the largest urban centers in the Southeast. Phylodynamic analysis unraveled the circulation of three distinct lineages and provided proof of the directionality of a known spatial corridor that connects the endemic North with the extra-Amazonian basin. This study illustrates that genomics linked with eco-epidemiology can provide new insights into the landscape of YFV transmission, augmenting traditional approaches to infectious disease surveillance and control.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Humanos , Vírus da Febre Amarela/genética , Filogenia , Brasil/epidemiologia , Febre Amarela/epidemiologia , Surtos de Doenças , Genômica
8.
Lancet Microbe ; 4(9): e711-e721, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37544313

RESUMO

BACKGROUND: In 2021, four patients who had received solid organ transplants in the USA developed encephalitis beginning 2-6 weeks after transplantation from a common organ donor. We describe an investigation into the cause of encephalitis in these patients. METHODS: From Nov 7, 2021, to Feb 24, 2022, we conducted a public health investigation involving 15 agencies and medical centres in the USA. We tested various specimens (blood, cerebrospinal fluid, intraocular fluid, serum, and tissues) from the organ donor and recipients by serology, RT-PCR, immunohistochemistry, metagenomic next-generation sequencing, and host gene expression, and conducted a traceback of blood transfusions received by the organ donor. FINDINGS: We identified one read from yellow fever virus in cerebrospinal fluid from the recipient of a kidney using metagenomic next-generation sequencing. Recent infection with yellow fever virus was confirmed in all four organ recipients by identification of yellow fever virus RNA consistent with the 17D vaccine strain in brain tissue from one recipient and seroconversion after transplantation in three recipients. Two patients recovered and two patients had no neurological recovery and died. 3 days before organ procurement, the organ donor received a blood transfusion from a donor who had received a yellow fever vaccine 6 days before blood donation. INTERPRETATION: This investigation substantiates the use of metagenomic next-generation sequencing for the broad-based detection of rare or unexpected pathogens. Health-care workers providing vaccinations should inform patients of the need to defer blood donation for at least 2 weeks after receiving a yellow fever vaccine. Despite mitigation strategies and safety interventions, a low risk of transfusion-transmitted infections remains. FUNDING: US Centers for Disease Control and Prevention (CDC), the Biomedical Advanced Research and Development Authority, and the CDC Epidemiology and Laboratory Capacity Cooperative Agreement for Infectious Diseases.


Assuntos
Encefalite , Transplante de Órgãos , Vacina contra Febre Amarela , Humanos , Transfusão de Sangue , Encefalite/induzido quimicamente , Transplante de Órgãos/efeitos adversos , Estados Unidos/epidemiologia , Vírus da Febre Amarela/genética
9.
mBio ; 14(5): e0070623, 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37607061

RESUMO

IMPORTANCE: All enveloped viruses enter cells by fusing their envelope with a target cell membrane while avoiding premature fusion with membranes of the producer cell-the latter being particularly important for viruses that bud at internal membranes. Flaviviruses bud in the endoplasmic reticulum, are transported through the TGN to reach the external milieu, and enter other cells via receptor-mediated endocytosis. The trigger for membrane fusion is the acidic environment of early endosomes, which has a similar pH to the TGN of the producer cell. The viral particles therefore become activated to react to mildly acidic pH only after their release into the neutral pH extracellular environment. Our study shows that for yellow fever virus (YFV), the mechanism of activation involves actively knocking out the fusion brake (protein pr) through a localized conformational change of the envelope protein upon exposure to the neutral pH external environment. Our study has important implications for understanding the molecular mechanism of flavivirus fusion activation in general and points to an alternative way of interfering with this process as an antiviral treatment.


Assuntos
Flavivirus , Febre Amarela , Humanos , Flavivirus/genética , Proteínas do Envelope Viral/metabolismo , Vírus da Febre Amarela/genética , Membrana Celular/metabolismo
10.
Viruses ; 15(7)2023 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-37515107

RESUMO

As obligate intracellular parasites, viruses rely heavily on host cells for replication, and therefore dysregulate several cellular processes for their benefit. In return, host cells activate multiple signaling pathways to limit viral replication and eradicate viruses. The present study explores the complex interplay between viruses and host cells through next generation RNA sequencing as well as mass spectrometry (SILAC). Both the coding transcriptome and the proteome of human brain-derived U87 cells infected with Kunjin virus, Zika virus, or Yellow Fever virus were compared to the transcriptome and the proteome of mock-infected cells. Changes in the abundance of several hundred mRNAs and proteins were found in each infection. Moreover, the alternative splicing of hundreds of mRNAs was found to be modulated upon viral infection. Interestingly, a significant disconnect between the changes in the transcriptome and those in the proteome of infected cells was observed. These findings provide a global view of the coding transcriptome and the proteome of Flavivirus-infected cells, leading to a better comprehension of Flavivirus-host interactions.


Assuntos
Flavivirus , Vírus do Nilo Ocidental , Febre Amarela , Infecção por Zika virus , Zika virus , Humanos , Zika virus/genética , Zika virus/metabolismo , Vírus do Nilo Ocidental/genética , Vírus da Febre Amarela/genética , Vírus da Febre Amarela/metabolismo , Proteoma/genética , Transcriptoma , Flavivirus/genética , Replicação Viral , Encéfalo/metabolismo
11.
PLoS Negl Trop Dis ; 17(6): e0011407, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37276217

RESUMO

Beginning December 2016, sylvatic yellow fever (YF) outbreaks spread into southeastern Brazil, and Minas Gerais state experienced two sylvatic YF waves (2017 and 2018). Following these massive YF waves, we screened 187 free-living non-human primate (NHPs) carcasses collected throughout the state between January 2019 and June 2021 for YF virus (YFV) using RTqPCR. One sample belonging to a Callithrix, collected in June 2020, was positive for YFV. The viral strain belonged to the same lineage associated with 2017-2018 outbreaks, showing the continued enzootic circulation of YFV in the state. Next, using data from 781 NHPs carcasses collected in 2017-18, we used generalized additive mixed models (GAMMs) to identify the spatiotemporal and host-level drivers of YFV infection and intensity (an estimation of genomic viral load in the liver of infected NHP). Our GAMMs explained 65% and 68% of variation in virus infection and intensity, respectively, and uncovered strong temporal and spatial patterns for YFV infection and intensity. NHP infection was higher in the eastern part of Minas Gerais state, where 2017-2018 outbreaks affecting humans and NHPs were concentrated. The odds of YFV infection were significantly lower in NHPs from urban areas than from urban-rural or rural areas, while infection intensity was significantly lower in NHPs from urban areas or the urban-rural interface relative to rural areas. Both YFV infection and intensity were higher during the warm/rainy season compared to the cold/dry season. The higher YFV intensity in NHPs in warm/rainy periods could be a result of higher exposure to vectors and/or higher virus titers in vectors during this time resulting in the delivery of a higher virus dose and higher viral replication levels within NHPs. Further studies are needed to better test this hypothesis and further compare the dynamics of YFV enzootic cycles between different seasons.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Animais , Humanos , Vírus da Febre Amarela/genética , Brasil/epidemiologia , Surtos de Doenças , Callithrix
12.
PLoS One ; 18(5): e0284823, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37163522

RESUMO

Tick-borne encephalitis virus (TBEV) is one of the most threatening pathogens which affects the human central nervous system (CNS). TBEV circulates widely in Northern Eurasia. According to ECDC, the number of TBE cases increase annually. There is no specific treatment for the TBEV infection, thus vaccination is the main preventive measure. Despite the existence of several inactivated vaccines currently being licensed, the development of new TBEV vaccines remains a leading priority in countries endemic to this pathogen. Here we report new recombinant virus made by infectious subgenomic amplicon (ISA) approach using TBEV and yellow fever virus vaccine strain (YF17DD-UN) as a genetic backbone. The recombinant virus is capable of effective replication in mammalian cells and induce TBEV-neutralizing antibodies in mice. Unlike the original vector based on the yellow fever vaccine strain, chimeric virus became neuroinvasive in doses of 107-106 PFU and can be used as a model of flavivirus neuroinvasiveness, neurotropism and neurovirulence. These properties of hybrid structures are the main factors limiting their practical use as vaccines platforms.


Assuntos
Vírus da Encefalite Transmitidos por Carrapatos , Encefalite Transmitida por Carrapatos , Vacinas Virais , Vacina contra Febre Amarela , Humanos , Animais , Camundongos , Vacina contra Febre Amarela/genética , Vírus da Febre Amarela/genética , Mamíferos
13.
Viruses ; 15(3)2023 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-36992466

RESUMO

In recent decades, waves of yellow fever virus (YFV) from the Amazon Rainforest have spread and caused outbreaks in other regions of Brazil, including the Cerrado, a savannah-like biome through which YFV usually moves before arriving at the Atlantic Forest. To identify the vectors involved in the maintenance of the virus in semiarid environments, an entomological survey was conducted after confirmation of yellow fever (YF) epizootics at the peak of the dry season in the Cerrado areas of the state of Minas Gerais. In total, 917 mosquitoes from 13 taxa were collected and tested for the presence of YFV. Interestingly, mosquitoes of the Sabethes genus represented 95% of the diurnal captured specimens, displaying a peak of biting activity never previously recorded, between 4:30 and 5:30 p.m. Molecular analysis identified three YFV-positive pools, two from Sabethes chloropterus-from which near-complete genomes were generated-and one from Sa. albiprivus, whose low viral load prevented sequencing. Sa. chloropterus was considered the primary vector due to the high number of copies of YFV RNA and the high relative abundance detected. Its bionomic characteristics allow its survival in dry places and dry time periods. For the first time in Brazil, Sa. albiprivus was found to be naturally infected with YFV and may have played a role as a secondary vector. Despite its high relative abundance, fewer copies of viral RNA were found, as well as a lower Minimum Infection Rate (MIR). Genomic and phylogeographic analysis showed that the virus clustered in the sub-lineage YFVPA-MG, which circulated in Pará in 2017 and then spread into other regions of the country. The results reported here contribute to the understanding of the epidemiology and mechanisms of YFV dispersion and maintenance, especially in adverse weather conditions. The intense viral circulation, even outside the seasonal period, increases the importance of surveillance and YFV vaccination to protect human populations in affected areas.


Assuntos
Culicidae , Vírus da Febre Amarela , Humanos , Animais , Vírus da Febre Amarela/genética , Estações do Ano , Brasil/epidemiologia , Mosquitos Vetores
14.
J Virol Methods ; 316: 114717, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36972832

RESUMO

Yellow fever disease is a viral zoonosis that may result in a severe hemorrhagic disease. A safe and effective vaccine used in mass immunization campaigns has allowed control and mitigation against explosive outbreaks in endemic areas. Since the 1960's, re-emergent of the yellow fever virus has been observed. The timely implementation of control measures, to avoid or contain an ongoing outbreak requires rapid specific viral detection methods. Here a novel molecular assay, expected to detect all known yellow fever virus strains, is described. The method has demonstrated high sensitivity and specificity in real-time RT-PCR as well as in an endpoint RT-PCR set-up. Sequence alignment and phylogenetic analysis reveal that the amplicon resulting from the novel method covers a genomic region whose mutational profile is completely associated to the yellow fever viral lineages. Therefore, sequencing analysis of this amplicon allows for assignment of the viral lineage.


Assuntos
Vacina contra Febre Amarela , Febre Amarela , Humanos , Vírus da Febre Amarela/genética , Febre Amarela/diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Filogenia
15.
Viruses ; 15(2)2023 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-36851651

RESUMO

In Brazil, a yellow fever (YF) outbreak was reported in areas considered YF-free for decades. The low vaccination coverage and the increasing forest fragmentation, with the wide distribution of vector mosquitoes, have been related to yellow fever virus (YFV) transmission beyond endemic areas since 2016. Aiming to elucidate the molecular and phylogenetic aspects of YFV spread on a local scale, we generated 43 new YFV genomes sampled from humans, non-human primates (NHP), and primarily, mosquitoes from highly heterogenic areas in 15 localities from Rio de Janeiro (RJ) state during the YFV 2016-2019 outbreak in southeast Brazil. Our analysis revealed that the genetic diversity and spatial distribution of the sylvatic transmission of YFV in RJ originated from at least two introductions and followed two chains of dissemination, here named the YFV RJ-I and YFV RJ-II clades. They moved with similar dispersal speeds from the north to the south of the RJ state in parallel directions, separated by the Serra do Mar Mountain chain, with YFV RJ-I invading the north coast of São Paulo state. The YFV RJ-I clade showed a more significant heterogeneity across the entire polyprotein. The YFV RJ-II clade, with only two amino acid polymorphisms, mapped at NS1 (I1086V), present only in mosquitoes at the same locality and NS4A (I2176V), shared by all YFV clade RJ-II, suggests a recent clustering of YFV isolates collected from different hosts. Our analyses strengthen the role of surveillance, genomic analyses of YVF isolated from other hosts, and environmental studies into the strategies to forecast, control, and prevent yellow fever outbreaks.


Assuntos
Culicidae , Febre Amarela , Animais , Vírus da Febre Amarela/genética , Febre Amarela/epidemiologia , Brasil/epidemiologia , Filogenia , Mosquitos Vetores , Florestas
16.
Infect Dis Now ; 53(3): 104654, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36709865

RESUMO

INTRODUCTION: Unvaccinated individuals in endemic areas with proven enzootic transmission of Yellow fever virus are at risk of infection due to a dramatic shift in the epidemiology of the disease over recent years. For this reason, epidemiological surveillance and laboratory confirmation of cases have become mandatory. OBJECTIVE: To develop and test a control RNA for YFV detection through real-time RT-PCR. METHODS: A 437-bp insert containing the T7 promoter and the target sequences for two different in-house protocols was designed in the context of the pUC57 vector and obtained through gene synthesis. After T7-driven in vitro transcription, standard curves were developed for Log10 serial dilutions of the YFV control RNA with 8 replicates. RESULTS: A dynamic range of quantification of 10 orders of magnitude was observed with a limit of detection of 6.3 GCE/µL (95% CI, 2.6 to 139.4 GCE/µL). CONCLUSION: The plasmid construct is available for YFV molecular test validation on clinical, entomological, and epizootic samples.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Humanos , Vírus da Febre Amarela/genética , Febre Amarela/diagnóstico , Febre Amarela/epidemiologia , Transcrição Reversa , Reação em Cadeia da Polimerase Via Transcriptase Reversa , RNA
17.
J Virol Methods ; 311: 114638, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36328081

RESUMO

The genus Flavivirus in the Flaviridae contains arthropod born viruses associated with high public health burdens like Zika, Dengue or Yellow fever. Saboya virus (SABV) is an understudied flavivirus grouping in the same genetic sub-group as Yellow Fever Virus (YFV) together with Sepik virus (SEPV) and Wesselbron virus (WSLV). Flavivirus infections are characterized by non-specific clinical presentations resulting in a high risk of misdiagnosis. SABV virus has been shown to circulate in the Sahelian zone and in central Africa. To study this virus we a qRT-PCR system based on TaqMan chemistry was developed to allow rapid and specific detection of SABV. The SABV assay was evaluated on available SABV isolates and others flaviviruses (DENV, ZIKV, YFV, WNV, KEDV). The system reliably detected all used SABV strains without cross amplification of other flaviviruses. In term of sensitivity the SABV assay detect up to 40.25 copies of SABV standard DNA molecule per ul. This system can be easily added to the available panel of arboviruses detection assays as a reliable tool to study virus prevalence in human, vertebrate and insect-vector samples.


Assuntos
Vírus da Dengue , Flavivirus , Febre Amarela , Infecção por Zika virus , Zika virus , Humanos , Flavivirus/genética , Febre Amarela/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real , Vírus da Febre Amarela/genética
18.
Viruses ; 16(1)2023 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-38257732

RESUMO

Yellow fever virus (YFV) is the agent of yellow fever (YF), which affects both humans and non-human primates (NHP). Neotropical NHP are highly susceptible to YFV and considered sentinels for YFV circulation. Brazil faced a significant YF outbreak in 2017-2018, with over 2000 human cases and 2000 epizootics cases, mainly in the State of Minas Gerais, Brazil. This study aimed to investigate whether YFV circulation persisted in NHP after the human outbreak had subsided. To this end, NHP carcass samples collected in Minas Gerais from 2021 to 2023 were screened for YFV. RNA was extracted from tissue fragments and used in RT-qPCR targeting the YFV 5'UTR. Liver and lung samples from 166 animals were tested, and the detection of the ß-actin mRNA was used to ensure adequacy of RNA isolation. YFV RNA was detected in the liver of 18 NHP carcasses collected mainly from urban areas in 2021 and 2022. YFV positive NHP were mostly represented by Callithrix, from 5 out of the 12 grouped municipalities (mesoregions) in Minas Gerais state. These findings reveal the continued YFV circulation in NHP in urban areas of Minas Gerais during 2021 and 2022, with the attendant risk of re-establishing the urban YFV cycle.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Animais , Vírus da Febre Amarela/genética , Brasil/epidemiologia , Febre Amarela/epidemiologia , Febre Amarela/veterinária , Regiões 5' não Traduzidas , Callithrix
19.
Mem Inst Oswaldo Cruz ; 117: e220127, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36478156

RESUMO

BACKGROUND: In Brazil, the yellow fever virus (YFV) is maintained in a sylvatic cycle involving wild mosquitoes and non-human primates (NHPs). The virus is endemic to the Amazon region; however, waves of epidemic expansion reaching other Brazilian states sporadically occur, eventually causing spillovers to humans. OBJECTIVES: To report a surveillance effort that led to the first confirmation of YFV in NHPs in the state of Minas Gerais (MG), Southeast region, in 2021. METHODS: A surveillance network was created, encompassing the technology of smartphone applications and coordinated actions of several research institutions and health services to monitor and investigate NHP epizootics. FINDINGS: When alerts were spread through the network, samples from NHPs were collected and YFV infection confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and genome sequencing at an interval of only 10 days. Near-complete genomes were generated using the Nanopore MinION sequencer. Phylogenetic analysis indicated that viral genomes were related to the South American genotype I, clustering with a genome detected in the Amazon region (state of Pará) in 2017, named YFVPA/MG sub-lineage. Fast YFV confirmation potentialised vaccination campaigns. MAIN CONCLUSIONS: A new YFV introduction was detected in MG 6 years after the beginning of the major outbreak reported in the state (2015-2018). The YFV strain was not related to the sub-lineages previously reported in MG. No human cases have been reported, suggesting the importance of coordinated surveillance of NHPs using available technologies and supporting laboratories to ensure a quick response and implementation of contingency measures to avoid YFV spillover to humans.


Assuntos
Vírus da Febre Amarela , Vírus da Febre Amarela/genética , Filogenia , Brasil/epidemiologia
20.
PLoS One ; 17(12): e0278982, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36508435

RESUMO

Yellow fever virus (YFV) is the agent of the most severe mosquito-borne disease in the tropics. Recently, Brazil suffered major YFV outbreaks with a high fatality rate affecting areas where the virus has not been reported for decades, consisting of urban areas where a large number of unvaccinated people live. We developed a machine learning framework combining three different algorithms (XGBoost, random forest and regularized logistic regression) to analyze YFV genomic sequences. This method was applied to 56 YFV sequences from human infections and 27 from non-human primate (NHPs) infections to investigate the presence of genetic signatures possibly related to disease severity (in human related sequences) and differences in PCR cycle threshold (Ct) values (in NHP related sequences). Our analyses reveal four non-synonymous single nucleotide variations (SNVs) on sequences from human infections, in proteins NS3 (E614D), NS4a (I69V), NS5 (R727G, V643A) and six non-synonymous SNVs on NHP sequences, in proteins E (L385F), NS1 (A171V), NS3 (I184V) and NS5 (N11S, I374V, E641D). We performed comparative protein structural analysis on these SNVs, describing possible impacts on protein function. Despite the fact that the dataset is limited in size and that this study does not consider virus-host interactions, our work highlights the use of machine learning as a versatile and fast initial approach to genomic data exploration.


Assuntos
Febre Amarela , Vírus da Febre Amarela , Animais , Humanos , Vírus da Febre Amarela/genética , Febre Amarela/epidemiologia , Brasil/epidemiologia , Primatas , Aprendizado de Máquina , Nucleotídeos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...