Publications by authors named "Rafael Freitas Oliveira Franca"

We generated 238 Zika virus (ZIKV) genomes from 135 persons in Brazil who had samples collected over 1 year to evaluate virus persistence. Phylogenetic inference clustered the genomes together with previously reported ZIKV strains from northern Brazil, showing that ZIKV has been remained relatively stable over time. Temporal phylogenetic analysis revealed limited within-host diversity among most ZIKV-persistent infected associated samples.

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Rhythmic regulations are virtually described in all physiological processes, including central nervous system development and immunologic responses. Zika virus (ZIKV), a neurotropic arbovirus, has been recently linked to a series of birth defects and neurodevelopmental disorders. Given the well-characterized role of the intrinsic cellular circadian clock within neurogenesis, cellular metabolism, migration, and differentiation among other processes, this study aimed to characterize the influence of ZIKV infection in the circadian clock expression in human neuronal cells.

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Article Synopsis
  • * A total of 260 individuals were monitored for 12 months, revealing that Zika virus RNA was detectable for long periods, especially in semen, and various factors influenced how quickly the virus cleared from different fluids.
  • * The research highlighted the potential for recurrent detection of Zika virus even after it was cleared, underscoring the importance of ongoing monitoring and prevention strategies to manage its transmission.
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Chikungunya virus (CHIKV) is an arthropod-borne virus recently associated with large outbreaks in many parts of the world. Infection is typically manifested as a febrile and self-limited illness, characterized by joint pain and myalgia, albeit severe neurological manifestations are also reported. Although CHIKV is not recognized as a truly neurotropic virus, neurons, astrocytes, and oligodendrocytes are susceptible to infection .

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Newcastle disease virus (NDV), also known as avian paramyxoviruses 1 (APMV-1) is among the most important viruses infecting avian species. Given its widespread circulation, there is a high risk for the reintroduction of virulent strains into the domestic poultry industry, making the surveillance of wild and domestic birds a crucial process to appropriately respond to novel outbreaks. In the present study, we investigated an outbreak characterized by the identification of sick pigeons in a large municipality in Northeastern Brazil in 2018.

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Background: Zika virus infection is commonly described as a mild and self-limiting illness. However, cardiac complications were associated with acute Zika virus infection.

Case Presentation: A 46-year-old woman without previous comorbidities with a 1-day history of symptoms tested positive for ZIKV by real time reverse transcriptase polymerase chain reaction (rRT-PCR).

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Global health research partnerships with institutions from high-income countries and low- and middle-income countries are one of the European Commission's flagship programmes. Here, we report on the ZikaPLAN research consortium funded by the European Commission with the primary goal of addressing the urgent knowledge gaps related to the Zika epidemic and the secondary goal of building up research capacity and establishing a Latin American-European research network for emerging vector-borne diseases. Five years of collaborative research effort have led to a better understanding of the full clinical spectrum of congenital Zika syndrome in children and the neurological complications of Zika virus infections in adults and helped explore the origins and trajectory of Zika virus transmission.

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Article Synopsis
  • After a decline in Zika and dengue cases in Brazil between 2017-2018, dengue resurged dramatically in 2019 with approximately 2.1 million reported cases.
  • The study analyzes epidemiological, climatological, and genomic data to understand the dynamics of dengue in Brazil, highlighting low transmission rates despite suitable conditions in 2017-2018.
  • Researchers found that the local dengue virus lineages responsible for outbreaks in 2018-2019 had been circulating quietly for several years, suggesting that dengue could remain at low levels before causing significant outbreaks when conditions improve.
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Background: The Zika virus outbreak has triggered a set of local and global actions for a rapid, effective, and timely public health response. A World Health Organization (WHO) initiative, supported by the Department of Chronic Condition Diseases and Sexually Transmitted Infections (DCCI) of the Health Surveillance Secretariat (SVS), Brazil Ministry of Health (MoH) and other public health funders, resulted in the start of the "Study on the persistence of Zika virus in body fluids of patients with ZIKV infection in Brazil - ZIKABRA study". The ZIKABRA study was designed to increase understanding of how long ZIKV persists in bodily fluids and informing best measures to prevent its transmission.

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We evaluated sweat, blood and urine specimens obtained from an ongoing cohort study in Brazil. Samples were collected at pre-established intervals after the initial rash presentation and tested for Zika virus (ZIKV) RNA presence by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). From 254 participants with confirmed infection, ZIKV RNA was detected in the sweat of 46 individuals (18.

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Objective: To determine the clinical phenotype of Guillain-Barré syndrome (GBS) after Zika virus (ZIKV) infection, the anti-glycolipid antibody signature, and the role of other circulating arthropod-borne viruses, we describe a cohort of GBS patients identified during ZIKV and chikungunya virus (CHIKV) outbreaks in Northeast Brazil.

Methods: We prospectively recruited GBS patients from a regional neurology center in Northeast Brazil between December 2014 and February 2017. Serum and CSF were tested for ZIKV, CHIKV, and dengue virus (DENV), by RT-PCR and antibodies, and serum was tested for GBS-associated antibodies to glycolipids.

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Background: Since 2015, the arthropod-borne viruses (arboviruses) Zika and chikungunya have spread across the Americas causing outbreaks, accompanied by increases in immune-mediated and infectious neurological disease. The spectrum of neurological manifestations linked to these viruses, and the importance of dual infection, are not known fully. We aimed to investigate whether neurological presentations differed according to the infecting arbovirus, and whether patients with dual infection had a different disease spectrum or severity.

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Article Synopsis
  • * In 2014, CHIKV was introduced to Brazil through two different genotypes: the Asian/Caribbean and the African ECSA, causing outbreaks among unexposed populations.
  • * Recent genomic sequencing from a Northeast Brazil outbreak showed that both genotypes are now circulating together, indicating coinfection may be common in these areas, requiring better understanding of CHIKV's spread.
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We detected Zika virus RNA in rectal swab samples from 10 patients by using real-time reverse transcription PCR, and we isolated the virus from 1 patient. The longest interval from symptom onset to detection was 14 days. These findings are applicable to diagnosis and infection prevention recommendations.

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Article Synopsis
  • Zika virus (ZIKV) has been detected in various body fluids of infected individuals, where it may linger longer in urine and semen, raising concerns about its transmission and potential severe health effects like microcephaly and Guillain-Barré syndrome.
  • This study will recruit non-pregnant adults aged 18+ with confirmed ZIKV infection to analyze the presence of the virus in different biological specimens over a 12-month period, using methods like RT-PCR and assessing for other co-infections.
  • The research aims to explore ZIKV’s persistence and reactivation in the body, providing crucial insights that could inform prevention strategies and enhance understanding of the virus’s behavior in the long term.*
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Since the emergence of Zika virus (ZIKV) in Brazil in 2015, 48 countries and territories in the Americas have confirmed autochthonous cases of disease caused by the virus. ZIKV-associated neurological manifestations and congenital defects make the development of safe and effective antivirals against ZIKV of utmost importance. Here we evaluated the antiviral activity of 6-methylmercaptopurine riboside (6MMPr), a thiopurine nucleoside analogue derived from the prodrug azathioprine, against the epidemic ZIKV strain circulating in Brazil.

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Background: Prophylactic treatment regimens to prevent mother-to-child HIV transmission include protease inhibitors Lopinavir and Ritonavir. Lopinavir and Ritonavir have been reported to be able to induce intracellular oxidative stress in diverse cellular models, however scarce informations are available about protease inhibitor effects of in the central nervous system (CNS). In our study we evaluated the impact of protease inhibitors on a cell neuronal model.

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Dengue is the most important arbovirus disease throughout the world and it is responsible for more than 500,000 dengue hemorrhagic cases and 22,000 deaths every year. One vaccine was recently licensed for human use in Brazil, Mexico and Philippines and although at least seven candidates have been in clinical trials the results of the most developed CYD vaccine have demonstrated immunization problems, such as uneven protection and interference between serotypes. We constructed a vaccine candidate based on vesicular stomatitis virus (VSV) expression of pre-membrane (prM) and envelope (E) proteins of dengue-2 virus (DENV-2) and tested it in mice to evaluate immunogenicity and protection against DENV-2 infection.

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Rocio virus (ROCV) is a flavivirus, probably transmitted by Culex mosquitoes and maintained in nature as a zoonosis of wild birds. Rocio virus caused a human epidemic of severe encephalitis that lasted from 1973 to 1980 in the Ribeira valley, in the southeastern coast of Brazil. After this outbreak, serologic evidence of ROCV circulation has been reported and public health authorities are concerned about a return of ROCV outbreaks in Brazil.

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In an effort to develop a suitable DNA vaccine candidate for dengue, using dengue-3 virus (DENV-3) as a prototype, the genes coding for premembrane (prM) and envelope proteins (E) were inserted into an expression plasmid. After selecting recombinant clones containing prM/E genes, protein expression in the cell monolayer was detected by indirect immunofluorescence and immunoprecipitation assays. After selecting three vaccine candidates (pVAC1DEN3, pVAC2DEN3 and pVAC3DEN3), they were analyzed in vivo to determine their ability to induce a DENV-3-specific immune response.

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