Alexandre Freitas da Silva

Ms. Alexandre Freitas da Silva

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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 December 2020 in Viruses
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MPMarcelo Henrique Santos Paiva
Marcelo Henrique Santos Paiva
DGDuschinka Ribeiro Duarte Guedes
Duschinka Ribeiro Duarte Guedes
CDCássia Docena
Cássia Docena
MBMatheus BEZERRA
Matheus BEZERRA
FDFilipe Dezoeei
Filipe Dezoeei
GWGabriel Luz Wallau
Gabriel Luz Wallau
Multiple epicenters of the SARS-CoV-2 pandemic have emerged since the first pneumonia cases in Wuhan, China, such as Italy, USA, and Brazil. Brazil is the third-most affected country worldwide, but genomic sequences of SARS-CoV-2 strains are mostly restricted to states from the Southeast region. Pernambuco state, located in the Northeast region, is the sixth most affected Brazilian state, but very few genomic sequences from the strains circulating in this region are available. We sequenced 101 strains of SARS-CoV-2 from patients presenting Covid-19 symptoms that reside in Pernambuco. Phylogenetic reconstructions revealed that all genomes belong to the B lineage and most of the samples (88%) were classified as lineage B.1.1. We detected multiple viral introductions from abroad (likely from Europe) as well as six local B.1.1 clades composed by Pernambuco only strains. Local clades comprise sequences from the capital city (Recife) and other country-side cities, corroborating the community spread between different municipalities of the state. These findings demonstrate that different from Southeastern Brazilian states where the epidemics were majorly driven by one dominant lineage (B.1.1.28 or B.1.1.33), the early epidemic phase at the Pernambuco state was driven by multiple B.1.1 lineages seeded through both national and international traveling.

28 February 2024 in Nature Communications
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TGTiago Gräf
Tiago Gräf
ACAlexander Augusto Martinez Caballero
Alexander Augusto Martinez Caballero
GBGonzalo Bello
Gonzalo Bello
SDSimon Dellicour
Simon Dellicour
PLPhilippe Lemey
Philippe Lemey
JLJuliana Leite
Juliana Leite
Latin America and Caribbean (LAC) regions were an important epicenter of the COVID-19 pandemic and SARS-CoV-2 evolution. Through the COVID-19 Genomic Surveillance Regional Network (COVIGEN), LAC countries produced an important number of genomic sequencing data that made possible an enhanced SARS-CoV-2 genomic surveillance capacity in the Americas, paving the way for characterization of emerging variants and helping to guide the public health response. In this study we analyzed approximately 300,000 SARS-CoV-2 sequences generated between February 2020 and March 2022 by multiple genomic surveillance efforts in LAC and reconstructed the diffusion patterns of the main variants of concern (VOCs) and of interest (VOIs) possibly originated in the Region. Our phylogenetic analysis revealed that the spread of variants Gamma, Lambda and Mu reflects human mobility patterns due to variations of international air passenger transportation and gradual lifting of social distance measures previously implemented in countries. Our results highlight the potential of genetic data to reconstruct viral spread and unveil preferential routes of viral migrations that are shaped by human mobility patterns.

20 August 2024 in Journal of Virology
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Journal Article
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ASAlexandre Freitas da Silva
Alexandre Freitas da Silva
LMLaís Ceschini Machado
Laís Ceschini Machado
LSLuisa Maria Inácio da Silva
Luisa Maria Inácio da Silva
FDFilipe Zimmer Dezordi
Filipe Zimmer Dezordi
GWGabriel Luz Wallau
Gabriel Luz Wallau
Mosquitoes can transmit several pathogenic viruses to humans, but their natural viral community is also composed of a myriad of other viruses such as insect-specific viruses (ISVs) and those that infect symbiotic microorganisms. Besides a growing number of studies investigating the mosquito virome, the majority are focused on few urban species, and relatively little is known about the virome of sylvatic mosquitoes, particularly in high biodiverse biomes such as the Brazilian biomes. Here, we characterized the RNA virome of 10 sylvatic mosquito species from Atlantic forest remains at a sylvatic–urban interface in Northeast Brazil employing a metatranscriptomic approach. A total of 16 viral families were detected. The phylogenetic reconstructions of 14 viral families revealed that the majority of the sequences are putative ISVs. The phylogenetic positioning and, in most cases, the association with a high RNA-dependent RNA polymerase amino acid divergence from other known viruses suggests that the viruses characterized here represent at least 34 new viral species. Therefore, the sylvatic mosquito viral community is predominantly composed of highly divergent viruses highlighting the limited knowledge we still have about the natural virome of mosquitoes in general. Moreover, we found that none of the viruses recovered were shared between the species investigated, and only one showed high identity to a virus detected in a mosquito sampled in Peru, South America. These findings add further in-depth understanding about the interactions and coevolution between mosquitoes and viruses in natural environments. IMPORTANCE: Mosquitoes are medically important insects as they transmit pathogenic viruses to humans and animals during blood feeding. However, their natural microbiota is also composed of a diverse set of viruses that cause no harm to the insect and other hosts, such as insect-specific viruses. In this study, we characterized the RNA virome of sylvatic mosquitoes from Northeast Brazil using unbiased metatranscriptomic sequencing and in-depth bioinformatic approaches. Our analysis revealed that these mosquitoes species harbor a diverse set of highly divergent viruses, and the majority comprises new viral species. Our findings revealed many new virus lineages characterized for the first time broadening our understanding about the natural interaction between mosquitoes and viruses. Finally, it also provided several complete genomes that warrant further assessment for mosquito and vertebrate host pathogenicity and their potential interference with pathogenic arboviruses.

1 August 2021 in Virus Research
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Journal Article
Closed access
ASAlexandre Freitas da Silva
Alexandre Freitas da Silva
FDFilipe Dezoeei
Filipe Dezoeei
LMLaís Ceschini Machado
Laís Ceschini Machado
RCRodrigo Carvalho
Rodrigo Carvalho
SQSi Qin
Si Qin
GWGabriel Luz Wallau
Gabriel Luz Wallau

7 July 2018 in Mobile DNA
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Journal Article
Open access
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ASAlexandre Freitas da Silva
Alexandre Freitas da Silva
FDFilipe Dezoeei
Filipe Dezoeei
ELElgion L S Loreto
Elgion L S Loreto
GWGabriel Luz Wallau
Gabriel Luz Wallau
The majority of Eukaryotic genomes are composed of a small portion of stable (non-mobile) genes and a large fraction of parasitic mobile elements such as transposable elements and endogenous viruses: the Mobilome. Such important component of many genomes are normally underscored in genomic analysis and detailed characterized mobilomes only exists for model species. In this study, we used a combination of de novo and homology approaches to characterize the Mobilome of two non-model parasitoid wasp species. The different methodologies employed for TE characterization recovered TEs with different features as TE consensus number and size. Moreover, some TEs were detected only by one or few methodologies. RepeatExplorer and dnaPipeTE estimated a low TE content of 5.86 and 4.57% for Braconidae wasp and 5.22% and 7.42% for L. boulardi species, respectively. Both mobilomes are composed by a miscellaneous of ancient and recent elements. Braconidae wasps presented a large diversity of Maverick/Polintons Class II TEs while other TE superfamilies were more equally diverse in both species. Phylogenetic analysis of reconstructed elements showed that vertical transfer is the main mode of transmission. Different methodologies should be used complementarity in order to achieve better mobilome characterization. Both wasps genomes have one of the lower mobilome estimates among all Hymenoptera genomes studied so far and presented a higher proportion of Class II than Class I TEs. The large majority of superfamilies analyzed phylogenetically showed that the elements are being inherited by vertical transfer. Overall, we achieved a deep characterization of the mobilome in two non-model parasitoid wasps improving our understanding of their evolution.

9 January 2025 in Virus Evolution
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Journal Article
Open access
GWGabriel Luz Wallau
Gabriel Luz Wallau
EBEder Barbier
Eder Barbier
LMLais Ceschini Machado
Lais Ceschini Machado
ASAlexandre Freitas da Silva
Alexandre Freitas da Silva
YDYago Jose Mariz Dias
Yago Jose Mariz Dias
Daniel CadarDaniel Cadar
Daniel Cadar
Understanding the viral diversity harboured by wildlife is essential for effective mapping and prevention of future zoonotic outbreaks. Bats, in particular, are recognized as natural reservoirs for several high-impact zoonotic viral pathogens, including coronaviruses responsible for Severe Acute Respiratory Syndrome (SARS), the rabies virus, diverse paramyxoviruses, Marburg, Ebola, Nipah, and Hendra viruses. However, a large extent of bat viruses remains unexplored, especially in highly biodiverse regions of the Neotropics such as Brazilian ecosystems. We used a meta-transcriptomic approach to characterize new virus genomes found in blood, oral, and anal samples collected from cave- and noncave bats from Northeast Brazil, Caatinga, and Atlantic Forest biomes. From a total of 19 coronavirus-positive bats, we have assembled two complete genomes of a new Betacoronavirus subgenus, named Ambecovirus (American betacoronavirus). The subgenus herein described is phylogenetically placed between the Sarbeco-/Hibeco-/Nobecovirus and the Merbeco-/Embecovirus clades, being basal to the former. While the conserved S2 region of the spike protein retained hallmark domains, including HR1 and HR2, the S1/S2 cleavage site and the furin cleavage site, the S1 region consistently displayed only the N-terminal domain. The receptor-binding domain from the C-terminal domai (CTD) region could not be identified due to high dissimilarity relative to known congeners. The detection of Ambercovirus in sympatric Pteronotus gymnonotus and Carollia perspicillata bats suggests potential interspecies transmission. Longitudinal sampling confirmed persistent Ambecovirus infection in P. gymnonotus over multiple years and virus dispersion at a minimum distance of 270 km between caves. The present study confirms that viral diversity in neotropical hosts remains largely unknown, not just in Brazil but likely in the other countries of the region, supporting the need for a systematic approach to virome exploration and analysis followed by in vitro experimentation to assess zoonotic potential.