Biology subjects

da Silva, A. F.

Publications and source records attributed to da Silva, A. F..

5 recordsLinked to original sources

bioRxiv2025

Ambecovirus, a novel Betacoronavirus subgenus circulating in neotropical bats sheds new light on bat-borne coronaviruses evolution

Understanding the viral diversity harboured by wildlife is essential for effective prediction and prevention of future zoonotic outbreaks. Bats, in particular, are recognized as natural reservoirs for several zoonotic viral pathogens of high impact on public health, including coronaviruses responsible for SARS, the rabies virus, Marburg, Ebola, Nipah and Hendra viruses. However, the large extent of bat viruses remains unexplored, especially in highly biodiverse regions of the Neotropics such as Brazil. We used a meta-transcriptomic to characterize new virus genomes found in blood, oral and anal samples collected from cave- and non-cave bats from Northeast Brazil. 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-/Nebecovirus 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 could not be identified due to high dissimilarity relative to known congeneres. The detection of Ambercovirus in sympatric Pteronotus gymnonotus and Carollia perspicillata bats suggests 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.

evolutionary biology↗

bioRxiv2024

Detection of Deltacoronavirus in Environmental Fecal Samples from Seabirds in the Saint Peter and Saint Paul Archipelago, central equatorial Atlantic Ocean

This study investigates the presence of avian coronaviruses (CoVs), influenza A viruses (IAVs), and Avian rotaviruses (RVs) group A in seabird populations inhabiting the Saint Peter and Saint Paul Archipelago (SPSPA), an isolated and remote oceanic island situated in the equatorial region of the Atlantic Ocean. In July 2022, 95 environmental fecal samples were collected from seabird colonies and screened for the viruses by quantitative one-step real-time RT-PCR (IAVs and RVs), by the conventional pancoronavirus RT-PCR protocols and metatranscriptomics of a positive sample. Four environmental feces samples tested positive for CoVs. Avian IAVs and RVs were not detected. Phylogenetic analysis revealed CoVs closely related to avian deltacoronaviruses previously identified in waterbirds from Asia and Australia. We could not recover the CoV by metatranscriptomics but we recovered a single viral contig of an avian enterovirus. The findings contribute valuable insights into virus dynamics among seabird populations, laying the groundwork for future investigations in this field.

molecular biology↗

bioRxiv2024

Genomic and phenotypic characterization of an Oropouche virus strain implicated in the 2023-24 large-scale outbreak in Brazil

The Orthobunyavirus oropoucheense in a arthropod borne zoonotic pathogen known to infect sylvatic animals and humans by means of biting midges transmission. Several large-scale human outbreaks of Oropouche virus (OROV), primarily confined to the Amazon region, were documented over the decades. However, since 2022, more widespread OROV outbreaks have been unfolding in Brazil and across South America, with cases exported to Cuba, Italy, and Germany. I In Brazil, the virus has reached and established communitary transmission in states from all major regions of the country. Here we isolated, characterized the cytopathic effect and the full genomic sequence of two OROV isolates from the current outbreak. Our data shows that OROV can readily infect and replicate in non-human primate cells, supporting the role of non-human primates as important reservoirs. Phylogenetic data supports a direct introduction of the same lineages causing the 2022-24 outbreak in Brazil from the Amazonas state, the epicenter of the epidemics in Brazil. Lastly, as case counts accumulate in the state and the Northeast region, clear evidence supports established and sustained transmission. Continued studies are critical to understand the transmission cycle in this region, the most important vectors and reservoirs, to appropriately deploy control measures.

microbiology↗

bioRxiv2023

RNA virome of sylvatic mosquitoes from northeast Brazil reveals a divergent and diverse insect-specific viral community

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 (ISV) 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 brazilian biomes. Here, we characterized the RNA virome of 10 sylvatic mosquitos 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 RdRp amino acid divergence from other known viruses suggests that the viruses characterized here represent at least 34 new viral species. Therefore, the sylvatic mosquitoes viral community is majorly 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. These findings will help to understand the interactions and coevolution between mosquitoes and viruses in nature. ImportanceMosquitoes 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 ISVs. In this study, we characterized the RNA virome of sylvatic mosquitoes from Northeast Brazil using unbiased metatranscriptomic sequencing and in depth bioinformatics 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. Lastly, it also provided several complete genomes that warrants further assessment for mosquito and vertebrate host pathogenicity and their potential interference with pathogenic arboviruses.

genomics↗

bioRxiv2019

Time and mode of Culicidae evolutionary history

Mosquitoes are insects of medical importance due their role as vectors of different pathogens to humans and other mammals. There is a lack of information about the evolutionary history and phylogenetic positioning of the majority of mosquitoes species. Here we sequenced the mitogenomes of mosquitoes species through low-coverage sequencing and data mining. A total of 37 draft mitogenomes were assembled representing 11 genera and 16 of those were sequenced for the first time. The recovered mitogenomes showed a coverage breadth average of 81.24%. Most of the species were clustered in monophyletic clades with other members of their own genus with exception of the Aedini tribe which was paraphyletic corroborating other findings. We established for the first time the monophyletic status of eight species from the tribe Mansoniini including both Coquillettidia and Mansonia genus and established the basal positioning of Aedeomyiini and Uranotaeniini tribes regarding the Culicinae subfamily. Molecular clock dated the Culicidae family emergence around 273 MYA and the split between Anophelinae and Culicinae subfamily around 182 MYA in the Jurassic period. Low-coverage sequencing is effective to recover mitogenomes, establish phylogenetic knowledge generating basic fundamental information to the understanding of the role of these species as pathogen vectors.

evolutionary biology↗