Gabriel Luz Wallau

Oswaldo Cruz Foundation | FIOCRUZ · Departamento de Entomologia (CPqAM)

Recombination plays a crucial role in the evolution of SARS-CoV-2. The Omicron XBB* recombinant lineages are a noteworthy example, as they have been the dominant SARS-CoV-2 variant worldwide in the first half of 2023. Since November 2023, a new recombinant lineage between Omicron subvariants XBB and BA.2.86, designated XDR, has been detected mainly...

Arbovirus surveillance of wild-caught mosquitoes is an affordable and sensitive means of monitoring virus transmission dynamics at various spatial-temporal scales, and emergence and re-emergence during epidemic and interepidemic periods. A variety of molecular diagnostics for arbovirus screening of mosquitoes (known as xeno-monitoring) are availabl...

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...

We present the genome sequence and organization and evidence of persistence of a new picorna-like virus infecting the flatworm Stenostomum leucops. The complete genome sequence belongs to a virus with a positive single-stranded RNA genome with two open reading frames (ORFs) flanked by untranslated regions and a polyadenylated C-terminus. The ORFs e...

Rabies virus (RABV), a fatal zoonotic pathogen, remains a significant public health concern, with bat-maintained lineages accounting for all currently documented cases in Brazil. Despite the availability of pharmacological prophylaxis for humans and animals, the high genetic diversity of RABV in diverse natural bat hosts and continued circulation i...

Wolbachia are endosymbiotic bacteria that infect a wide range of arthropods and filarial nematodes, often manipulating host reproduction. The efficacy of Wolbachia-based interventions for dengue and chikungunya control has been validated through numerous field studies in recent years. This study aimed to investigate the diversity and prevalence of...

The Orthobunyavirus oropoucheense species encompasses a group of arthropod-borne zoonotic viruses transmitted by biting midges to animals including humans. Several large-scale human outbreaks caused by the prototype member of this species , Oropouche virus (OROV) have been documented since the 1970s and were primarily confined to the Amazon basin....

Bird species are known to be the main reservoir of a range of respiratory viruses such as Influenza, Newcastle and Coronaviruses. Migratory birds are particularly important for the maintenance and long distance spread of the virus to wild bird and poultry species but eventually to mammal species as well. Antarctica’s pristine environment and wildli...

The surveillance and detection of zoonotic pathogens in animals is essential for predicting disease transmission pathways and the risks of spillover, but challenges include the costs, ethics and technical expertise required for vertebrate trapping, serum sampling and antibody or virus screening. Surveillance using haematophagous arthropods as a sam...

The design of proteins capable to effectively bind to specific protein targets is crucial for developing therapies, diagnostics, and vaccine candidates for viral infections. Here, we introduce a complementarity-determining regions (CDRs)-grafting approach for designing nanobodies (Nbs) that target specific epitopes, with the aid of computer simulat...

Horizontal gene transfer is a phenomenon of genetic material transmission between species with no parental relationship. It has been characterized among several major branches of life, including among prokaryotes, viruses and eukaryotes. The characterization of endogenous elements derived from viruses or bacteria provides a snapshot of past host-pa...

Objectives The SARS-CoV-2 JN.1 lineage emerged in late 2023 and quickly replaced the XBB lineages, becoming the predominant Omicron variant worldwide in 2024. We estimate the epidemiological impact of this SARS-CoV-2 lineage replacement in Brazil and we further assessed the cross-reactive neutralizing antibody (NAb) responses in a cohort of convale...

The Brazilian western Amazon is experiencing its largest laboratory-confirmed Oropouche virus (OROV) outbreak, with more than 6,300 reported cases between 2022 and 2024. In this study, we sequenced and analyzed 382 OROV genomes from human samples collected in Amazonas, Acre, Rondônia and Roraima states, between August 2022 and February 2024, to unc...

Dengue virus (DENV) is currently causing epidemics of unprecedented scope in endemic settings and expanding to new geographical areas. It is therefore critical to track this virus using genomic surveillance. However, the complex patterns of viral genomic diversity make it challenging to use the existing genotype classification system. Here, we prop...

Advances in high throughput genomic sequencing and bioinformatics have revolutionized our understanding of the biology of pathogenic organisms, including those transmitted by vectors. The use of these technologies has enabled precise identification and tracking of pathogens based on mutational profiles. Elucidating transmission dynamics and evoluti...

Western equine encephalitis virus (WEEV) is a mosquitoborne virus that reemerged in December 2023 in Argentina and Uruguay, causing a major outbreak. We investigated the outbreak using epidemiologic, entomological, and genomic analyses, focusing on WEEV circulation near the Argentina‒Uruguay border in Rio Grande do Sul state, Brazil. During Novembe...

Deadly outbreaks among poultry, wild birds, and carnivorous mammals by the highly pathogenic H5N1 virus of the clade 2.3.4.4b have been reported in South America. The increasing virus incidence in various mammal species poses a severe zoonotic and pandemic threat. In Uruguay, the clade 2.3.4.4b viruses were first detected in February 2023, affectin...

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 hav...

The Brazilian western Amazon region is currently experiencing its largest laboratory confirmed Oropouche virus (OROV) outbreak, with nearly 6,000 reported cases in the states of Amazonas (AM), Acre (AC), Rondonia (RO), and Roraima (RR), between August 2022 and March 2024. Here, we sequenced and analyzed 382 full-length OROV genomes from human sampl...

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...

The need for the identification of risk factors associated to COVID-19 disease severity remains urgent. Patients' care and resource allocation can be potentially different and are defined based on the current classification of disease severity. This classification is based on the analysis of clinical parameters and routine blood tests, which are no...

Mpox is a zoonotic viral disease caused by the monkeypox virus (MPXV). Human cases have been mainly restricted to the African continent until the worldwide multi-country outbreak unfolded in 2022. We reconstructed epidemiological links of MPXV infections using genomic epidemiology in Rio Grande do Sul State, southern Brazil, during 2022 and 2023. W...

The Western Equine Encephalitis Virus (WEEV) is transmitted between mosquitoes and wild birds. Mosquitoes can spread the virus to horses and human populations, causing severe encephalitis and death. The most recent large outbreak of WEEV occurred in the Southern cone of South America from November 2023 to April 2024, affecting many equines and huma...

ViralFlow v1.0 is a computational workflow developed for viral genomic surveillance. Several key changes turned ViralFlow into a general-purpose reference-based genome assembler for all viruses with an available reference genome. New virus-agnostic modules were implemented to further study nucleotide and amino acid mutations. ViralFlow v1.0 runs on...

Horizontal transfer is a phenomenon of genetic material transmission between species with no parental relationship. It has been characterized among several major branches of life, including among prokaryotes, viruses and eukaryotes. Genetic elements derived from horizontal transfer are known as Endogenous Bacterial Elements and Endogenous Viral Ele...

Dengue virus (DENV) is currently causing epidemics of unprecedented scope in endemic settings and expanding to new geographical areas. It is therefore critical to track this virus using genomic surveillance. However, the complex patterns of viral genomic diversity make it challenging to use the existing genotype classification system. Here we propo...

Recombination plays a crucial role in the evolution of SARS-CoV-2. The Omicron XBB* recombinant lineages are a noteworthy example, as they have been the dominant SARS-CoV-2 variant worldwide in the first half of 2023. Since November 2023, a new recombinant lineage between Omicron subvariants XBB and BA.2.86, designated XDR, has been detected mainly...

We present the genome sequence, organization and evidence of persistence of a new picornavirus infecting the flatworm Stenostomum leucops . The complete genome sequence belongs to a virus with a positive single-stranded RNA genome encoding three open reading frames (ORFs) flanked by untranslated regions and polyadenylated termination. The ORFs enco...

SARS-CoV-2 virus emerged as a new threat to humans and spread around the world, leaving a large death toll. As of January 2023, Brazil is among the countries with the highest number of registered deaths. Nonpharmacological and pharmacological interventions have been heterogeneously implemented in the country, which, associated with large socioecono...

During the ongoing western equine encephalitis virus (WEEV) outbreak in South America, we described three fatal cases in horses from Rio Grande do Sul, Brazil. We sequenced WEEV strains and identified a novel lineage causing these cases. Continued surveillance and horse immunization are needed to mitigate the WEEV burden.

The highly pathogenic avian influenza viruses of the clade 2.3.4.4b have caused unprecedented deaths in South American wild birds, poultry, and marine mammals. In September 2023, pinnipeds and seabirds appeared dead on the Uruguayan Atlantic coast. Sixteen influenza virus strains were characterized by real-time reverse transcription PCR and genome...

The Red Queen Hypothesis (RQH), derived from Lewis Carroll’s “Through the Looking-Glass”, postulates that organisms must continually adapt in response to each other to maintain relative fitness. Within the context of host-pathogen interactions, the RQH implies an evolutionary arms race, wherein viruses evolve to exploit hosts and hosts evolve to re...

Arbovirus surveillance of wild-caught mosquitoes is an affordable and sensitive means of monitoring virus transmission dynamics at various spatial-temporal scales, and emergence and re-emergence during epidemic and interepidemic periods. A variety of molecular diagnostics for arbovirus screening of mosquitoes (known as xeno-monitoring) are availabl...

Dengue is an arthropod-borne virus with worldwide urban transmission mediated by anthropophilic vectors of the genus Aedes . Currently, there is a substantial genotype diversity that belongs to at least four known serotypes. Tropical regions, where several serotypes cocirculate in the population, are hyperendemic, driving multiple outbreaks with va...

Aedes aegypti and Culex quinquefasciatus mosquitoes are vectors of different arboviruses that cause a large burden of disease in humans worldwide. A key step towards reducing the impact of arboviruses on humans can be achieved through integrated mosquito surveillance and control approaches. We carried out an integrated approach of mosquito surveill...

The surveillance and detection of zoonotic pathogens in animals is essential for predicting disease transmission pathways and the risks of spillover, but challenges include the costs, ethics and technical expertise required for vertebrate trapping, serum sampling and antibody or virus screening. Surveillance using haematophagous arthropods as a sam...

The mobilization of transposable elements (TEs) can either negatively affect the host’s fitness or contribute to the species evolution. TE protein expression is the first stage for transposition, but organisms developed defenses to control it. The intensity of regulatory mechanisms can vary among tissues, and in response to stress, it may facilitat...

Transposable elements are repetitive and mobile DNA segments that can be found in virtually all organisms investigated to date. Their complex structure and variable nature are particularly challenging from the genomic annotation point of view. Many softwares have been developed to automate and facilitate TEs annotation at the genomic level, but the...

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 r...

A Liga Acadêmica de Genética Humana (LAGH) da Universidade Federal de Pernambuco (UFPE) surgiu há dois anos, motivada pelo desejo dos estudantes de se aprofundarem na área da Genética. Ainda em um contexto de ensino remoto, devido à pandemia de COVID-19, a impossibilidade de acesso aos laboratórios da Universidade impulsionou um grupo de cinco estu...

The highly pathogenic avian influenza viruses of the clade 2.3.4.4b have caused unprecedented deaths in South American wild birds, poultry, and marine mammals. In September 2023, pinnipeds and seabirds appeared dead on the Uruguayan Atlantic coast. Sixteen influenza virus strains were characterized by real-time reverse transcription PCR and genome...

https://cienciahoje.org.br/artigo/vigilancia-viral-em-morcegos-no-brasil/#

Dengue virus serotype 2, genotype Cosmopolitan (DENV-2-GII), is one of the most widespread DENV strains globally. In the Americas, DENV-2 epidemics have been dominated by DENV-2 genotype Asian-American (DENV-2-GIII) and the first cases of DENV-2-GII were only described in 2019, in Peru, and in 2021 in Brazil. To gain new information about the circu...

Transposable elements (TEs) are mobile repetitive DNA sequences that can transfer horizontally between species. Due to their mutagenic characteristics, TEs are associated with different evolutionary events, including chromosomal rearrangements that are abundant in the beetle Euchroma gigantea. In order to understand more in depth the impact of TEs...

Among the invasive species known to occur in South America is the bivalve mollusc Limnoperna fortunei, whose presence is linked to several environmental and economic problems. Early detection and mitigation actions are needed to limit its impact in the remaining L. fortunei-free areas. PCR-based molecular methods have become the gold standard metho...

Very important information for genomic surveillance of arbovirus

In late 2021, a new variant of SARS-CoV-2 called Omicron emerged, replacing Delta worldwide. Although it has been associated with a lower risk of hospitalization and severe forms of COVID-19, there is little evidence of its relationship with specific symptoms and viral load. The aim of this study was to verify the relationship between Delta and Omi...

Background: Chikungunya is a mosquito-borne virus that has been causing large outbreaks in the Americas since 2014. In Brazil, Asian-Caribbean (AC) and East-Central-South-African (ECSA) genotypes have been detected and lead to large outbreaks in several Brazilian states. In Rio Grande do Sul (RS), the southernmost state of Brazil, the first cases...

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 re...

The interaction between the dengue virus (DENV) and the human dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) receptor plays a crucial role in viral entry and infection. Understanding the dynamics of this interaction and its evolution over time is essential for comprehending the host-virus relationship and...

Dengue virus serotype 2, genotype Cosmopolitan (DENV-2-GII) is one of the most widespread DENV strains in the globe. However, in the Americas, the first cases of DENV-2-GII were only described in 2019, in Peru, and in 2021 in the Brazilian states of Goias and Acre. To gain new information about the circulation of DENV-2-GII in Brazil, we sequenced...

We characterized 3 autochthonous dengue virus serotype 3 cases and 1 imported case from 2 states in the North and South Regions of Brazil, 15 years after Brazil's last outbreak involving this serotype. We also identified a new Asian lineage recently introduced into the Americas, raising concerns about future outbreaks.

The rapid spread of the SARS-CoV-2 Variant of Concern (VOC) Gamma in Amazonas during early 2021 fueled a second large COVID-19 epidemic wave and raised concern about the potential role of reinfections. Very few cases of reinfection associated with the VOC Gamma have been reported to date, and their potential impact on clinical, immunological, and v...

In 2023, three autochthonous DENV-3 cases were detected in Roraima and one imported case in Parana, fifteen years after the last DENV-3 outbreak in Brazil. Phylogenetic analyses confirmed all belonging to a new Asian lineage recently introduced in the Americas, raising concerns about future large dengue outbreaks in this region.

Hepatitis E virus (HEV) circulation in humans and swine has been extensively studied in South America over the last two decades. Nevertheless, only 2.1% of reported HEV strains are available as complete genome sequences. Therefore, many clinical, epidemiological, and evolutionary aspects of circulating HEV in the continent still need to be clarifie...

The SARS-CoV-2 variants of concern (VOCs) Delta and Omicron spread globally during mid and late 2021, respectively. In this study, we compare the dissemination dynamics of these VOCs in the Amazonas state, one of Brazil’s most heavily affected regions. We sequenced the virus genome from 4128 patients collected in Amazonas between July 1st, 2021, an...

Endogenous virus elements (EVEs) are viral-derived sequences integrated into their host genomes. EVEs of the Jingchuvirales order were detected in a wide range of insect genomes covering several distantly related families. Moreover, Jingchuvirales-derived glycoproteins were recently associated by our group with the origin of a putative new retrovir...

Mayaro virus (MAYV) is transmitted by Haemagogus spp. mosquitoes and has been circulating in Amazon areas in the North and Central West regions of Brazil since the 1980s, with an increase in human case notifications in the last 10 years. MAYV introduction in urban areas is a public health concern as infections can cause severe symptoms similar to o...

Among invasive species known to occur in South America, the bivalve mollusc Limnoperna fortunei , which the presence is linked to several environmental and economic problems. Early detection and mitigation actions are needed to limit its impact in the remaining L. fortunei -free areas. PCR-based molecular methods have become the gold standard metho...

In Dichotomius genus, transposable elements (TE) have been related to chromosome remodeling, genomic evolution, and, possibly, to the speciation process. The objective of this study was to verify the interpopulational and interspecific conservation/variation of Tc1-Mariner elements (possibly autonomous) in Dichotomius species, aiming to identify po...

In recent years, the SARS-CoV-2 viruses emerged and spread around the world, leaving a large death toll and long-lasting impact on survivors. As of January 2023, Brazil is still among the countries with the highest number of registered deaths. This continental-size and pluralistic country experienced a heterogenous implementation of non-pharmacolog...

With the coexistence of multiple lineages and increased international travel, recombination and gene flow are likely to become increasingly important in the adaptive evolution of SARS-CoV-2. These processes could result in genetic introgression and the incipient parallel evolution of multiple recombinant lineages. However, identifying recombinant l...

Bats host a large variety of viruses, including some that may infect other vertebrates and humans. Research on bat-borne viruses attracted significant attention in recent years mainly due to epizootics caused by viruses having bats as hosts. The characterization of the viral communities of bats was then prioritized, but despite increasing efforts,...