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The whole genome sequence of a low pathogenicity avian influenza virus (H6N2) was sequenced from a Brazilian teal (Amazonetta brasiliensis) in Brazil, 2023. Phylogenetic analysis of the whole genome revealed a distinct genome pertaining to South American LPAIV from 2014 to 2016, indicating extensive circulation among South American wild birds.

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Even though Brazil is a country where the dengue virus (DENV) is endemic, until recently, Southern states did not have significant viral circulation, such as Rio Grande do Sul (RS), and some municipalities were even considered dengue-free. During 2022, these places have shown a sharp increase in the incidence of the disease, apparently following a worldwide growth pattern. Therefore, in this study, we monitor and characterize the genetic diversity of DENV circulating in southern Brazil through next-generation sequencing during an outbreak in 2022. We generated 70 DENV-1 genome sequences, all characterized as genotype V, divided into two clade clusters in the L1 lineage. Furthermore, unique mutations have been described in each clade of L1 lineage. Our results are essential in managing outbreaks since these data provide important information during the emergence of DENV circulation in RS. Since the south of Brazil has a lower viral circulation when compared to other Brazilian states, RS still lacks data that can help in understanding the transmission, dissemination, and evolution of the dengue virus. Hence, genomic surveillance efforts are essential to increase the accuracy of preventive actions and to control viral dissemination.

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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 were reported in 2016. OBJECTIVES AND METHODS: We employed genome sequencing and epidemiological investigation to characterise the Chikungunya fever (CHIKF) burden in RS between 2017-2021. FINDINGS: We detected an increasing CHIKF burden linked to travel associated introductions and communitary transmission of distinct lineages of the ECSA genotype during this period. MAIN CONCLUSIONS: Until 2020, CHIKV introductions were most travel associated and transmission was limited. Then, in 2021, the largest outbreak occurred in the state associated with the introduction of a new ECSA lineage. CHIKV outbreaks are likely to occur in the near future due to abundant competent vectors and a susceptible population, exposing more than 11 million inhabitants to an increasing infection risk.

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New viruses of the Picornavirales order have been discovered with the increase in the number of sequences obtained by high-throughput sequencing, as well as human stool-associated RNA virus (husavirus [HuV]), found in human stool samples. However, there is much to be clarified about HuV. Its cellular host, evolutionary history, and other biological characteristics are still unknown. Therefore, samples collected from human beings and environmental samples in a watershed in Southern Brazil were processed for the metagenomic library. Upon metagenomic analysis, we identified a HuV (husavirus LMM_67754 OP019707) genome with 8,846 bp, which was reported for the first time in Southern Brazil. The new genome presents only 37% of nucleotide identity with Brazilian strains and more than 90% with genomes from China, Vietnam, Venezuela, and the Netherlands. The HuV phylogeny presents significant differences among genomes, probably because multiple introductions of the virus may have occurred. Many questions still need to be answered about HuV. Therefore, more sequences and studies on this virus are necessary to improve the comprehension of the unknown origin of Picornavirales.

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The hospital environment can be considered a high risk for the occurrence of SARS-CoV-2 transmission outbreaks, either for health professionals who are directly involved in the care of suspected or confirmed cases of the disease, or for patients, for being in an environment more vulnerable to the acquisition of nosocomial infections. In this molecular epidemiology study, we aimed to analyze the occurrence and transmission dynamics of SARS-CoV-2 in outbreaks and local chains of transmission in a large tertiary teaching hospital in southern Brazil, in addition to verifying circulating strains and their epidemiological relation in the local context, from September 21, 2020 to October 5, 2021. Positive samples involved in COVID-19 clusters or outbreaks were analyzed using clinical, epidemiological and genomic data. Different lineages and sublineages among patients in the same room were observed. Most patients had their first clinical manifestation, evidence of suspicion, and diagnostic confirmation within 7-14 days or >14 days after hospital admission. The patients who have contact with confirmed cases of COVID-19 spent, on average, 6.28 days in the same environment until the positive test. There was a significant association between the outcome and the number of vaccine doses (p < 0.05), where those who received two doses presented a lower occurrence of death. There was a total replacement of variant of concern (VOC) Gamma by VOC Delta from August 2021 at the study site. Although the epidemiological analysis indicates nosocomial infections, through genomic sequencing, it was established that most of the hospital outbreaks had different origins. These findings highlight the utility of integrating epidemiological and genomic data to identify possible routes of viral entry and dissemination.

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ABSTRACT New viruses of the Picornavirales order have been discovered with the increase in the number of sequences obtained by high-throughput sequencing, as well as human stool-associated RNA virus (husavirus [HuV]), found in human stool samples. However, there is much to be clarified about HuV. Its cellular host, evolutionary history, and other biological characteristics are still unknown. Therefore, samples collected from human beings and environmental samples in a watershed in Southern Brazil were processed for the metagenomic library. Upon metagenomic analysis, we identified a HuV (husavirus LMM_67754 OP019707) genome with 8,846 bp, which was reported for the first time in Southern Brazil. The new genome presents only 37% of nucleotide identity with Brazilian strains and more than 90% with genomes from China, Vietnam, Venezuela, and the Netherlands. The HuV phylogeny presents significant differences among genomes, probably because multiple introductions of the virus may have occurred. Many questions still need to be answered about HuV. Therefore, more sequences and studies on this virus are necessary to improve the comprehension of the unknown origin of Picornavirales.

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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 were reported in 2016. OBJECTIVES AND METHODS We employed genome sequencing and epidemiological investigation to characterise the Chikungunya fever (CHIKF) burden in RS between 2017-2021. FINDINGS We detected an increasing CHIKF burden linked to travel associated introductions and communitary transmission of distinct lineages of the ECSA genotype during this period. MAIN CONCLUSIONS Until 2020, CHIKV introductions were most travel associated and transmission was limited. Then, in 2021, the largest outbreak occurred in the state associated with the introduction of a new ECSA lineage. CHIKV outbreaks are likely to occur in the near future due to abundant competent vectors and a susceptible population, exposing more than 11 million inhabitants to an increasing infection risk.

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Recently, SARS-CoV-2 Omicron variant (B.1.1.529) was first identified in Botswana in November 2021. In a short period of time, this highly mutated variant replaced the previous dominant Delta variant, causing an exponential increase in the number of COVID-19 cases, resulting in a new wave of pandemic. This current research article aims to analyze and summarize information about the genetic characteristics, amino acid mutations and epidemiological data providing scientific findings to enrich the SARS-CoV-2 knowledge. More importantly, we describe here, for the first time, the identification of a new Omicron variant of concern: Omicron-L452R in Brazil.

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The emergence of Variants of Concern (VOC) presenting an unusual number of new mutations is one of the most remarkable features of SARS-CoV-2. The Delta variant, since its appearance, replaced the VOC Gamma, which was responsible for the major COVID-19 wave in Brazil. In this study, we performed a Delta whole-genome sequencing of 183 samples as part of a major genomic surveillance study performed since the beginning of the pandemic. Here, we showed an emergence, widespread dispersion and consolidation of the Delta variant in Rio Grande do Sul State, completely replacing the Gamma variant in a four to five months period. Performing the phylogenetic and phylodynamic analysis, the majority of the sequences generated herein were classified as AY.99.2, AY.99.2-like and AY.101. AY.99.2 Delta-related lineage has been widely reported in Brazil and in the Americas as well. Altogether, our findings provided a mutational profile of the sequences and presented high substitutions per site in the root-to-tip phylogenetic tree, corroborating studies that show the high mutational rate of SARS-CoV-2 over time.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the pandemic that started in late 2019 and still affects people's lives all over the world. Lack of protective immunity after primary infection has been involved with reported reinfection cases by SARS-CoV-2. In this study, we described two cases of reinfection caused by non-VOC (Variants of Concern) strains in southern Brazil, being one patient a healthcare worker. The four samples previously positive for SARS-CoV-2 by real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) were sequenced by a high-performance platform and the genomic analysis confirmed that lineages responsible for infections were B.1.91 and B.1.1.33 (patient 1), and B.1.1.33 and B.1.1.28 (patient 2). The interval between the two positive RT-qPCR for patients 1 and 2 was 45 and 61 days, respectively. This data shows that patients may be reinfected even by very closely related SARS-CoV-2 lineages.

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Multiple variants of the Severe Acute Respiratory Syndrome coronavirus 2 virus (SARS-CoV-2) have been constantly reported across the world. The B.1.1.28 lineage has been evolving in Brazil since February 2020 and originated the P.1 variant of concern (VOC), recently named as the Gamma variant by the newly WHO nomenclature proposal, and P.2 as a variant of interest (VOI). Here we describe an early case of P.1 primary infection in Southern Brazil in late November 2020, soon after the emergence of the variant in Manaus, Northern Brazil. The same male patient was reinfected by another B.1.1.28 variant, namely P.2, in March, 2021. The genomic analysis confirmed genetically significant differences between the two viruses recovered in both infections, the P.1 lineage in the first episode and P.2 in the reinfection. Due the very early detection of P.1, we have also investigated the circulation of P.1 in the same region by differential RT-qPCR, showing that this was an isolated case of P.1 at the time of detection, and this variant has disseminated and became prominent from late January to the end of March, 2021. SARS-CoV-2 recent reports of reinfection have raised critical questions on whether and how well a first infection protects against reinfection.

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