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Meningitis is a disease with a global distribution that constitutes a worldwide burden, with viruses as the primary etiologic agents. The range of viral meningitis severity depends mainly on age, immune status and etiological agent. The aim of this work was to investigate the suspected cases of viral meningitis using molecular techniques to confirm the viral infection. The diagnosed virus was correlated with clinical findings and cytochemical parameters in cerebrospinal liquid (CSF) of patients. CSF of 70 children with the presumptive diagnosis of viral meningitis was analyzed by real time PCR (qPCR). Viruses were identified by qPCR in 44 CSF samples (62.9%). Among them, 31 were identified as Enterovirus (ENTV) (70.4%), six as Human herpes virus 3 (HHV-3) (13.6%), five as Dengue virus (DENV) (11.7%), one as Human herpes virus 1–2 (2.3%) and one as Human herpes virus 5 (2.3%). Patients in the HHV-positive groups had increased percentage of polymorphonuclear neutrophils (PMN) (mean of 81%) while the groups of patients with DENV and ENTV had a mean of 30.9%. This study contributes to the knowledge of the epidemiological distribution of viral agents in CNS infections in children. In addition, it raises the relevance of DENV as an agent of CNS infection, and reinforces the importance for molecular in the cases of CNV infection. [ABSTRACT FROM AUTHOR]

New representatives of the phylum Nucleocytoviricota have been rapidly described in the last decade. Despite this, not all viruses of this phylum are allocated to recognized taxonomic families, as is the case for orpheovirus, pithovirus, and cedratvirus, which form the proposed family Pithoviridae. In this study, we performed comprehensive comparative genomic analyses of 8 pithovirus-like isolates, aiming to understand their common traits and evolutionary history. Structural and functional genome annotation was performed de novo for all the viruses, which served as a reference for pangenome construction. The synteny analysis showed substantial differences in genome organization between these viruses, with very few and short syntenic blocks shared between orpheovirus and its relatives. It was possible to observe an open pangenome with a significant increase in the slope when orpheovirus was added, alongside a decrease in the core genome. Network analysis placed orpheovirus as a distant and major hub with a large fraction of unique clusters of orthologs, indicating a distant relationship between this virus and its relatives, with only a few shared genes. Additionally, phylogenetic analyses of strict core genes shared with other viruses of the phylum reinforced the divergence of orpheovirus from pithoviruses and cedratviruses. Altogether, our results indicate that although pithovirus-like isolates share common features, this group of ovoid-shaped giant viruses presents substantial differences in gene contents, genomic architectures, and the phylogenetic history of several core genes. Our data indicate that orpheovirus is an evolutionarily divergent viral entity, suggesting its allocation to a different viral family, Orpheoviridae. [ABSTRACT FROM AUTHOR]

Phylogenetic analysis of 34 monkeypox virus genome sequences isolated from patients in Minas Gerais, Brazil, revealed initial importation events in early June 2022, then community transmission within the state. All generated genomes belonged to the B.1 lineage responsible for a global mpox outbreak. These findings can inform public health measures. [ABSTRACT FROM AUTHOR]

The Orthopoxvirus (OPV) genus of the Poxviridae family contains several human pathogens, including Vaccinia virus (VACV), which have been implicating in outbreaks of a zoonotic disease called Bovine Vaccinia in Brazil. So far, no approved treatment exists for OPV infections, but ST-246 and Cidofovir (CDV) are now in clinical development. Therefore, the objective of this work was to evaluate the susceptibility of five strains of Brazilian VACV (Br-VACV) to ST-246 and Cidofovir. The susceptibility of these strains to both drugs was evaluated by plaque reduction assay, extracellular virus's quantification in the presence of ST-246 and one-step growth curve in cells treated with CDV. Besides that, the ORFs F13L and E9L were sequenced for searching of polymorphisms associated with drug resistance. The effective concentration of 50% (EC 50 ) from both drugs varies significantly for different strains (from 0.0054 to 0.051 μM for ST-246 and from 27.14 to 61.23 μM for CDV). ST-246 strongly inhibits the production of extracellular virus for all isolates in concentrations as low as 0.1 μM and it was observed a relevant decrease of progeny production for all Br-VACV after CDV treatment. Sequencing of the F13L and E9L ORFs showed that Br-VACV do not present the polymorphism(s) associated with resistance to ST-246 and CDV. Taken together, our results showed that ST-246 and CDV are effective against diverse, wild VACV strains and that the susceptibility of Br-VACV to these drugs mirrored the phylogenetic split of these isolates into two groups. Thus, both ST-246 and CDV are of great interest as compounds to treat individuals during Bovine Vaccinia outbreaks in Brazil. [ABSTRACT FROM AUTHOR]

Vaccinia virus (VACV) is the causative agent of an emerging viral zoonosis called bovine vaccinia (BV). Several studies have documented characteristics of VACV infections in Brazil; however, the manner in which this virus is maintained in wildlife remains unknown. This work investigated the presence of viral DNA and anti-orthopoxvirus (OPXV) antibodies in samples collected from small mammals in a VACV-endemic area in Minas Gerais, Brazil, in the absence of current outbreaks. Samples did not show amplification of OPXV DNA in molecular tests. However, 5/142 serum samples demonstrated the presence of anti-OPXV neutralizing antibodies in serological tests. These data reinforce the involvement of small mammals in the natural cycle of VACV, highlighting the need for further ecological studies to better understand how this virus is maintained in nature and to develop measures to prevent BV outbreaks. [ABSTRACT FROM AUTHOR]

Abstract: Acanthamoeba polyphaga mimivirus (APMV) is a giant, double-stranded virus of the Mimiviridae family that was discovered in 2003. Recent studies have shown that this virus is able to replicate in murine and human phagocytes and might be considered a putative human pathogen that causes pneumonia. However, there is little data regarding APMV and its host defense relationship. In the present study, we investigated how some components of the interferon (IFN) system are stimulated by APMV in human peripheral blood mononuclear cells (PBMCs) and how APMV replication is affected by IFN treatment. Our results demonstrated that APMV is able to replicate in human PBMCs, inducing type I Interferons (IFNs) but inhibiting interferon stimulated genes (ISG) induction by viroceptor and STAT-1 and STAT-2 dephosphorylation independent mechanisms. We also showed that APMV is resistant to the antiviral action of interferon-alpha2 (IFNA2) but is sensitive to the antiviral action of interferon-beta (IFNB1). Our results demonstrated the productive infection of professional phagocytes with APMV and showed that this virus is recognized by the immune system of vertebrates and inhibits it. It provides the first data regarding APMV and the IFN system interaction and raise new and relevant evolutional questions about the relationship between APMV and vertebrate hosts. [Copyright &y& Elsevier]

Since 1999, several Vaccinia virus (VACV) isolates, the etiological agents of bovine vaccinia (BV), have been frequently isolated and characterized with various biological and molecular methods. The results from these approaches have grouped these VACV isolates into two different clusters. This dichotomy has elicited debates surrounding the origin of the Brazilian VACV and its epidemiological significance. To ascertain vital information to settle these debates, we and other research groups have made efforts to identify molecular markers to discriminate VACV from other viruses of the genus Orthopoxvirus (OPV) and other VACV-BR groups. In this way, some genes have been identified as useful markers to discriminate between the VACV-BR groups. However, new markers are needed to infer ancestry and to correlate each sample or group with its unique epidemiological and biological features. The aims of this work were to characterize a new VACV isolate (VACV DMTV- 2005) molecularly and biologically using conserved and non-conserved gene analyses for phylogenetic inference and to search for new genes that would elucidate the VACV-BR dichotomy. The VACV DMTV-2005 isolate reported in this study is biologically and phylogenetically clustered with other strains of Group 1 VACV-BR, the most prevalent VACV group that was isolated during the bovine vaccinia outbreaks in Brazil. Sequence analysis of C23L, the gene that encodes for the CCchemokine- binding protein, revealed a ten-nucleotide deletion, which is a new Group 1 Brazilian VACV genetic marker. This deletion in the C23L open reading frame produces a premature stop-codon that is shared by all Group 1 VACV-BR strains and may also reflect the VACV-BR dichotomy; the deletion can also be considered to be a putative genetic marker for nonvirulent Brazilian VACV isolates and may be used for the detection and molecular characterization of new isolates. [ABSTRACT FROM AUTHOR]

We report a 3-year-old child who was hospitalized because of severe manifestations of the central nervous system. The child died after 6 days of hospitalization. Analysis of postmortem cerebrospinal fluid showed the presence of yellow fever virus RNA. Nucleotide sequencing confirmed that the virus was wild-type yellow fever virus. [ABSTRACT FROM AUTHOR]

Background: Since the discovery of giant viruses infecting amoebae in 2003, many dogmas of virology have been revised and the search for these viruses has been intensified. Over the last few years, several new groups of these viruses have been discovered in various types of samples and environments. In this work, we describe the isolation of 68 giant viruses of amoeba obtained from environmental samples from Brazil and Antarctica. Methods: Isolated viruses were identified by hemacolor staining, PCR assays and electron microscopy (scanning and/or transmission). Results: A total of 64 viruses belonging to the Mimiviridae family were isolated (26 from lineage A, 13 from lineage B, 2 from lineage C and 23 from unidentified lineages) from different types of samples, including marine water from Antarctica, thus being the first mimiviruses isolated in this extreme environment to date. Furthermore, a marseillevirus was isolated from sewage samples along with two pandoraviruses and a cedratvirus (the third to be isolated in the world so far). Conclusions: Considering the different type of samples, we found a higher number of viral groups in sewage samples. Our results reinforce the importance of prospective studies in different environmental samples, therefore improving our comprehension about the circulation anddiversity of these viruses in nature. [ABSTRACT FROM AUTHOR]

The gastrointestinal tract of vertebrates harbors one of the most complex ecosystems known in microbial ecology and this indigenous microbiota almost always has a profound influence on host-parasite relationships, which can enhance or reduce the pathology of the infection. In this context, the impact of the microbiota during the infection of several viral groups remains poorly studied, including the family Poxviridae. Vaccinia virus (VACV) is a member of this family and is the causative agent of bovine vaccinia, responsible for outbreaks that affect bovines and humans. To determine the influence of the microbiota in the development of the disease caused by VACV, a comparative study using a murine model was performed. Germ-free and conventional, 6- to 7-week-old Swiss NIH mice were infected by tail scarification and intranasally with VACV. Moreover, immunosuppression and microbiota reposition were performed, to establish the interactions among the host's immune system, microbiota and VACV. The data demonstrate that the microbiota is essential for the effective immune response of mice against VACV in intranasal inoculation and to control the virus at the primary site of infection. Furthermore, this study is the first to show that Swiss conventional mice are refractory to the intranasal infection of VACV. [ABSTRACT FROM AUTHOR]