Community-acquired infectious meningoencephalitis is associated with high rates of mortality and morbidity, compounded by limited access to diagnostic resources. The current study assessed acute central nervous system (CNS) infections in patients with meningoencephalitis enrolled in a hospital-based diagnostic surveillance study in São Paulo, Brazil. Cerebrospinal fluid (CSF) was collected from 600 patients between March 2018 and November 2019 and initially screened for a broad range of pathogens according to a local diagnostic algorithm. Standard microbiological and molecular diagnostic methods were applied. Metagenomic sequencing was used as a complementary approach to investigating etiology in instances where no pathogen was initially identified. Standard testing identified infectious etiologies in 292 patients (48.6%), with 227 (77.7%) confirmed as viral infections, predominantly caused by enteroviruses ( n = 144) and herpesviruses ( n = 40). Nonviral agents were identified in 65 patients (22.3%). Metagenomic sequencing (mNGS) of 277 of 308 undiagnosed patients revealed several additional potential etiologies, including Parvovirus B19 , Toxoplasma gondii , Picobirnavirus , other enterovirus species and Vesivirus , the latter being associated with CNS infection for the first time. These findings underscore the complexity of CNS infections and highlight the potential of metagenomics to improve diagnostic accuracy, inform treatment strategies, and support efforts to address future pandemics.

The lower female reproductive tract (FRT) hosts a complex microbial environment, including eukaryotic and prokaryotic viruses (the virome), whose roles in health and disease are not fully understood. This review consolidates findings on FRT virome composition, revealing the presence of various viral families and noting significant gaps in knowledge. Understanding interactions between the virome, microbiome, and immune system will provide novel insights for preventing and managing lower genital tract disorders.

Vaccination is a fundamental tool to prevent SARS-CoV-2 infection and to limit the COVID-19 pandemic. The emergence of SARS-CoV-2 variants with multiple mutations has raised serious concerns about the ability of neutralizing antibody responses elicited by prior vaccination to effectively combat these variants. The neutralizing capacity against the Gamma, Delta and Omicron variants of sera from individuals immunized with the CoronaVac vaccine remains incompletely determined. The present study evaluated 41 health care workers at the Faculdade de Medicina of the Universidade de Sao Paulo, in Sao Paulo, Brazil, naive to previous SARS- CoV-2 infection, who were vaccinated with two doses of the CoronaVac SARS-CoV-2 vaccine 28 days apart. Neutralizing antibody levels against the Gamma, Delta, and Omicron variants were measured at 32 and 186 days after the second vaccination. We also measured neutralizing antibodies against Omicron in 34 of these individuals following a subsequent booster immunization with the Pfizer vaccine. Quantification of neutralizing antibodies was performed using the Cytopathic Effect-based Virus Neutralization test. Neutralization antibody activity against the Gamma, Delta and Omicron variants was observed in 78.0%, 65.9% and 58.5% of serum samples, respectively, obtained at a mean of 32 days after the second immunization. This decreased to 17.1%, 24.4% and 2.4% of sera having activity against Delta, Gamma and Omicron, respectively, at 186 days post-vaccination. The median neutralizing antibody titers at 32 days were 1:40, 1:20 and 1:20 against Gamma, Delta and Omicron, respectively, and decreased to an undetectable median level against all variants at the later time. A booster immunization with the Pfizer vaccine elicited neutralizing antibodies against Omicron in 85% of subjects tested 60 days after vaccination. We conclude that two doses of the CoronaVac vaccine results in limited protection of short duration against the Gamma, Delta and Omicron SARS-CoV-2 variants. A booster dose with the Pfizer vaccine induced antibody neutralizing activity against Omicron in most patients which was measurable 60 days after the booster.

Background: There is scarce information on Varicella–Zoster virus genetic variability in individuals with acute central nervous system infection in Brazil. The objective of this study was the molecular characterization of Varicella–Zoster virus isolates in cerebrospinal fluid from individuals with acute central nervous system infection. Methods: Cerebrospinal fluid samples were collected from individuals evaluated in emergency and community healthcare services in São Paulo, Brazil. Varicella–Zoster virus identification was performed using commercial platforms Biofire-FilmArray Meningitis/Encephalitis (BioMérieux, Craponne, France) and XGEN-UMLTI-N9^® (Mobius Life, Pinhais, Brazil). Positive samples were further characterized as wild-type or vaccine-strain by a real-time polymerase chain reaction assay that targeted a single nucleotide polymorphism in open reading frame 62. We also estimated the mean genetic distance and phylogenetic reconstruction based on open reading frames 22, 38, 54, and 62 in relation to sequences of intercontinentally circulating Varicella–Zoster virus isolates. Results: Among the 600 cerebrospinal fluid samples, we identified Varicella–Zoster virus in 30 (5%) samples. None were positive for the vaccine-strain. Twelve samples were sequenced and phylogenetically classified into Clades 1 (41.7%), 2 (25%), 3 (8.3%), 5 (16.7%), or 6 (8%). Conclusion: Enhanced characterization of circulating Varicella–Zoster virus Clades in Brazil identified previously unreported Clades 2 and 6 as well as three other Clades disseminated intercontinentally. These findings reinforce the importance of Varicella–Zoster virus molecular surveillance in cerebrospinal fluid.

Torquetenovirus (TTV) is a nonpathogenic endogenous virus whose abundance varies with the extent of immune system activation. We determined if the TTV titer in the vagina of pregnant women was associated with vaginal microbiota composition and levels of compounds in vaginal secretions. Vaginal TTV and microbiota composition in 494 second trimester pregnant women were identified by gene amplification and analysis. Vaginal matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMP) and lactic acid isomers were measured by ELISA. Dominance was defined as the relative abundance of a specific bacterium or species at >50% of the total number of bacteria identified. Clinical data were obtained by chart review. The median log₁₀TTV titer was lowest whenLactobacillusspecies other thanL.inerswere dominant (<1.0) as compared to whenL.iners(4.1, p = 0.0001), bacteria other than lactobacilli (4.5, p = 0.0016) or no bacterium (4.7, p = 0.0009) dominated. The TTV titer was inversely proportional toL.crispatusabundance (p<0.0001) and directly proportional to levels ofG.vaginalis(p = 0.0008) andL.iners(p = 0.0010). The TTV titer was proportional to TIMP-1, TIMP-2, MMP-8 and MMP-9 abundance (p≤0.0002) and inversely proportional to the level of D-lactic acid (p = 0.0024). We conclude that the association between variations in the TTV titer and the relative abundance of specific bacterial species and vaginal compounds indicates that local changes in immune status likely influence vaginal fluid composition.

Background: Redondovirus (ReDoV) is a DNA virus present in the respiratory tract of many healthy individuals. Since SARS-CoV-2, the virus responsible for COVID-19, also primarily infects the same site, we evaluated whether ReDoV was present at increased frequency in patients with COVID-19 and influenced infection parameters. Methods: Saliva samples were collected weekly from 59 individuals with COVID-19 and from 132 controls. ReDoV was detected by polymerase chain reaction and the genotypes were identified by metagenomics. Torque Teno Virus (TTV) in these samples were previously reported. Results: ReDoV was detected in saliva more frequently from COVID-19 patients (72.9%) than from controls (50.0%) (p = 0.0015). There were no associations between ReDoV detection and either continuous or intermittent SARS-CoV-2 shedding, the duration of SARS-CoV-2 detection in saliva, patients’ sex or if infection was by the B1 or Gamma strain. The two ReDoV strains, Brisavirus and Vientovirus, were present in equivalent frequencies in ReDoV-positive COVID-19 patients and controls. Phylogenetic analysis suggested that the two ReDoV strains in Brazil were similar to strains previously detected on other continents. Conclusion: ReDoV expression in saliva is increased in males and females in Brazil with mild COVID-19 but its presence does not appear to influence properties of the SARS-CoV-2 infection.