Distribution of species enterovirus B in patients with central nervous system infections in São Paulo State, Brazil

A 3-month-old neonatal rhesus macaque HFMD model caused by coxsackievirus B1 infection and viral tissue tropism

Coxsackievirus B1 (CVB1), an enterovirus with multiple clinical presentations, has been associated with potential long-term consequences, including hand, foot, and mouth disease (HFMD), in some patients. However, the related animal models, transmission dynamics, and long-term tissue tropism of CVB1 have not been systematically characterized. In this study, we established a model of CVB1 respiratory infection in rhesus macaques and evaluated the clinical symptoms, viral load, and immune levels during the acute phase (0-14 days) and long-term recovery phase (15-30 days). We also investigated the distribution, viral clearance, and pathology during the long-term recovery period using 35 postmortem rhesus macaque tissue samples collected at 30 days postinfection (d.p.i.). The results showed that the infected rhesus macaques were susceptible to CVB1 and exhibited HFMD symptoms, viral clearance, altered cytokine levels, and the presence of neutralizing antibodies. Autopsy revealed positive viral loads in the heart, spleen, pancreas, soft palate, and olfactory bulb tissues. HE staining demonstrated pathological damage to the liver, spleen, lung, soft palate, and tracheal epithelium. At 30 d.p.i., viral antigens were detected in visceral, immune, respiratory, and muscle tissues but not in intestinal or neural tissues. Brain tissue examination revealed viral meningitis-like changes, and CVB1 antigen expression was detected in occipital, pontine, cerebellar, and spinal cord tissues at 30 d.p.i. This study provides the first insights into CVB1 pathogenesis in a nonhuman primate model of HFMD and confirms that CVB1 exhibits tissue tropism following long-term infection.

Evaluation of enterovirus concentration, species identification, and cerebrospinal fluid parameters in patients of different ages with aseptic meningitis in São Paulo, Brazil

Human enteroviruses (EV) are the most common cause of aseptic meningitis worldwide. Data on EV viral load in cerebrospinal fluid (CSF) and related epidemiological studies are scarce in Brazil. This study investigated the influence of EV viral load on CSF parameters, as well as identifying the involved species. CSF samples were collected in 2018-2019 from 140 individuals at The Hospital das Clínicas, São Paulo. The EV viral load was determined using real-time quantitative polymerase chain reaction, while EV species were identified by 5'UTR region sequencing. Median viral load was 5.72 log10  copies/mL and did not differ by subjects' age and EV species. Pleocytosis was observed in 94.3% of cases, with the highest white blood cell (WBC) counts in younger individuals. Viral load and WBC count were correlated in children (p = 0.0172). Elevated lactate levels were observed in 60% of cases and correlated with the viral load in preteen-teenagers (p = 0.0120) and adults (p = 0.0184). Most individuals had normal total protein levels (70.7%), with higher in preteen-teenagers and adults (p < 0.0001). By sequencing, 8.2% were identified as EV species A and 91.8% as species B. Age-specific variations in CSF characteristics suggest distinct inflammatory responses in each group.

Drug Repositioning for Hand, Foot, and Mouth Disease

Hand, foot, and mouth disease (HFMD) is a highly contagious disease in children caused by a group of enteroviruses. HFMD currently presents a major threat to infants and young children because of a lack of antiviral drugs in clinical practice. Drug repositioning is an attractive drug discovery strategy aimed at identifying and developing new drugs for diseases. Notably, repositioning of well-characterized therapeutics, including either approved or investigational drugs, is becoming a potential strategy to identify new treatments for virus infections. Various types of drugs, including antibacterial, cardiovascular, and anticancer agents, have been studied in relation to their therapeutic potential to treat HFMD. In this review, we summarize the major outbreaks of HFMD and the progress in drug repositioning to treat this disease. We also discuss the structural features and mode of action of these repositioned drugs and highlight the opportunities and challenges of drug repositioning for HFMD.

Atomic Structures of Coxsackievirus B5 Provide Key Information on Viral Evolution and Survival

Coxsackie virus B5 (CVB5), a main serotype in human Enterovirus B (EVB), can cause severe viral encephalitis and aseptic meningitis among infants and children. Currently, there is no approved vaccine or antiviral therapy available against CVB5 infection. Here, we determined the atomic structures of CVB5 in three forms: mature full (F) particle (2.73 Å), intermediate altered (A) particle (2.81 Å), and procapsid empty (E) particle (2.95 Å). Structural analysis of F particle of CVB5 unveiled similar structures of “canyon,” “puff,” and “knob” as those other EV-Bs. We observed structural rearrangements that are alike during the transition from F to A particle, indicative of similar antigenicity, cell entry, and uncoating mechanisms shared by all EV-Bs. Further comparison of structures and sequences among all structure-known EV-Bs revealed that while the residues targeted by neutralizing MAbs are diversified and drive the evolution of EV-Bs, the relative conserved residues recognized by uncoating receptors could serve as the basis for the development of antiviral vaccines and therapeutics.

IMPORTANCE As one of the main serotypes in Enterovirus B, CVB5 has been commonly reported in recent years. The atomic structures of CVB5 shown here revealed classical features found in EV-Bs and the structural rearrangement occurring during particle expansion and uncoating. Also, structure- and sequence-based comparison between CVB5 and other structure-known EV-Bs screened out key domains important for viral evolution and survival. All these provide insights into the development of vaccine and therapeutics for EV-Bs.

Molecular typing of enteroviruses and parechoviruses in acute flaccid paralysis patients in Iran in 2019

Enteroviruses (EVs) and parechoviruses (PeVs) are among the viral pathogens that can cause acute flaccid paralysis (AFP). There is not sufficient information about direct detection of EVs and PeVs in AFP patients in Iran. The aim of this study was to conduct a one-year study for direct detection and molecular typing of EVs and PeVs from stool samples of AFP patients in Iran. One hundred stool samples from polio-negative AFP patients who were referred to the Iran National Polio Laboratory were randomly chosen and analyzed during 2019. A one-step TaqMan probe-based real-time RT-PCR assay targeting the 5'-untranslated region (5' -UTR) was used to screen for EVs and PeVs. All positive samples were genotyped by direct sequencing, targeting the VP1 region of the genome. In total, twelve (12%) and four (4%) stool samples from polio-negative AFP children were positive for EVs and PeVs, respectively. Sequence analysis revealed the presence of echovirus 2 (E2), echovirus 13 (E13), echovirus 25 (E25), echovirus 30 (E30), coxsackievirus A2 (CVA2), coxsackievirus A9 (CVA9), coxsackievirus A16 (CVA16), human enterovirus A76 (HEV-A76), and human parechovirus 1 (HPeV1) in children with AFP-like symptoms. Phylogenetic analysis showed that E2 strains clustered together with the strains circulating in the Netherlands during 2014, whereas the PeV strains belonged to different lineages. This study demonstrates that different EV types are associated with AFP cases in Iran. However, the frequency of association of PeVs with AFP cases appears to be low.

Composition of Eukaryotic Viruses and Bacteriophages in Individuals with Acute Gastroenteritis

Metagenomics based on the next-generation sequencing (NGS) technique is a target-independent assay that enables the simultaneous detection and genomic characterization of all viruses present in a sample. There is a limited amount of data about the virome of individuals with gastroenteritis (GI). In this study, the enteric virome of 250 individuals (92% were children under 5 years old) with GI living in the northeastern and northern regions of Brazil was characterized. Fecal samples were subjected to NGS, and the metagenomic analysis of virus-like particles (VLPs) identified 11 viral DNA families and 12 viral RNA families. As expected, the highest percentage of viral sequences detected were those commonly associated with GI, including rotavirus, adenovirus, norovirus (94.8%, 82% and 71.2%, respectively). The most common co-occurrences, in a single individual, were the combinations of rotavirus-adenovirus, rotavirus-norovirus, and norovirus-adenovirus (78%, 69%, and 62%, respectively). In the same way, common fecal-emerging human viruses were also detected, such as parechovirus, bocaporvirus, cosavirus, picobirnavirus, cardiovirus, salivirus, and Aichivirus. In addition, viruses that infect plants, nematodes, fungi, protists, animals, and arthropods could be identified. A large number of unclassified viral contigs were also identified. We show that the metagenomics approach is a powerful and promising tool for the detection and characterization of different viruses in clinical GI samples.

Coxsackievirus B5 virus-like particle vaccine exhibits greater immunogenicity and immunoprotection than its inactivated counterpart in mice

Coxsackievirus B group 5 (CVB5) represents one of the major pathogens that cause diseases such as hand, foot and mouth disease (HFMD) and aseptic meningitis et al. Currently, no specific drugs and vaccines are available, and a safe and effective CVB5 vaccine is of great value for control of the diseases. In this study, CVB5 P1 precursor and 3CD protease were co-expressed in Sf9 cells by using a baculovirus expression system. The P1 was processed by 3CD and self-assembled into CVB5 virus-like particles (VLPs). VP1 and VP3 capsid proteins of CVB5 could be detected by SDS-PAGE and Western blotting. Transmission electron microscopy revealed that the CVB5 VLPs were spherical particles with a diameter of about 30 nm, mimicking wild-type CVB5 virus. Our study showed that the total IgG and neutralizing antibodies induced by CVB5 VLPs were higher than those induced by inactivated vaccine. More importantly, the CVB5 VLPs conferred full protection to the CVB5-challenged suckling mice via passive immunity while protection efficiency of the inactivated vaccine was only 80%. The CVB5 VLPs vaccine could protect the limb muscles, brain, and heart tissues of suckling mice from CVB5-induced damage. These results demonstrated that the CVB5 VLPs vaccine possessed stronger immunogenicity and provided more robust immunoprotection than the inactivated CVB5 vaccine, suggesting that the CVB5 VLPs promise to be a CVB5 vaccine candidate in future.

The Most Influential Papers in Infectious Meningitis Research: A Bibliometric Study

Background

Bibliometric analyses allow detecting citation trends within a field, including assessments of the most cited journals, countries, institutions, topics, types of study, and authors.

Objective

The aim of this study was to perform a bibliometric analysis of the 100 most cited papers within infectious meningitis research.

Materials and Methods

The 100 most cited publications and their data were retrieved from Scopus and Web of Science during 2019.

Results

The New England Journal of Medicine had the greatest number of articles (27) and citations (12,266) in the top 100. Articles were mainly published after the late 1980s. Bacteria were the most discussed agents (72 articles and 26,362 citations), but Cryptococcus sp represented the most-discussed single agent (16 articles and 6,617 citations). Primary research represented 70 articles and 25,754 citations. Among them, the most discussed topic was Clinical Features and Diagnosis/Outcomes (22 articles and 8,325 citations). Among the 27 secondary research articles, the most common type of study was Narrative Review (18 articles and 5,685 citations). The United States was the country with the greatest number of articles (56) and citations (21,388). Centers for Disease Control and Prevention (CDC) and Yale University had the greatest number of articles (six each), being CDC the most cited (3,559).

Conclusions

The most cited articles within meningitis research are primary research studies, more frequently published in high IF journals and by North American institutions. Bacterial meningitis comprises the majority of publications. The articles were mainly published after the AIDS pandemic and after the implementation of the main vaccines for meningitis.

Viral and Prion Infections Associated with Central Nervous System Syndromes in Brazil

Virus-induced infections of the central nervous system (CNS) are among the most serious problems in public health and can be associated with high rates of morbidity and mortality, mainly in low- and middle-income countries, where these manifestations have been neglected. Typically, herpes simplex virus 1 and 2, varicella-zoster, and enterovirus are responsible for a high number of cases in immunocompetent hosts, whereas other herpesviruses (for example, cytomegalovirus) are the most common in immunocompromised individuals. Arboviruses have also been associated with outbreaks with a high burden of neurological disorders, such as the Zika virus epidemic in Brazil. There is a current lack of understanding in Brazil about the most common viruses involved in CNS infections. In this review, we briefly summarize the most recent studies and findings associated with the CNS, in addition to epidemiological data that provide extensive information on the circulation and diversity of the most common neuro-invasive viruses in Brazil. We also highlight important aspects of the prion-associated diseases. This review provides readers with better knowledge of virus-associated CNS infections. A deeper understanding of these infections will support the improvement of the current surveillance strategies to allow the timely monitoring of the emergence/re-emergence of neurotropic viruses.

Coxsackievirus B3-Its Potential as an Oncolytic Virus

Oncolytic virotherapy represents one of the most advanced strategies to treat otherwise untreatable types of cancer. Despite encouraging developments in recent years, the limited fraction of patients responding to therapy has demonstrated the need to search for new suitable viruses. Coxsackievirus B3 (CVB3) is a promising novel candidate with particularly valuable features. Its entry receptor, the coxsackievirus and adenovirus receptor (CAR), and heparan sulfate, which is used for cellular entry by some CVB3 variants, are highly expressed on various cancer types. Consequently, CVB3 has broad anti-tumor activity, as shown in various xenograft and syngeneic mouse tumor models. In addition to direct tumor cell killing the virus induces a strong immune response against the tumor, which contributes to a substantial increase in the efficiency of the treatment. The toxicity of oncolytic CVB3 in healthy tissues is variable and depends on the virus strain. It can be abrogated by genetic engineering the virus with target sites of microRNAs. In this review, we present an overview of the current status of the development of CVB3 as an oncolytic virus and outline which steps still need to be accomplished to develop CVB3 as a therapeutic agent for clinical use in cancer treatment.

High Heterogeneity of Echoviruses in Brazilian Children with Acute Gastroenteritis

Echoviruses (E) are a diverse group of viruses responsible for various pathological conditions in humans including aseptic meningitis, myocarditis, and acute flaccid paralysis. The detection and identification of echovirus genotypes in clinical samples is challenging due to its high genetic diversity. Here, we report the complete genome sequences of nine echoviruses, obtained by next-generation sequencing of 238 fecal samples from individuals with gastroenteritis in regions of Brazil. Detected viruses were classified into six genotypes: Three E1 sequences (BRA/TO-028, BRA/TO-069 and BRA/TO-236), one E3 (BRA/TO-018), one E11 (BRA/TO-086), one E20 (BRA/TO-016), two E29 (BRA/TO-030 and BRA/TO-193), and one E30 sequence (BRA/TO-032). Phylogenetic analysis indicated that the echoviruses E1 and E29 circulating in Brazil are divergent from strains circulating worldwide. The genotype diversity identified in our study may under-represent the total echovirus diversity in Brazil because of the small sample size and the restricted geographical distribution covered by the survey.