Viruses-Basel最新文献

Background: Tick-borne encephalitis (TBE) virus is transmitted to humans via tick bites and occasionally via the consumption of unpasteurized milk products. According to the literature, the most important driver of TBE emergence and increase in incidence in humans is changes in human behaviour/activities. Method and principal findings: To compensate for the lack of data, expert opinions were gathered to identify the risk factors for exposure to tick bites linked to twenty-eight human activities (professional or recreational) in forests and to target prevention messages at the populations most at risk. Opinions were elicited from a total of twenty-five European experts. Seven criteria were included in the analysis for each activity: frequency, seasonality, duration of exposure, distance covered, degree of contact with vegetation, speed and average level of protection against tick bites. The activities considered to be the most at risk of exposure to tick bites are, in descending order: three occupational activities (forest monitoring activities, forestry and wood industry activities and scientific and/or analytical activities), five recreational activities and one hunting activity (mushroom picking, spending the night in the forest, hunting, naturalist activities, orienteering, and berry or fruit picking). Conclusions and significance: Prevention messages regarding tick bites could be targeted at people who engage in activities considered in this analysis to be at highest risk of exposure to tick bites.

Following the normalization of the COVID-19 pandemic, the focus of wastewater-based epidemiology (WBE) must be broadened from SARS-CoV-2 to encompass surveillance of other major infectious diseases, particularly for pathogens where conventional clinical monitoring systems exhibit inherent surveillance gaps. In this study, we conducted a continuous two-year WBE study (January 2023 to December 2024) across three high-population-density cities in Guangdong, China to establish epidemiological baselines for enteric diarrheal viruses. We analyzed monthly raw wastewater samples from major treatment plants using advanced molecular methods, including digital PCR (ddPCR) for viral load quantification and targeted high-throughput sequencing (tNGS) for genotypic analysis. Our findings revealed diverse circulation patterns among the monitored enteric viruses. Astrovirus (AstV) had the highest detection rate (100%), reflecting its broad endemic distribution, while Norovirus genogroup II (NoV GII) exhibited relatively high viral loads (median 4 × 10⁴ copies/mL) and presented explosive seasonal peaks (significant upward trend in spring.), highlighting its epidemic potential. Furthermore, distinct spatiotemporal patterns were observed, with Sapovirus showing a significant summer peak in Foshan city, contrasting with the winter/spring peaks in the other cities. The tNGS results demonstrated similar sensitivity to RT-PCR in virus detection, and sequencing analyses uncovered the co-circulation and periodic shifts in dominant viral genotypes, such as the emergence of multiple NoV and AstV lineages. This longitudinal WBE surveillance successfully established critical baseline data and demonstrated significant regional heterogeneity in viral circulation, providing essential, complementary data to inform public health strategies for preventing diarrheal outbreaks in urban settings.

Clade I mpox virus (MPXV) is endemic in the Democratic Republic of the Congo (DRC). Recent studies have described the changing epidemiology of mpox in the country, which has been mainly characterized by the emergence of new MPXV lineages, Clade Ib/sh2023 and Ia/sh2024, associated with sustained human-to-human transmission. Both Clade Ib/sh2023 and Ia/sh2024 are co-circulating in Kinshasa, the capital city of the DRC. Here, we report the first two cases of Clade IIb/sh2017 identified in Kinshasa, DRC, imported from West Africa and locally transmitted. Clinical specimens were collected and tested by PCR. We performed whole genome sequencing using a tiled-amplicon sequencing approach with Clade IIb MPXV-specific primers. The phylogenetic tree shows that Kinshasa Clade IIb MPXV is assigned to Clade IIb/sh2017 within the newly designated lineage G.1, as identified in January 2025 in Sierra-Leone.

Influenza A virus (IAV) continues to present a threat to public health, highlighting the need for safe and multi-target antivirals. In this study, anti-influenza activity, airborne transmission blocking capacity, and immunomodulatory effects of Cnidium monnieri polysaccharides (CMP) were evaluated. Cytotoxicity in A549 cells was assessed by CCK-8 (CC₅₀ = 8.49 mg/mL), antiviral efficacy against A/California/04/2009 (CA04) by dose-response (EC₅₀ = 1.63 mg/mL), and the stage of action by time-of-addition assays (pre-, co-, post-treatment). A guinea pig model infected with CA04 was used for testing the effect of pre-exposure CMP on transmission, with readouts including nasal-wash titers, seroconversion, lung index, and tissue titers (EID₅₀). RT-qPCR was employed to quantify the mRNA expression levels of proinflammatory cytokines, including TNF-α, IL-1β, and IL-6, in lung tissue, while Western blot analysis was performed to assess the expression and phosphorylation status of key proteins involved in the NF-κB signaling pathway. CMP suppressed viral replication in vitro within non-cytotoxic ranges, and pre-treatment-rather than co- or post-treatment-significantly reduced titers and cytopathic effect, consistent with effects at pre-entry steps and/or host priming. In vivo, pre-exposure CMP lowered nasal shedding, reduced aerosol transmission (3/6 seroconverted vs. 6/6 controls), decreased lung indices, and diminished tissue viral loads; IAV was undetectable in trachea at 7 days post-infection in pre-exposed animals, and nasal-turbinate titers declined relative to infection controls. Moreover, during in vivo treatment in mice, CMP significantly suppressed the levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) in lung tissue. This effect was mechanistically associated with CMP-mediated regulation of the NF-κB signaling pathway, leading to attenuation of inflammatory responses. These data indicate that CMP combines a favorable in vitro safety and efficacy profile with inhibition of airborne spread in vivo, supporting further mechanistic, pharmacokinetic, and fractionation studies toward translational development.

Norovirus (NoV) and sapovirus (SaV) are major viral pathogens causing acute gastroenteritis (AGE) in both children and adults in developed countries and are also responsible for large-scale outbreaks. However, in Quebec, Canada, there are limited and updated data with respect to the genotypes circulating and implicated in outbreaks, particularly for SaV. This study aimed to investigate the genetic diversity and genotype predominance of NoVs and SaVs associated with AGE outbreaks in Quebec, Canada. Confirmed NoV and SaV outbreaks from long-term care facilities and hospital settings between September 2011 and April 2016 were investigated (n = 252). NoVs and SaVs were genetically diverse: 21 RdRp-capsid combinations were identified, of which 10 are recombinants. NoV GII.4 New Orleans[P4 NewOrleans] was the predominant genotype from 2011 to 2013, and GII.4 Sydney[P31] was the predominant genotype from 2013 to 2015. In 2015-2016, no single genotype predominated; instead, GII.17[P17], GII.4 Sydney[P16], GII.4 Sydney[P31], and SaV GI.2 strains were co-circulating at similar frequencies. Notably, emerging global genotypes including GII.17[P17], GII.4 Sydney[P16], GII.2[P16], and GII.4 San Francisco[P31] were detected for the first time in Quebec. These findings may contribute to an enhanced understanding of NoV and SaV infection and spread, and to the development of candidate vaccines.

One highly consequential presentation of Venezuelan equine encephalitis virus (VEEV) infection is encephalitis. Here we considered anti-inflammatory interventions to limit the effects of this using a BALB/c subcutaneously challenged mouse model of disease. This disease model nearly ubiquitously presents with severe encephalitis, where viral neuroinvasion correlates with much of the outward clinical signs of disease. A selection of already licenced, commonly used anti-inflammatory drugs were tested in mice developing encephalitis (starting treatment at 24 h post challenge). Drug regimens were used that had previously been shown to have pharmacodynamic effects in mice for unrelated conditions. None of the treatment regimens tested reduced brain inflammation. A single anti-inflammatory drug (dexamethasone) was further tested utilising ascending doses in an effort to provide an effective anti-inflammatory regimen. Higher doses of dexamethasone (20 and 50 mg/kg) reduced inflammatory markers in the brain and lowered weight loss and clinical signs early on during infection. However, the 50 mg/kg regimen also caused the disease to become more severe at later time points when compared to controls. When combined with the antiviral drug molnupiravir, the negative effects of the dexamethasone treatment (20 and 50 mg/kg) were absent, and the positive disease severity-reducing effects remained. When combined with a specific VEEV monoclonal antibody (1A3B7), dexamethasone significantly reduced the antibody's protective effects. These data present currently unique insights into how anti-inflammatory approaches might benefit patients with VEEV disease and where caution might be advised.

Cassava (Manihot esculenta) is a staple crop in sub-Saharan Africa threatened by several viral diseases. Here, we describe the genome sequence of a novel bipartite cheravirus (family Secoviridae) infecting cassava in the Democratic Republic of Congo and Tanzania. We designate the new virus "cassava Congo cheravirus". Each RNA segment encodes a single polyprotein (P1 and P2 for RNA1 and RNA2, respectively), embedded with various putative cleavage sites (six and three in P1 and P2, respectively), consistent with members of the genus Cheravirus. We note two new features in the P1: (i) the presence of two domains, X1 and X2, upstream of the putative helicase region, which we also predict in other cheraviruses and (ii) the presence of a Maf/HAM1-like inosine triphosphatase (ITPase) domain, a rare motif among viruses only previously detected in three potyviruses and a torradovirus, all of which infect plants from the Euphorbia family. Phylogenetic analyses placed the virus firmly within the genus Cheravirus, with amino acid identities in the Pro-Pol and coat protein regions well below existing ICTV species thresholds, supporting its classification as a virus belonging to a new species in the Cheravirus genus. Spatially distinct isolates from Bas-Congo, South-Kivu, and Tanzania form three genetic clusters, with evidence of recombination in both RNA segments. These results expand the known diversity of cassava viruses and suggest possible adaptation to the cassava host via ITPase acquisition.

Infection with Hepatitis E Virus (HEV) is often asymptomatic but can also lead to chronic infection in immunosuppressed individuals. Although fecal-oral transmission of HEV is well established, transmission by blood transfusion has also been reported. Here, we studied HEV seroprevalence in a cohort of 1000 blood donors (50% male, age 18-73 years, mean 35 years) at the University Medical Center Hamburg-Eppendorf in Germany. We found a seroprevalence of anti-HEV IgG of 16.6%. Interestingly, 1.3% of the blood donors had positive IgM serology despite testing negative for HEV by polymerase chain reaction (PCR). Analysis of preceding and follow-up samples showed persistence of IgM antibodies for up to seven months in asymptomatic individuals. In eight individuals, anti-HEV IgM positivity persisted for 0 to 7 months (median 2 months), as confirmed by testing stored samples. This study demonstrates that anti-HEV IgM positivity can persist for more than six months in individuals who had neither clinically overt hepatitis E nor a viremia duration that would allow PCR positivity to be detected.

Ten years have passed since the onset of the Zika virus (ZIKV) epidemic in Brazil, which began in 2015 and rapidly evolved into a global public health emergency [...].

Biocontainment laboratories often have limited access to a range of instruments required for conducting standard assays on infected materials. Consequently, some of the protocols involving infected samples are conducted outside a biocontainment facility. To be compliant with regulatory requirements and minimize health and safety risks for scientific personnel, it is imperative to test procedures rigorously for safely removing infected samples from biocontainment areas. This study validated the chemical inactivation of Nipah virus (NiV), a representative member of the Henipavirus genus, in animal tissues and serum. Importantly, this work demonstrated successful NiV-spiking of non-human primate (NHP) tissues and their subsequent inactivation. This is important because NHP tissues contain unpredictable amounts of infectious virus. The primary objective was to establish standardized protocols that are compliant with regulations to permit safe retrieval of infected biological samples with high NiV infectious virus content from ABSL-4 laboratories for subsequent downstream processing under lower biocontainment conditions.