Journal of Medical Virology最新文献

Influenza D virus (IDV) was first isolated in 2011 from a swine with respiratory disease symptoms in the United States. Epidemiological and serological evidence suggests that cattle are the natural reservoir of IDV, with periodic spillover events to other animal hosts. This study investigated the seroprevalence of two IDV lineages, D/660 and D/OK, among cattle workers in Southern Italy between 2023 and 2024 to better characterize the zoonotic exposure risk in this occupational setting. A control group from the same geographical area was also included. Serum samples were tested by hemagglutination inhibition and virus neutralization (VN) assays. Overall, 42.9% (60/140) of cattle workers were positive at least to one of the two IDV lineages. Moreover, 39.3% (55/140) were positive for D/660 and 34.3% (48/140) for D/OK, with all but one positive result confirmed by VN assay. In the control group, tested only for D/660, a significantly higher seroprevalence was observed, with 65.0% (39/60) testing positive. These findings suggest that IDV exposure is not restricted to occupational settings involving direct contact with cattle and underscore the importance of incorporating IDV into current influenza surveillance programs.

Since 1998, enterovirus A71 (EV-A71) has caused several outbreaks in Taiwan with hundreds of severe cases and deaths. EV-A71 exhibits a high genome mutation rate, resulting in a diverse viral population, called quasispecies. However, the consequence of variations found in quasispecies with EV-A71 viral virulence remains elusive. In this study, we aim to analyze the viral genomes of severe and mild clinical isolates from 2012 EV-A71 outbreak. Clinical isolates underwent isolation, extraction, and amplification, then sent for next-generation sequencing (NGS) using Illumina MiSeq. Using bioinformatics tools, sequence variation analysis identified four distinct, statistical variations, located in the 5′-UTR, 2C, 3A, and 3D of EV-A71 isolates between severe and mild clinical cases. Two variants found in the 3A and 3D polymerase (3Dpol) region, respectively, were found to have higher proportions in severe cases. The 3Dpol variant protein showed reduced polymerase activity compared to wild-type polymerase. In contrast, the 3A mutant virus shows a higher replication rate and greater fitness in both RD and DLD-1 cells. With better growth rates and fitness, the EV-A71 3A-5286C (76S) variation has a greater ability to maintain the fast-replicating populations and may be correlated with the disease severity and virulence of EV-A71.

Kyasanur Forest Disease (KFD), commonly known as ‘monkey fever,’ is a highly neglected tropical disease caused by the Kyasanur Forest Disease Virus (KFDV). KFD is endemic to the Western Ghats of Karnataka, India, with seasonal outbreaks during December to June every year. As there is no standard treatment regime, KFD can be fatal with a mortality rate of 2%–10%. Currently, KFD is detected through a non-specific IgM-ELISA followed by RT-PCR, which often delays diagnosis, leading to increased disease severity and even death. To address this, we focused on developing a specific antigen-based KFD detection. The KFDV Envelope Domain III (EDIII) and Non-Structural 1 (NS1) proteins were chosen as detection markers, cloned, and expressed using pET28a(+) vector in BL-21 (Rosetta) E. coli and purified. These proteins were used to raise polyclonal antibodies in rabbits and the antibody titre was found to be 1:256 000 and 1:512 000 against rEDIII and rNS1 proteins, respectively. Importantly, these polyclonal antibodies showed no cross-reactivity against corresponding dengue virus EDIII and NS1 proteins. Using polyclonal antibodies against rEDIII, we developed sandwich ELISA for the specific detection of KFD, which has demonstrated high specificity and sensitivity. Further, anti-rEDIII polyclonal antibodies also detected full-length KFDV-E protein expressed in mammalian cells, confirming the antibody specificity for the native viral antigen.

SARS-CoV-2, like other positive-sense RNA viruses, manipulates host lipid metabolism to facilitate its replication by enhancing lipogenesis and lipid droplet formation. This infection disrupts bioactive lipid levels associated with the inflammatory response by increasing nuclear factor-κB (NF-κB) transcription. Recent findings have shown that NF-κB activation is essential for sustaining SARS-CoV-2 replication. Therefore, we proposed that counteracting NF-κB–driven pro-inflammatory lipid production could be accomplished by enhancing an anti-inflammatory, lipolytic pathway. Our goal was to increase levels of Palmitoylethanolamide (PEA), the main activator of the Peroxisome Proliferator-Activated Receptor-α (PPAR-α), a transcription factor that suppresses lipogenesis and NF-κB transcription. PEA levels are mainly regulated by N-acylethanolamine acid amidase (NAAA), a lysosomal enzyme that breaks down PEA. We hypothesized that inhibiting NAAA might interfere with SARS-CoV-2 replication by allowing PEA to accumulate, thereby activating PPAR-α and suppressing NF-κB. Our results show that genetic or chemical ablation of NAAA significantly suppresses SARS-CoV-2 replication ex-vivo by 3 log₁₀ in human-derived precision-cut lung slices. We investigated whether inhibiting NAAA could block NF-κB activation by steering its opposite PPAR-α mediated pathway. We observed increased PPAR-α expression in NAAA KO cells, while PPAR-α expression remained low in infected untreated cells. Elevated PPAR-α expression correlated with reduced NF-κB activation when NAAA is ablated. These findings highlight NAAA as an essential host factor for SARS-CoV-2 replication and propose a mechanism that reduces both replication and inflammation by targeting NF-κB during Coronaviridae replication.

Epstein-Barr virus (EBV) acquired in childhood is asymptomatic, with the tonsils as the entry site to infect B lymphocytes and establish latency. Little is known about whether the microbiota influences EBV persistent infection. We aimed to characterize the tonsil microbiome with different EBV latency types. A cohort of 60 children with tonsillar hyperplasia were included. EBV latency types (0/I/II/III) and lytic phase were determined by immunohistochemistry. 16S NGS of lymphoid tonsillar tissue was carried out with the Illumina platform. Bioinformatic analysis was carried out with QIIME2 2023.2 software and the R studio packages Phyloseq and DESeq 2. Absolute quantification of Fusobacterium nucleatum and its subspecies was conducted using qPCR. A minor α-diversity was observed in the latency III group (p < 0.0014). Therefore, the reference employed for differential abundance analysis was the latency III group. Latency III group was characterized by Fusobacterium when compared with non-infected (LFC = 43.81, p = 2.03E-10), latency 0 (LFC = 23.20, p = 2.16E-05); latency I (LFC = 23.21, p = 1.36E-07), and latency II (LFC = 38.03, p = 7.36E-19). In contrast, Prevotella histicola was decreased (LFC = −26.06, p = 0.0004). Latency group III with lytic phase was characterized by Fusobacterium (LFC = 26.74, p = 5.30E-05). Fusobacterium nucleatum subspecies vicentii had a higher copy number within latency group III (p = 0.020). We found that a microbiome signature in lymphoid tonsillar tissue is related to EBV infection, where Fusobacterium nucleatum subspecies could play a crucial role in latency III and the lytic phase of EBV. This study provides the first evidence that the tonsil microbiome varies with EBV stages, a finding relevant to EBV-associated diseases.

Noroviruses are a major cause of acute gastroenteritis worldwide. In Beijing, norovirus GII.17 outbreaks, which dominated in 2014–2015 (66.7%), surged again from 1.3%–12.2% (2015–2024) to 81.7% (2024–2025), with reported outbreaks during July 2024–February 2025 dramatically exceeding the prior year (301 vs. 103). From 2014 to 2025, 249 GII.17 outbreaks were identified, comprising 107 Kawasaki308 (1525 cases) and 142 Romania-2021 (1840 cases) based on phylogenetic analysis. The proportion of outbreak settings differed for Romania-2021 and Kawasaki308: kindergartens (35.2% vs. 37.4%), primary schools (46.5% vs. 29.0%), middle schools (5.6% vs. 12.1%) and others (12.7% vs. 21.5%). Romania-2021 cases were younger and had more vomiting than Kawasaki308 cases. Phylogenetic analysis revealed that novel GII.17 strains dominated in Beijing in 2024–2025 clustered with contemporaneous global strains, forming a distinct subcluster (New_2023–2025) within New (Romania-2021 like) cluster. This subcluster exhibited unique amino acid substitutions in VP1, VP2 and non-structure proteins compared to other clusters and New subclusters. Our findings confirm the dominance of Romania-2021 like strains during 2024–2025 in Beijing. Differences in symptom profiles and affected age groups between Kawasaki308 and Romania-2021, and unique amino acid substitutions may help explain the rapid predominance of the emerging cluster.