Search Results (313)

Human viral entry receptor mouse models exist to overcome a fundamental experimental barrier: many clinically important viruses bind their human entry factors far more efficiently than the corresponding murine orthologs, leaving conventional mice unable to support authentic infection, physiological tissue tropism, or meaningful countermeasure evaluation. This review is organized around the receptor-humanization concept rather than around a single coronavirus model. Engineering strategies compared here include random transgenesis, endogenous-locus knock-in, minimal receptor-interface humanization, conditional and inducible expression, and transient vector-mediated delivery. Receptor systems covered span human angiotensin-converting enzyme 2 (hACE2)-dependent sarbecoviruses, human dipeptidyl peptidase 4 (hDPP4)-dependent Middle East respiratory syndrome coronavirus (MERS-CoV), human cluster of differentiation 4/human C-C chemokine receptor type 5 (hCD4/hCCR5)-dependentt human immunodeficiency virus type 1 (HIV-1), adenovirus receptor models, human intercellular adhesion molecule 1 (hICAM-1) rhinovirus systems, hepatitis C virus (HCV), hepatitis B virus (HBV), and hepatitis D virus (HDV) entry-factor models, measles receptor models, poliovirus receptor/CD155 (PVR/CD155) models, human scavenger receptor class B member 2 (hSCARB2) enterovirus systems, and human transferrin receptor 1 (hTfR1) arenavirus models. We then discuss how these platforms support antibody evaluation, Fc-effector analysis, vaccine protection, variant benchmarking, and safety assessment. These models yield the most reliable data when the experimental question is explicitly entry-dependent and when receptor expression level, anatomical distribution, pathology window, and immune context have all been independently validated. They are least informative when receptor expression is non-physiological, when disease readouts are driven by promoter artifacts, or when post-entry species barriers remain the dominant bottleneck. A validation-centered framework is therefore proposed to guide the selection of each model for the specific antiviral antibody or vaccine question it can legitimately answer. Full article

The Middle East Respiratory Syndrome coronavirus (MERS-CoV) remains a significant global health concern due to the absence of approved antiviral therapeutics. In this study, we developed a ligand-based machine learning framework to identify potential inhibitors of the MERS-CoV main protease (Mpro) using molecular representations derived from SMILES strings. Multiple classification algorithms, including logistic regression, support vector machines, random forests, and Extreme Gradient Boosting (XGBoost), were systematically evaluated. Model performance was assessed through both internal validation and an external dataset. While several models exhibited strong performance during validation, the Random Forest classifier demonstrated the most robust and consistent generalization, achieving superior predictive performance on the external dataset. To ensure model reliability, a comprehensive validation strategy was implemented, including strict data partitioning to prevent structural overlap, Y-scrambling analysis to eliminate chance correlations, and applicability domain assessment to define the model’s reliable prediction space. The final model was deployed as an interactive web-based application, enabling rapid virtual screening of compounds through single or batch SMILES input, and providing activity predictions along with probability scores and selected physicochemical descriptors. Overall, this study presents a reproducible ligand-based approach for supporting the early-stage identification of potential MERS-CoV Mpro inhibitors. Full article

In 2024 Kenya had a population of 4.78 million camels that contributed to the livelihoods of pastoralist communities in northern Kenya. Previous studies in Kenya, Saudi Arabia and eastern Africa demonstrated high seroprevalence of Middle East respiratory syndrome coronavirus (MERS-CoV)-specific antibodies in dromedary camels, as well as sporadic transmission of MERS-CoV from camels to humans. Based on the MERS-CoV data and the very close contact between owners and their camels in northern Kenya, we speculated that camels may also transmit other zoonotic viruses, such as Rift Valley fever virus (RVFV). In this study, 493 camel and 197 human sera were collected in Marsabit, Kenya, through a cross-sectional survey in 2018 and analyzed for the presence of RVFV IgG antibodies using a laboratory-developed indirect enzyme-linked immunosorbent assay (ELISA). Overall, 15.6% of camels and 7.6% of humans were RVFV IgG-positive; IgG-positive camels were predominantly females in large population herds and IgG-positive humans were engaged in farming-related activities and were greater than 18 years old. Of the eight location groups sampled, two had high camel (site 2 and site 6) and two had high human (site 5 and site 6) RVFV seropositivity rates. These data suggest that camelids, such as dromedary camels, may serve as amplifying hosts for vector-borne zoonotic diseases, such as RVFV, and that humans with frequent farming and camel meat, milk, or camel product contact may have increased risk for RVFV exposure or infection. Full article

Background/Objectives: Coronaviruses are a family of positive-sense RNA viruses that cause respiratory and gastrointestinal disease in mammals and birds. Their zoonotic nature and high mutability make them a pandemic threat. UNICOR-v is a pre-pandemic, pan-coronavirus vaccine composed of an adjuvanted mix of twelve synthetic peptides originating from conserved regions within Nsp12 and M coronavirus proteins containing clusters of predicted T-cell epitopes. Here, we evaluate the immunogenicity of UNICOR-v and its efficacy against Middle East Respiratory Syndrome-related coronavirus (MERS). Methods: Animals were vaccinated with an adjuvanted equimolar mix of UNICOR-v. Humoral and cellular immunogenicity were assessed 28 days later through ELISA and FLUOROSpot. Vaccine efficacy was assessed in a DPP4 knock-in (HDPP4-KI) mouse model where mice were challenged post-vaccination with a lethal or non-lethal dose of MERS-CoV-MA. Results: Vaccination with UNICOR-v induced high IgG titers in both mice and rabbits and cellular secretion of pro-inflammatory cytokines. Vaccination with UNICOR-v, or passive serum transfer, significantly reduced viral lung titers 4 days post-infection compared to placebo. Vaccination induced lower immune cell infiltration in the alveolar space and increased repair of the cells lining the major airways in vaccinated mice, translating to increased survival rate compared to placebo. Conclusions: These data demonstrate the ability of conserved T-cell epitopes to protect against MERS-CoV infection, supporting further characterization of the breadth of protection of UNICOR-v against other coronaviruses that affect humans and livestock, following a One Health approach to control this highly zoonotic family of viruses. Full article

In this study, the phenotypic consequences of naturally occurring single nucleotide polymorphisms (SNPs) in the Middle East respiratory syndrome coronavirus (MERS-CoV) Spike protein were investigated. The impact of Spike mutations on the syncytia formation and neutralisation of contemporary MERS-CoV strains is not currently well understood. Mutations were identified by aligning 584 MERS-CoV Spike sequences from either human clinical isolates collected between 2012 and 2024 or from a clinical isolate that had been passaged in human cells. Fifteen SNPs of interest occurring in the N-terminal domain (NTD), receptor binding domain (RBD) and adjacent to the S1/S2 cleavage site were selected for further characterisation based on their location in the Spike protein, frequency and identification in previous studies. A contemporary clade B, lineage 5 wildtype Spike sequence, obtained from a human MERS-CoV clinical isolate, was used as the backbone in this study. The mutations of interest were introduced to the wildtype backbone to generate Spike variants. Spike variants were characterised via cell–cell fusion assays, and a lentiviral pseudotyping system was used to investigate the impact of these Spike mutations on neutralisation. The I529T, E536K and L745F mutations were shown to increase fusion and syncytia formation. The L411F, T424I, L506F, L745F and T746K mutations were found to increase resistance to neutralisation by pooled patient sera. This study has identified novel naturally occurring Spike mutations that resulted in phenotypic differences in the syncytia formation and neutralisation of contemporary MERS-CoV strains. Continued investigation of the phenotypic consequences of MERS-CoV Spike mutations is essential for assessing the risk to public health, especially given the pandemic potential of this virus. Full article

The MERS-CoV (Middle East respiratory syndrome coronavirus) is a zoonotic virus with a high mortality rate and a lack of antiviral drugs, underscoring the need for effective therapeutic methods. Viral entry depends on interactions between viral surface proteins and human receptors, with Dipeptidyl Peptidase-4 (DPP4), a transmembrane glycoprotein, acting as the receptor for MERS-CoV. We employed Molecular Dynamics (MD) Simulations to identify critical interface residues under a high-performance computing (HPC) workflow for accelerated results. Target residue pairs were identified through analysis of salt bridge and hydrogen bond occupancy. The stability of these residues was confirmed through three independent MD Simulations at human body temperature and constant pressure. Additionally, binding affinity predictions were calculated to determine the interaction strength between the virus and human receptors. Applying the scientific threshold criteria, we narrowed our results to seven key interaction pairs; two of the identified pairs (Asp510-Arg317, and Arg511-Asp393) are consistent with findings published in previous research studies, and five novel interactions are proposed for future experimental studies with our active collaborators in Pharmacology. The results provide a molecular basis for targeted mutation-based experiments and support the rational design of structure-based inhibitors aimed at disrupting the MERS-CoV-DPP4 complex, thereby facilitating the translation of computational findings into antiviral drug discovery. Full article

RNA viruses pose a persistent global threat due to their high mutation rates, zoonotic potential, and rapid adaptability. Emergence events have risen steadily, as demonstrated by major outbreaks caused by Influenza A, Ebola, Zika, and Chikungunya viruses, followed by the coronavirus epidemics of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV-1) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and culminating in the COVID-19 pandemic. These characteristics frequently compromise the durability of existing vaccines and antiviral therapies, highlighting the urgent need for new antiviral agents. Alkaloids, a structurally diverse class of nitrogen-containing natural compounds, have gained attention for their ability to interfere with multiple stages of the viral life cycle, including entry, replication, protein synthesis, and host immune modulation. To our knowledge, this review compiles all currently reported alkaloids with antiviral activity against RNA viruses and summarizes their proposed mechanisms of action, distinguishing evidence from in vitro, in vivo, and in silico studies. Quaternary alkaloids are discussed separately because their permanent ionic charge enables distinctive interactions with membranes and host pathways. Although many findings are promising, clinical translation remains limited by incomplete mechanistic validation, scarce in vivo data, suboptimal bioavailability, narrow therapeutic windows, and inconsistent experimental methodologies. To advance the field, future research should prioritize RT-qPCR–based antiviral evaluation to accurately quantify viral replication, incorporate mechanistic assays to clarify modes of action, apply structure–activity relationship (SAR) approaches for rational optimization, and expand in vivo pharmacokinetic and efficacy studies to assess therapeutic feasibility. Overall, alkaloids represent a promising yet underdeveloped reservoir for next-generation antiviral discovery against rapidly evolving RNA viruses. Full article

Pathogenic Middle East respiratory syndrome CoV (MERS-CoV), first identified in Saudi Arabia in 2012, continues to pose a threat to public health. The trimeric spike (S) protein of MERS-CoV binds to the cellular receptor through the receptor-binding domain (RBD) in the S1 subunit to initiate virus entry and infection. Therefore, both the S protein and its RBD are targets for the development of MERS-CoV vaccines. Nevertheless, a direct comparison of the immune efficiency of S- and RBD-based MERS-CoV vaccines has not been made. Here, we compared two mRNA vaccines, respectively, targeting the S (S-mRNA) and RBD (RBD-mRNA) of MERS-CoV for their durable immunogenicity, neutralizing activity, and protective efficacy in a mouse model. Both mRNAs encapsulated with lipid nanoparticles (LNPs) maintained strong stability at various temperatures during the detection period. LNP-encapsulated RBD-mRNA elicited significantly higher and more durable antibodies than LNP-encapsulated S-mRNA, maintaining stronger and broadly neutralizing activity against the MERS-CoV original strain, as well as multiple variants containing key mutations within the RBD region. Importantly, RBD-mRNA provided durable protective efficacy against MERS-CoV infection in middle-aged mice, and this protection was associated positively with serum neutralizing antibody titers. Overall, this study identifies RBD-mRNA as an effective vaccine against MERS-CoV, with great potential for further development. Full article

The Middle East Respiratory Syndrome coronavirus (MERS-CoV) remains a highly significant threat to global public health. Dromedary camels are the zoonotic source of human infection. All cases of zoonotic Middle East Respiratory Syndrome (MERS) have occurred in Middle Eastern countries despite MERS-CoV infection of camels being widespread in Africa. This disparity in the geographic burden of the disease may be due to genomic differences between MERS-CoV circulating in Middle Eastern countries (clades A and B) versus those infecting camels in Africa (clade C), although the precise genetic determinants of virulence remain to be elucidated. The objective of the studies reported here was to evaluate differences in the magnitude of virus shedding and in transmissibility of clades A/B and C viruses using alpacas as a surrogate for dromedary camels. We found that two of three African-origin, clade C strains of MERS-CoV induced very reduced levels of virus shedding and were transmitted inefficiently to contact control animals as compared to one other clade C virus and representative viruses from clade A and B. Lower virus titers in the nasopharynx may be associated with lower zoonotic transmission and human disease severity and may explain the observed epidemiology of MERS-CoV in Africa where zoonotic disease appears rare. These results add to our understanding of the transmission of different lineages of MERS CoV in camelids and zoonotic transmission. Full article

Merbecovirus, a subgenus of coronaviruses that includes the highly pathogenic Middle East respiratory syndrome coronavirus (MERSr-CoV), poses a significant zoonotic threat. To better understand its host adaptation and potential for cross-species transmission, we conducted a comprehensive analysis of codon usage patterns in 1967 Merbecovirus sequences. Phylogenetic analysis confirmed the division of Merbecoviruses into seven distinct clusters. Codon usage bias was found to be low and predominantly shaped by natural selection, with a consistent A/U-rich composition across the genome. Codon adaptation index (CAI) and relative codon deoptimization index (RCDI) analyses indicate that Merbecovirus exhibits potential host adaptation to Sus scrofa (pigs), Equus caballus (horses), and Oryctolagus cuniculus (rabbits), suggesting a risk of cross-species transmission. Strikingly, this genomic-level adaptation prediction is supported by emerging functional evidence: recent studies have demonstrated that key Merbecovirus lineages utilize diverse cell entry receptors (DPP4 or ACE2), a fundamental determinant of host tropism. For instance, the ability of the HKU5 lineage to utilize ACE2 receptors from mustelids like minks (Neogale vison) provides mechanistic support for the host adaptability trends inferred from our genomic analyses. By integrating existing receptor specificity data, this study provides the first systematic, large-scale analysis of codon usage across the Merbecovirus subgenus, elucidating key mechanisms of genomic adaptation and viral evolution. Our analytical framework provides a novel comparative perspective on host diversity and pinpoints specific surveillance priorities for mitigating future spillover risks. Full article

With the popularization of social media, information related to public health events has seen explosive growth online, making it essential to accurately identify informative tweets with decision-making and management value for public health emergency response and risk monitoring. However, existing methods often suffer performance degradation during cross-event transfer due to differences in data distribution, and research specifically targeting public health events remains limited. To address this, we propose the Label Confusion Domain Adversarial Network (LCDAN), which innovatively integrates label confusion with domain adaptation to enhance the detection of informative tweets across different public health events. First, LCDAN employs an adversarial domain adaptation model to learn cross-domain feature representation. Second, it dynamically evaluates the importance of different source domain samples to the target domain through label confusion to optimize the migration effect. Experiments were conducted on datasets related to COVID-19, Ebola disease, and Middle East Respiratory Syndrome public health events. The results demonstrate that LCDAN significantly outperforms existing methods across all tasks. This research provides an effective tool for information detection during public health emergencies, with substantial theoretical and practical implications. Full article

At least three betacoronaviruses have spilled over from bats to humans and caused severe diseases, highlighting the threat of zoonotic transmission. Thus, it is important to enhance surveillance capabilities by developing tools capable of detecting a broad spectrum of bat-borne betacoronaviruses. Three monoclonal antibodies (mAbs) targeting the nucleocapsid (N) protein were generated using recombinant N proteins from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV). The cross-reactivities of these mAbs were evaluated against a panel of betacoronaviruses. Sandwich ELISAs (sELISAs) were subsequently developed to detect bat-borne betacoronaviruses that have high zoonotic potential. Among the mAbs, 7A7 demonstrated the broadest cross-reactivity, recognizing betacoronaviruses from the Sarbecovirus, Merbecovirus and Hibecovirus subgenera. The first sELISA, based on mAbs 7A7 and 6G10, successfully detected N protein in all clinical swab samples from COVID-19 patients with cycle threshold (Ct) values < 25, achieving 75% positivity overall (12/16). Using this as a reference, a second sELISA was established by pairing mAb 7A7 with mAb 8E2, which binds to multiple merbecoviruses. This assay detected the N protein of two merbecoviruses, namely the human MERS-CoV and bat-borne HKU5-CoV, at high sensitivity and has a limit of detection (LOD) that is comparable to the first sELISA used successfully to detect COVID-19 infection. These broadly reactive mAbs could be further developed into rapid antigen detection kits for surveillance in high-risk populations with close contact with wild bats to facilitate the early detection of potential zoonotic spillover events. Full article

Background: To provide clues and a diagnostic basis for patients with fever of unknown origin through urinary proteomics analysis. Methods: For the first time, an attempt was made to conduct a full-library search for viruses in urine samples. Liquid chromatography–tandem mass spectrometry (LC-MS/MS) technology was employed to analyze the urinary proteomes of patients with fever of unknown origin, and to search for and identify viral protein fragments. In this study, there is no need to pre-determine the types of substances present in the samples. As long as the relevant sequences of viruses are available in the database, virus searches can be performed on the samples. Results: In the urine samples, multiple specific peptides from various viruses, such as the monkeypox virus, salivirus A, human herpesvirus 8 type P, Middle East respiratory syndrome-related coronavirus, rotavirus A, Orf virus (strain NZ2), human herpesvirus 2 (strain HG52), human adenovirus E serotype 4, influenza A virus, human coronavirus NL63, parainfluenza virus 5 (strain W3), Nipah virus, and hepatitis C virus genotype 2k (isolate VAT96), could be observed. It was found that the detection amounts of multiple viruses in febrile patients were much higher than those in the control group. Among them, the increase multiple of salivirus A was as high as more than 4200 times, and the increase multiples of multiple viral proteins were higher than 20 times. Conclusions: Viral fragments in urinary proteins can be reliably identified using mass spectrometry, which provides clues for the investigation of unexplained fever and may also be applied to the exploration of any unknown diseases. Full article

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging zoonotic pathogen with different pathogenesis in humans and camels. The mechanisms behind the higher tolerance of camels to MERS-CoV infection are still unknown. Monocytes are innate myeloid cells that are able, depending on the local stimulation in their microenvironment, to differentiate into different functional subtypes of macrophages with an impact on the adaptive immune response. Several in vitro protocols have been used to induce the differentiation of monocyte-derived macrophages (MDMs) in human and several veterinary species. Such protocols are not available for camel species. In the present study, monocytes were separated from camel blood and differentiated in vitro in the presence of different stimuli into MDM. Camel MDMs generated in the presence of a combined stimulation of monocytes with LPS and GM-CSF resulted in the development of an M1 macrophages phenotype with increased abundance of the antigen-presentation receptor MHCII molecules and a decreased expression of the scavenger receptor CD163. The expression pattern of the cell markers CD163, CD14, CD172a, CD44, and CD9 on MDM generated in the presence of the MERS-CoV S1 protein revealed similarity with M-CSF-induced MDM, suggesting the potential of the MERS-CoV S1 protein to induce an M2 macrophages phenotype. Similarly to the effect of M-CSF, MERS-CoV-S protein-induced MDMs showed enhanced phagocytosis activity compared to non-polarized or LPS/GM-CSF-polarized MDMs. Collectively, our study represents the first report on the in vitro generation of monocyte-derived macrophages (MDMs) in camels and the characterization of some phenotypic and functional properties of camel MDM under the effect of M1 and M2 polarizing stimuli. In addition, the results suggest a polarizing effect of the MERS-CoV S1 protein on camel MDMs, developing an M2-like phenotype with enhanced phagocytosis activity. To understand the clinical relevance of these in vitro findings on disease pathogenesis and camel immune response toward MERS-CoV infection, further studies are required. Full article

Human outbreaks of Middle East respiratory syndrome coronavirus (MERS-CoV) are more common in Middle Eastern and Asian human populations, associated with clades A and B. In Africa, where clade C is dominant in camels, human cases are minimal. We reviewed 16 studies (n = 6198) published across seven African countries between 2012 and 2024 to assess human MERS-CoV cases. We also analyzed data from four cohort studies conducted in camel-keeping communities between 2018 and 2024 involving camel keepers, camel slaughterhouse workers, and hospital patients with acute respiratory illness (ARI). The analysis showed a pooled MERS-CoV prevalence of 2.4% (IQR: 0.6, 11.4) from 16 publications and 1.14% from 4 cohort studies (n = 2353). Symptomatic cases were rarely reported, with most individuals reporting camel contact, and only 12% had travel history to the Middle East. There was one travel-associated reported death, resulting in a mortality rate of 0.013%. The findings suggest a low camel-to-human transmission of clade C MERS-CoV in Africa. Ongoing research focuses on genomic comparisons between clade C and the more virulent clades A and B, alongside the surveillance of viral evolution. This study highlights the need for continuous monitoring but indicates that MERS-CoV clade C currently poses a minimal public health threat in Africa. Full article