Search Results (300)

Research on highly pathogenic biosafety level 4 (BSL-4) viruses that are classified as Select Agents involves transferring inactivated materials to lower containment levels for further analysis. Compliance with Select Agent and BSL-4 safety regulations necessitates the validation and verification of inactivation procedures. To streamline this process, it would be beneficial to use surrogate BSL-2 viruses for inactivation studies. This not only simplifies BSL-4 work but also enables the testing and validation of inactivation procedures in research facilities that lack access to high-containment laboratories yet may receive samples containing highly pathogenic viruses that require efficient and complete inactivation. In this study, we used Hazara virus (HAZV) as a surrogate virus for Crimean–Congo hemorrhagic fever virus to show the efficacy of various inactivation methods. We demonstrate the successful inactivation of HAZV using TRIzol/TRIzol LS and aldehyde fixation. Importantly, the parameters of the aldehyde inactivation of cell pellets differed from those of the monolayers, highlighting the importance of inactivation validation. As part of this study, we also defined specific criteria that must be met by a BSL-2 virus to be used as a surrogate for a closely related BSL-4 virus. Defining these criteria helps identify suitable nonpathogenic surrogates for developing inactivation procedures for highly pathogenic viruses. Full article

Ultraviolet (UV) radiation can be used to inactivate microorganisms, with upper-room UV germicidal irradiation (UR-UVGI) representing a promising approach. This study investigated the inactivation of the airborne surrogate virus Phi6 by a UR-UVGI system based on light-emitting diodes (LEDs) in a realistic test setup. Two test scenarios were used, one with continuous Phi6 release, simulating a source located in the room and leading to a dynamic equilibrium, and the second simulating a situation in which the source has left the room and an exponential decay is evaluated. The “Incremental Evaluation Model” was adapted and used to evaluate the dynamic equilibrium measurement. At a position in the breathing direction 5 m away from the Phi6 source, the loss coefficient (air exchange rate) was 25 h⁻¹ in the first scenario and 30 h⁻¹ in the second. These results show that UR-UVGI systems can effectively inactivate microorganisms. However, at 1 m distance from the Phi6 source perpendicular to the breathing direction, only minimal inactivation was observed due to short-circuit airflow. At this position, the loss coefficient was <2 h⁻¹ in the first scenario and 17 h⁻¹ in the second scenario, indicating that short-circuit airflows can only be detected by dynamic equilibrium measurements. Full article

The objective of this study was to evaluate the time-course of incubation for the potential preventative mitigation of megaviruses using Termin-8 (a formaldehyde-based product) and Finio (non-formaldehyde solution) from Anitox. Emiliania huxleyi virus (EhV), an algal surrogate for African swine fever virus (ASFV), was treated with the recommended concentrations of Termin-8 (0.1% to 0.3%) and Finio (0.05% to 0.2%), and both viability qPCR (V-qPCR) and standard PCR (S-qPCR) were used to quantify EhV concentrations at 1 h, 5 h, 24 h and day 7 post-inoculation. Overall, Finio, and to a lesser extent Termin-8, at their highest treatment concentrations, showed the greatest log reduction of 4.5 and 2 log₁₀ units, respectively, at 1 h post-inoculation. Although Termin-8 efficacy did not improve with time, due to its fixing of viral particles and rendering them non-infectious, treatment with Finio showed 100% viable viral inactivation (>5 log₁₀ reduction units) at the lowest concentration after 7 days of exposure. Our results demonstrate that both Termin-8 and Finio can be used as effective chemical mitigants against megaviruses such as EhV and ASFV and can be used as effective preventive or mitigation strategies to prevent the transmission of ASFV by reducing particle viability in contaminated feed, although additional research is warranted. Full article

The production of hydroponic fresh produce presents unique food safety and intervention challenges. A systematic approach was used to map and characterize the evidence on hydroponic food safety. Quantitative data describing the effectiveness of intervention studies were extracted, synthesized, and assessed for quality. A search of electronic databases yielded 131 relevant papers related to hydroponic food safety. Thirty-two studies focusing on food safety interventions reported 53 different interventions using chemical (n = 39), physical (n = 10), multiple-hurdle (n = 2), and biological (n = 2) approaches. Human pathogen indicators and surrogates were most often studied (n = 19), while pathogenic strains like Salmonella spp. (n = 9), Shiga toxin-producing Escherichia coli (STEC) (n = 5), Listeria monocytogenes (n = 2), and viruses (Hepatitis A virus (HAV), n = 1; norovirus (NoV), n = 1) were studied less frequently. Of fourteen articles (43.8%) investigating pre-harvest interventions, most (42.9%) did not specify the hydroponic system type. Gaps remain in the available evidence regarding the efficacy of interventions for controlling human pathogens in near-commercial hydroponic systems. The quality assessment revealed a significant lack of detailed reporting on methods and outcomes, making it difficult to translate the findings into practical recommendations for the industry; therefore, this review provides recommendations for the scientific community to improve future research design and reporting in this field. Full article

An unprecedented outbreak of Oropouche virus (OROV) is occurring in the Americas, characterized by thousands of confirmed cases and a wide geographical spread, including areas outside the Amazon Basin. Little is known about this neglected arbovirus regarding its pathophysiological aspects and potentially different transmission modes. This study describes the clinical course of a man who returned from a trip to Cuba and presented to our hospital 4 days after the onset of febrile symptoms. The patient was diagnosed with Oropouche fever and was followed for 177 days after the onset of symptoms. We performed a longitudinal investigation of the samples collected from several body sites (whole blood, serum, urine, and semen) with the aim of providing further insights into OROV infection dynamics, using the detection of antigenomic RNA as a marker of active viral replication. Clinical samples that were longitudinally collected over the course of OROV infection showed consistently higher amounts of antigenomic RNA compared to genomic RNA, even after viral clearance from serum. Moreover, our case study showed the persistence of OROV RNA in serum of less than 15 days from the onset of symptoms, as compared to up to one month in urine, three months in semen, and four months in whole blood. Our study suggests that Oropouche virus may persist in an actively replicating state in different body sites for long periods of time, with important implications for transmission dynamics. Furthermore, our results provide a diagnostic indication, suggesting that serum is inferior to both urine and whole blood as preferred diagnostic samples. Further studies are needed to determine the pathogenetic implications of these findings, as they have been derived from a single case and must be confirmed using a larger number of cases. Full article

Viral hemorrhagic septicemia virus (VHSV) is a major pathogen in Paralichthys olivaceus (olive flounder) aquaculture, necessitating effective vaccines and evaluation methods. This study assessed immune responses following intraperitoneal administration of an inactivated VHSV vaccine and identified surrogate markers of vaccine efficacy. Fish were sampled weekly over 8 weeks. Antigen-specific antibody titers were measured by ELISA, and the expression of seven immune-related genes (CD4, CD8, CD28, IgM, Mx, IFN, and IL-1β) was analyzed in the spleen, kidney, liver, and gill by qPCR. The vaccinated group showed 84% relative survival, while unvaccinated fish experienced 100% mortality. Antibody titers peaked at 4 weeks post-vaccination, aligning with elevated IgM expression in the spleen and kidney. CD4 (kidney) and CD28 (spleen) expression strongly correlated with antibody titers (r = 0.854 and 0.796, respectively), whereas IL-1β, IFN, and Mx showed moderate associations in specific tissues. These findings indicate that CD4, CD28, and IgM may serve as molecular indicators of humoral immune responses specifically following inactivated VHSV vaccination in olive flounder (Paralichthys olivaceus). Combining gene expression profiling with antibody analysis offers a non-lethal, practical approach to evaluating vaccine efficacy in aquaculture. Full article

Community-based serosurveillance for emerging zoonotic viruses can provide a powerful and cost-effective measurement of cryptic spillovers. Betacoronaviruses, including SARS-CoV, SARS-CoV-2 and MERS-CoV, are known to infect bats and can cause severe respiratory illness in humans, yet remain under-surveyed in high-risk populations. This study aimed to determine the seroprevalence of betacoronaviruses in an occupational cohort in contact with bats before and after the emergence of SARS-CoV-2. Serum samples from pre- and post-COVID-19 pandemic were screened using antigen-based multiplex microsphere immunoassays (MMIAs) and a multiplex surrogate virus neutralization test (sVNT). Pre-pandemic samples showed no SARS-CoV-2 antibodies, while post-pandemic samples from vaccinated participants displayed binding and neutralizing antibodies against SARS-CoV-2 and a related bat CoV. Furthermore, one participant (1/237, 0.43%) had persistent antibodies against MERS-CoV in 2017, 2018 and 2021 but was seronegative in 2023, despite reporting no history of traveling abroad or severe pneumonia. The observed sustained antibody levels indicate a possible exposure to MERS-CoV or a MERS-CoV-like virus, although the etiology and clinical relevance of this finding remains unclear. Ongoing surveillance in high-risk populations remains crucial for understanding virus epidemiology and mitigating zoonotic transmission risk. Full article

Norovirus, a foodborne pathogen, causes a significant economic and health burden globally. Although detection methods exist, they are expensive and non-field deployable. A flow-based dielectrophoretic biosensor was designed for the detection of foodborne pathogenic viruses and was tested using bacteriophage MS2 as a norovirus surrogate. The flow-based MS2 sensor comprises a concentrator and a detector. The concentrator is an interdigitated electrode array designed to impart dielectrophoretic effects to manipulate viral particles toward the detector in a fluidic channel. The detector is made of a silver electrode conjugated with anti-MS2 IgG to allow for antibody–antigen biorecognition events and is supplied with the electrical current for the purpose of measurement. Serially diluted MS2 suspensions were continuously injected into the fluidic channel at 0.1 mL/min. A cyclic voltammogram indicated that current measurements from single-walled carbon nanotube (SWCNT)-coated electrodes increased compared to uncoated electrodes. Additionally, a drop in the current measurements after antibody immobilization and MS2 capture was observed with the developed electrodes. Antibody immobilization at the biorecognition site provided greater current changes with the antibody-MS2 complexes vs. the assays without antibodies. The electric field applied to the fluidic channel at 10 V_pp and 1 MHz contributed to an increase in current changes in response to MS2 bound on the detector and was dependent on the MS2 concentrations in the sample. The developed biosensor was able to detect MS2 with a sensitivity of 10² PFU/mL within 15 min. Overall, this work demonstrates a proof of concept for a rapid and field-deployable strategy to detect foodborne pathogens. Full article

Background/Objectives: Patients suffering from inflammatory bowel diseases (IBDs) undergoing treatment with anti-TNF antibodies mount a diminished humoral immune response to vaccination against SARS-CoV-2 compared to healthy controls. The characterization of variant-specific immune responses is particularly warranted among immunosuppressed patients, where reduced responses may necessitate further medical interventions. Methods: This pilot study investigated the humoral immune response of vaccinated IBD patients on anti-TNF medication and a comparable group of healthy individuals against the viral variants Alpha, Beta, Gamma, Delta, and Omicron BA.1 and BA.5. While total IgG antibodies targeting the receptor binding site of the spike protein of SARS-CoV-2 were quantified using a chemiluminescence microparticle immunoassay (CMIA), their potential neutralizing capacity was determined using commercial and variant-specific in-house surrogate virus neutralization tests (sVNTs) against a variant-specific in-house VSV-pseudotyped virus neutralization test (pVNT) as the gold standard. Results: Employing variant-specific assays recapitulated the immune escape functions of virus variants. Conspicuously, antibody reactivity against Alpha and Omicron BA.1 and BA.5 was strikingly poor in IBD patient sera post-initial vaccination compared to healthy individuals. A comparison of the diagnostic performance of assays with the pVNT revealed that identification of patients with inadequate humoral responses by CMIA and sVNT may require adjustments to cut-off values and end-point titration of sera. Following adaptation of cut-off values, patient sera exhibited reduced reactivity against all tested variants. The assay panel used substantiated the impact of anti-TNF therapy in IBD patients as to reduced strength, function, and breadth of the immune response to several SARS-CoV-2 variants. The immune response measured following the second vaccination was comparable to the antibody response observed in healthy individuals following the first vaccination. Conclusion: Variant-specific sVNTs and pVNTs have the potential to serve as valuable tools for evaluating the efficacy of adapted vaccines and to inform clinical interventions in the care of immunosuppressed patients. Anti-TNF-treated individuals with antibody levels below the optimized CMIA threshold should be considered for early booster vaccination and/or close immunological monitoring. Full article

Hantaviruses, including the Sin Nombre virus (SNV) and Andes virus (ANDV), are associated with severe global health risks, causing high mortality rates in hantavirus pulmonary syndrome (HPS) patients. Neutralizing antibodies are essential for virus clearance and survival, making neutralization assays critical for understanding immunity and evaluating therapeutic strategies. In this study, we developed a recombinant vesicular stomatitis virus (VSV)-based surrogate system expressing SNV and ANDV glycoproteins (GPCs), enabling neutralization studies under biosafety level 2 conditions. The neutralization titers obtained with the VSV-based system closely matched the findings from authentic hantavirus assays performed under biosafety level 3 conditions, confirming its potential as a useful tool for determining immune responses and advancing hantavirus research. Full article

Background: Behavioral, social, and physical characteristics are posited to distinguish the sexes, yet research on transcription-level sexual differences in the brain is limited. Here, we investigated sexually divergent brain transcriptomics in pre-pubertal cynomolgus macaques, a commonly used surrogate species to humans. Methods: A transcriptomic profile using RNA sequencing was generated for the temporal lobe, ventral midbrain, and cerebellum of three female and three male cynomolgus macaques previously treated with an adeno-associated virus vector mix. Statistical analyses to determine differentially expressed protein-coding genes in all three lobes were conducted using DeSeq2 with a false-discovery-rate-corrected p-value of 0.05. Results: We identified target genes in the temporal lobe, ventral midbrain, and cerebellum with functions in translation, immunity, behavior, and neurological disorders that exhibited statistically significant sexually divergent expression. Conclusions: We provide potential mechanistic insights into the epidemiological differences observed between the sexes with regard to mental health and infectious diseases, such as COVID-19. Our results provide pre-pubertal information on sexual differences in non-human primate brain transcriptomics and may provide insight into health disparities between the biological sexes in humans. Full article

Background: The triglyceride-glucose (TyG) index has emerged as a novel surrogate marker of insulin resistance, but its changes after hepatitis C virus (HCV) eradication remain unclear. This study aimed to evaluate changes in the TyG index following direct-acting antiviral (DAA) treatment. Methods: HCV-infected patients achieving sustained virological response 12 weeks post-treatment (SVR12) were prospectively enrolled from May 2015 to June 2023. Exclusion criteria included the following: (1) failure to achieve SVR12; (2) use of anti-diabetes or anti-hyperlipidemia medications; and (3) hepatitis B virus or human immunodeficiency virus co-infection. Changes in lipid profiles, TyG index, and homeostasis model assessment of insulin resistance (HOMA-IR) were evaluated from baseline to SVR12. Insulin resistance was defined as HOMA-IR ≥ 2.5. The optimal TyG index cut-off for predicting insulin resistance was determined using the Youden Index. Results: A total of 111 patients (median age: 61.0 years; 45.9% male) were included. The TyG index correlated positively with HOMA-IR (Pearson’s r = 0.32, p < 0.001). Among patients with pre-existing insulin resistance, significant improvements were observed at SVR12 in both HOMA-IR (4.0 [IQR: 3.1–5.4] vs. 2.5 [IQR: 2.0–3.9]; p < 0.001) and TyG index (8.47 [IQR: 8.08–8.68] vs. 8.36 [IQR: 8.00–8.71]; p = 0.028). Using 8.27 as the optimal TyG index cut-off, similar improvements were noted in HOMA-IR (2.8 [IQR: 2.0–4.3] vs. 2.3 [IQR: 1.5–3.8]; p = 0.031) and TyG index (8.62 [IQR: 8.46–8.83] vs. 8.52 [IQR: 8.27–8.89]; p = 0.003). Conclusions: The TyG index is a valuable tool for monitoring changes in insulin resistance after HCV eradication, particularly in patients with baseline insulin resistance. Full article

SARS-CoV-2 is classified as a containment level 3 (CL3) pathogen, limiting research access and antiviral testing. To address this, we developed a non-infectious viral surrogate system using reverse genetics to generate sub-genomic replicons. These replicons contained the nsp1 mutations K164A and H165A and had the spike, membrane, ORF6, and ORF7a coding sequences replaced with various reporter and selectable marker genes. Replicons based on the ancestral Wuhan Hu-1 strain and the Delta variant of concern were replication-competent in multiple cell lines, as assessed by Renilla luciferase activity, fluorescence, immunofluorescence staining, and single-molecule fluorescent in situ hybridization. Antiviral assays using transient replicon expression showed that remdesivir effectively inhibited both replicon and viral replication. Ritonavir and cobicistat inhibited Delta variant replicons similarly to wild-type virus but did not inhibit Wuhan Hu-1 replicon replication. To further investigate the impact of nsp1 mutations, we generated a recombinant SARS-CoV-2 virus carrying the K164A and H165A mutations. The virus exhibited attenuated replication across a range of mammalian cell lines, was restricted by the type I interferon response, and showed reduced cytopathic effects. These findings highlight the utility of sub-genomic replicons as reliable CL2-compatible surrogates for studying SARS-CoV-2 replication and drug activity mechanisms. Full article

This paper describes an experimental investigation on the spread of a virus in a business jet cabin and the potential of ionization to reduce the pathogen load. In contrast to priorly investigated recirculation air cleaning, ionization can act directly in the cabin by introducing ions into the supply air. Tests were performed by emitting a surrogate virus through a breathing head in a business jet mock-up. The results allow for the conclusion that ionization technology, along with increased airflow, is a well-suited tool to sanitize cabins. Additionally, the effect of ionization on particles was investigated where it became obvious that the presence of particles reduces the ion level; however, the presence of ions hardly impact particles. Full article

Respiratory syncytial virus (RSV) remains a significant global health threat, especially to infants, the elderly, and immunocompromised individuals. This review comprehensively explores the progress in RSV vaccine development, the immune evaluation methods, and immunological surrogate. The RSV fusion (F) protein, a primary target for vaccine development, has been engineered in prefusion conformation to elicit potent neutralizing antibodies, while the attachment (G) glycoprotein and other immunogens are also being explored to broaden immune responses. Advances in diverse vaccine platforms, ranging from live attenuated and protein subunit vaccines to cutting-edge mRNA- and nanoparticle-based formulations, highlight the field’s progress, yet challenges in balancing safety, immunogenicity, and durability persist. Central to these efforts is the identification and validation of immunological surrogates, which may serve as critical benchmarks for vaccine efficacy. Neutralizing antibody titers, multifunctional T cell responses, and B cell memory have emerged as key correlates of protection. However, the feasibility of these surrogates depends on their ability to predict clinical outcomes across diverse populations and settings. While neutralizing antibodies block the virus directly, T cell responses are essential for clearing infected cells and preventing severe disease, and B cell memory ensures long-term immunity. Integrating these immunological markers into a cohesive framework requires standardized assays, robust clinical validation, and an in-depth understanding of RSV-induced immune response. Full article