#Oropouche virus disrupts #neurodevelopment and exhibits #congenital infection potential

 

Abstract

Oropouche virus (OROV) historically caused a self-limiting disease, yet recent strains have been clinically linked to congenital infection and neurodevelopmental disease. These observations highlight the need to study OROV as a congenital pathogen. Here, using both a historical and currently circulating strain, we show OROV infects neurons across differentiation states in human forebrain organoids. Compared with the neurotropic congenital pathogen Zika virus (ZIKV), OROV exhibits a heightened capacity for neuroinfection and pathology in both forebrain organoids and neonatal mice. The increased permissiveness of OROV is driven, in part, by a broader neuronal tropism and a relative insensitivity to neuronal type I interferon-mediated antiviral responses. Consistent with clinical observations, neonatal neuroinfection results in rapid and severe neuropathology marked by cerebral hemorrhage. Finally, using a transient type I interferon-blockade model, we demonstrate that OROV can productively infect the murine placenta and cause fetal growth restriction. Together, our complementary models support a unified framework in which placental and fetal barriers limit productive fetal brain infection, yet OROV exhibits marked neurotropism and neuropathogenic potential upon gaining access to developing neural tissues. These findings reinforce the need for vigilant monitoring of OROV as an emerging pathogen associated with adverse pregnancy outcomes and congenital disease.

Source: 

Link: https://doi.org/10.1038/s41467-026-77859-5

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Trimester-dependent vertical #transmission of #H5N1 #influenza virus through #placental and mammary routes impairs offspring development

 

Abstract

Avian influenza H5N1 has pandemic potential and historically causes more severe disease in pregnant women than the general population. With increasing transmission of H5N1 detected among placental mammals, animal models are necessary for testing countermeasures, including during pregnancy. Pregnant outbred mice infected with a contemporary strain of bovine H5N1 during the second trimester equivalent causes in utero transmission, with infectious virus detected in the uterus, placenta, and fetus. Birth following third trimester infection results in offspring with decreased size, neurodevelopmental delays, and adolescent behavioral impairments, with infectious virus detected in the neonatal milk ring and lungs, as well as mammary tissues. H5N1 viral protein colocalizes with trophoblast cells in the placenta and epithelial cells in mammary tissue that spatially overlap with lectins for α2,3-linked SA. With the pandemic potential of H5N1, our vertical transmission model in placental mammals is essential for understanding viral spread and evaluating treatments during pregnancy.

Source: 

Link: https://www.nature.com/articles/s41467-026-76891-9

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#Nipah virus #Malaysia and #Bangladesh strain-induced #pathogenesis in mice lacking type I #interferon receptor signaling

 

Abstract

Nipah virus (NiV) is a zoonotic highly pathogenic Paramyxovirus inducing lethal outbreaks of encephalitis and Acute Respiratory Distress Syndrome (ARDS) with an average case-fatality rate of 75%. Two viral strains, NiV-Malaysia (NiV-Mal) and NiV-Bangladesh (NiV-Ban), associated to distinct route of transmission, symptoms and lethality have been described. Due to the permanent threat of these emerging infections and the lack of approved therapeutics, it is crucial to improve our understanding regarding NiV-associated pathogenesis. Mice represent a small and accessible animal model, provided with numerous biological tools for the functional assessment of different genes related to antiviral response. Here, we explore the susceptibility of mice deficient for type I interferon receptor (IFNAR KO) to inoculation with either NiV-Mal or NiV-Ban through intraperitoneal or intranasal routes. Our results complement observations showing that IFNAR KO mice are susceptible to NiV-Ban infection via intraperitoneal route, although to a lesser extent than NiV-Mal, and develop encephalitis and a pulmonary syndrome with viral dissemination to various organs. Additionally, intranasal administration of both viral strains exhibited a subclinical infection with viral replication in the brain and the lungs along to the production of neutralizing antibodies in some animals. These results suggest that IFNAR KO mice may represent a reliable model permitting comparative studies of the immunopathogenesis induced by both NiV-Mal and NiV-Ban infections.

Source: 

Link: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0013894

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Characterization of atypical #Ebola virus disease in #ferrets

 

Abstract

Ebola virus (EBOV) infection typically results in severe—and often lethal—acute disease. However, increasing evidence suggests that EBOV can persist in certain immune-privileged tissues, which may then serve as reservoirs for the later reemergence of EBOV and disease recrudescence. Here, we report atypical EVD recrudescence in a ferret model inoculated with an otherwise lethal dose of EBOV and treated with low doses of a highly potent monoclonal antibody cocktail. Among 32 antibody-treated ferrets, 14 animals survived, while 8 succumbed to acute EVD within about 5–8 days. The remaining 10 animals succumbed to atypical EVD between 12 and 18 days post-infection (DPI) despite having shown no, or very minor, signs of illness during the acute phase of disease. While viremia disappeared by 14 DPI in most animals that succumbed to atypical EVD, it rebounded modestly just prior to death. Unlike animals that died of acute EVD, those that died of atypical EVD showed only a moderate systemic inflammatory response and few signs of organ dysfunction, in line with low levels of virus in the liver and spleen. Interestingly, however, ferrets that died of atypical EVD showed high levels of virus in the brain, consistent with increased markers of inflammation in the central nervous system and significant pathological changes, including a breakdown in the blood-brain barrier and severe meningoencephalitis. Not only does this study shed important light on the atypical and underappreciated manifestations of EVD, but it also establishes the ferret as a valuable model of EBOV recrudescence.

Source: 

Link: https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1013916

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Mild #SARS-CoV-2 #maternal #infection in mice induces transient offspring #neurodevelopmental aberrance

 

Significance

The rising global numbers of SARS-CoV-2 infections highlight the need to assess potential neurodevelopmental and psychiatric impact in children born to infected mothers. Human cohorts have provided conflicting conclusions, while mouse studies have focused on moderate-to-severe infection despite most infections in pregnant women being mild or asymptomatic. Our study shows that mild, respiratory tract–restricted SARS-CoV-2 infection in pregnant mice was sufficient to cause placental inflammation and transient changes in offspring brain gene expression, without altering gross brain structure or behavior under our experimental conditions. These findings suggest that soluble factors induced by maternal respiratory infection mediate placental inflammation and changes in offspring brain gene expression during the fetal and neonatal periods, which resolve in later childhood.

Abstract

Maternal viral infection during pregnancy has been identified as a risk factor for psychiatric disorders and neurodevelopmental abnormalities in offspring. With cumulative SARS-CoV-2 infections now numbering in the hundreds of millions globally, there is a need to evaluate the effects of maternal SARS-CoV-2 infection on offspring brain development and behavior. We developed a mouse model of mild COVID-19 during pregnancy in which SARS-CoV-2 infection is restricted to the respiratory tract. Infected mothers did not show weight loss or changes in litter size, but did exhibit detectable local and systemic immune responses, including placental inflammation. Characterization of the offspring’s cerebral cortex revealed transcriptomic changes in the fetus at E15 and on postnatal day 5 (P5), but no gross alterations in cytoarchitecture, synaptic density, or microglial abundance. We did not detect any significant changes in open-field or novel object recognition tests in P50 offspring born to SARS-CoV-2-infected dams. These findings suggest that mild maternal respiratory SARS-CoV-2 infection induces soluble factors that mediate placental inflammation and transient cerebral cortex alterations in offspring that resolve by later childhood.

Source: 

Link: https://www.pnas.org/doi/abs/10.1073/pnas.2518294123?af=R

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#Influenza A Virus #Infection Impairs #Neuronal Activity in Human iPSC-Derived NGN2 Neural Co-Cultures

 

Abstract

Influenza A virus (IAV) infection is associated with a wide variety of neurological complications, of which mild complications like impaired cognitive functioning are most prominent. Even though several studies have shown that many influenza viruses can enter the CNS, the neuropathogenesis of seasonal (H3N2 and H1N1) and pandemic (pH1N1 2009) IAV infections is poorly understood. Therefore, we aimed to investigate the cellular tropism, replication efficiency and associated functional consequences using a human stem cell-derived neural co-culture model of neurons and astrocytes. All viruses were able to infect neurons in the co-culture model, although this infection did not result in efficient replication and release of progeny virus. In addition, infection did not result in visible cell death or apoptosis. However, functional analyses revealed that IAV inoculation resulted in a reduction of spontaneous neural activity and a partial reduction of neural excitability. This study shows that seasonal and pandemic IAVs can disrupt neural homeostasis, without efficient virus replication or the induction of cell death. However, these functional changes in neural activity can contribute to cognitive problems during IAV infections in the acute and potentially post-acute phase of the infection.

Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

ZonMw, The Dutch Organisation for knowledge and innovation in health, healthcare and well-being, https://ror.org/01yaj9a77, 91718308

The netherlands organisation for scientific research, OCENW.XS22.2.045, 024.003.001

Escmid, xx

European Union, 101084171

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.08.26.672266v1

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#COVID19-associated #neuroinflammation and #astrocyte death in the #brain linked to ORF3a-induced activation of Sur1-mediated ion channels

 

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic has disproportionately affected individuals with pre-existing medical conditions, such as neurocognitive disorders. Premorbid neurocognitive conditions compounded by COVID-19 can escalate into COVID-associated neurological complications, leading to severe illness or even death. As COVID-19 continues to persist and vaccines lose efficacy against emerging variants, individuals with neurocognitive disorders often experience prolonged symptoms that are further exacerbated by repeated breakthrough infections of highly diversified viral variants due to emergence of new viral mutations. Despite the significance of neurocognitive disorders as risk factors for COVID-19-related mortality and long COVID, the underlying causes remain largely unknown. In this study, we report a link between ORF3a expression and COVID-associated neuroinflammation and neurocytotoxicity in postmortem brain tissues from COVID-19 patients. These findings were further verified through neural cell-based in vitro and in vivo animal studies introducing ORF3a either alone or in the context of viral infection. As a membrane-associated protein, ORF3a induces upregulation of Sur1-regulated ion channels, resulting in intracellular Ca2+ influx, apoptosis, and necrosis through both NF-kB-dependent and independent proinflammatory responses in astrocytes. These findings reveal a novel clinical and mechanistic link between ORF3a and Sur1-regulated ion channels, which are highly responsive to neuroinflammatory conditions causing neurodegeneration. Additionally, we have identified a Food and Drug Administration-approved drug, glibenclamide, and a natural antiviral compound glycyrrhizin that effectively mitigates the neuropathological effects of ORF3a, underscoring the therapeutic potential and clinical significance of these findings.

Source: mBio, https://journals.asm.org/doi/full/10.1128/mbio.02012-25?af=R

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