ABSTRACT ADP-ribosyltransferases (ARTs) mediate the transfer of ADP-ribose from NAD + to protein or nucleic acid substrates. This modification can be removed by several different types of proteins, including macrodomains. Several ARTs, also known as PARPs, are stimulated by interferon, indicating ADP-ribosylation is an important aspect of the innate immune response. All coronaviruses (CoVs) encode for a highly conserved macrodomain (Mac1) that is critical for CoVs to replicate and cause disease, indicating that ADP-ribosylation can effectively control coronavirus infection. Our siRNA screen indicated that PARP12 might inhibit the replication of a MHV Mac1 mutant virus in bone-marrow derived macrophages (BMDMs). To conclusively demonstrate that PARP12 is a key mediator of the antiviral response to CoVs both in cell culture and in vivo , we produced PARP12 −/− mice and tested the ability of MHV A59 (hepatotropic/neurotropic) and JHM (neurotropic) Mac1 mutant viruses to replicate and cause disease in these mice. Notably, in the absence of PARP12, Mac1 mutant replication was increased in BMDMs and in mice. In addition, liver pathology was also increased in A59 infected mice. However, the PARP12 knockout did not restore Mac1 mutant virus replication to WT virus levels in all cell or tissue types and did not significantly increase the lethality of Mac1 mutant viruses. These results demonstrate that while PARP12 inhibits MHV Mac1 mutant virus infection, additional PARPs or innate immune factors must contribute to the extreme attenuation of this virus in mice. IMPORTANCE Over the last decade, the importance of ADP-ribosyltransferases (ARTs), also known as PARPs, in the antiviral response has gained increased significance as several were shown to either restrict virus replication or impact innate immune responses. However, there are few studies showing ART-mediated inhibition of virus replication or pathogenesis in animal models. We found that the CoV macrodomain (Mac1) was required to prevent ART-mediated inhibition of virus replication in cell culture. Here, using knockout mice, we found that PARP12, an interferon-stimulated ART, was required to repress the replication of a Mac1 mutant CoV both in cell culture and in mice, demonstrating that PARP12 represses coronavirus replication. However, the deletion of PARP12 did not fully rescue Mac1 mutant virus replication or pathogenesis, indicating that multiple PARPs function to counter coronavirus infection.

Aryl hydrocarbon receptor (AHR) signalling integrates biological processes that sense and respond to environmental, dietary, and metabolic challenges to ensure tissue homeostasis. AHR is a transcription factor that is inactive in the cytosol but upon encounter with ligand translocates to the nucleus and drives the expression of AHR targets, including genes of the cytochrome P4501 family of enzymes such as Cyp1a1 . To dynamically visualise AHR activity in vivo, we generated reporter mice in which firefly luciferase ( Fluc ) was non-disruptively targeted into the endogenous Cyp1a1 locus. Exposure of these animals to FICZ, 3-MC or to dietary I3C induced strong bioluminescence signal and Cyp1a1 expression in many organs including liver, lung and intestine. Longitudinal studies revealed that AHR activity was surprisingly long-lived in the lung, with sustained Cyp1a1 expression evident in discrete populations of cells including columnar epithelia around bronchioles. Our data link diet to lung physiology and also reveal the power of bespoke Cyp1a1-Fluc reporters to longitudinally monitor AHR activity in vivo.

Exposure to multiple mosquito-borne flaviviruses within a lifetime is not uncommon; however, how sequential exposures to different flaviviruses shape the cross-reactive (CR) humoral response against an antigen from a different serocomplex has yet to be explored. Here, we report that dengue-infected individuals initially primed with the Japanese encephalitis virus (JEV) showed broadly highly neutralizing potencies against the Zika virus (ZIKV). We also identified a rare class of ZIKV CR human monoclonal antibodies (huMAbs) with increased somatic hypermutation and broad neutralization against multiple flaviviruses. One huMAb, K8b, binds quaternary epitopes with heavy and light chains separately interacting with overlapping E dimer units spanning domains I, II, and III through cryo-electron microscopy and structure-based mutagenesis. Using JEV virus-like particle (VLP) immunization in mice further confirmed that such CR antibodies, mainly IgG3 isotype, can be induced and proliferate through heterologous DENV-2 VLP stimulation. Our findings provide novel insights for future vaccination strategies.

ABSTRACT Rapid, simple, and low-cost diagnostic technologies are crucial tools for combatting infectious disease. Here, we describe a class of aptamer-based RNA switches called aptaswitches that recognize specific target nucleic acid molecules and respond by initiating folding of a reporter aptamer. Aptaswitches can detect virtually any sequence and provide a fast and intense fluorescent readout, generating signals in as little as 5 minutes and enabling detection by eye with minimal equipment. We demonstrate that aptaswitches can be used to regulate folding of six different fluorescent aptamer/fluorogen pairs, providing a general means of controlling aptamer activity and an array of different reporter colors for multiplexing. By coupling isothermal amplification reactions with aptaswitches, we reach sensitivities down to 1 RNA copy/µL in one-pot reactions. Application of multiplexed one-pot reactions against RNA extracted from clinical saliva samples yields an overall accuracy of 96.67% for detection of SARS-CoV-2 in 30 minutes. Aptaswitches are thus versatile tools for nucleic acid detection that can be readily integrated into rapid diagnostic assays.

The emergence of a highly contagious novel coronavirus in 2019 led to an unprecedented need for large scale diagnostic testing. The associated challenges including reagent shortages, cost, deployment delays, and turnaround time have all highlighted the need for an alternative suite of low-cost tests. Here, we demonstrate a diagnostic test for SARS-CoV-2 RNA that provides direct detection of viral RNA and eliminates the need for costly enzymes. We employ DNA nanoswitches that respond to segments of the viral RNA by a change in shape that is readable by gel electrophoresis. A new multi-targeting approach samples 120 different viral regions to improve the limit of detection and provide robust detection of viral variants. We apply our approach to a cohort of clinical samples, positively identifying a subset of samples with high viral loads. Since our method directly detects multiple regions of viral RNA without amplification, it eliminates the risk of amplicon contamination and renders the method less susceptible to false positives. This new tool can benefit the COVID-19 pandemic and future emerging outbreaks, providing a third option between amplification-based RNA detection and protein antigen detection. Ultimately, we believe this tool can be adapted both for low-resource onsite testing as well as for monitoring viral loads in recovering patients.

The Zika virus (ZIKV) emerged in Brazil in 2015, causing large outbreaks across South America and the Caribbean. In the years that followed, many countries in these areas reported exceptionally low circulation of Dengue virus (DENV), which later resurged in 2018-2019. Several hypotheses have been proposed to explain low DENV transmission, yet no consensus has been reached so far. We show that while short-term cross-protection induced by ZIKV can explain the temporary disappearance of DENV, it also predicts, in contrast with observations, a rising mean age of DENV incidence in the post-ZIKV era. We further demonstrate that disease enhancement of DENV, especially in primary infections in ZIKV-positive hosts, is required to remedy these shortfalls. Our results suggest that both population-level immunity to DENV and ZIKV contributed positively to the reduction in mean age of DENV incidence.

ABSTRACT Oligoadenylate synthetase 3 (OAS3) and Ribonuclease L (RNase L) are components of a mammalian RNA decay pathway that is critical for combating viral infection. Nevertheless, the subcellular localization of OAS3 and RNase L during the antiviral response has remained elusive. Herein, we show that upon activation in response to double-stranded RNA or viral infection, OAS3 and RNase L integrate into higher-order cytoplasmic assemblies distinct from stress granules (SGs), RNase L-induced bodies (RLBs), or processing bodies (P-bodies). We identified these assemblies as double-stranded RNA-induced foci (dRIF), which also contain activated protein kinase R (PKR). We observed incorporation of RNase L, OAS3, and PKR in dRIFs during Zika virus and dengue virus infection. Our data support that condensation of dsRNA, OAS3 and RNase L at dRIFs promotes the homodimerization and oligomerization of RNase L required for its rapid activation, demonstrating a fundamental role for biological condensates in activating antiviral signaling.

Emerging infectious disease threats are becoming more frequent due to various social, political and geographical pressures including increased human-animal contact, global trade, transportation and changing climate conditions. As a result, the threat that emerging agents can be spread by blood contact or transfusion of blood products also becomes increasingly problematic. Blood transfusion is essential in treating patients with anemia, blood loss, and other medical conditions. However, these lifesaving components can become a vector for spreading diseases, particularly to vulnerable populations. New methods have been implemented on a global basis for prevention of transfusion transmission via plasma, platelet, and whole blood products. Implementing proactive pathogen reduction methods can significantly reduce the likelihood of disease transmission via blood transfusion, even for newly emerging agents whose transmissibility and susceptibility are still being evaluated as they emerge. In this review, we consider the Mirasol PRT system for blood safety which is based on a photochemical method involving Riboflavin and UV light. We provide examples of how emerging threats such as Ebola, SARS-CoV-2, Hepatitis E, monkeypox and other agents have been evaluated in real time regarding effectiveness of this method for reducing the likelihood of disease transmission via transfusion. Keywords: transfusion; blood; pathogen reduction; emerging infectious diseases.

Abstract Biomolecules continually sample alternative conformations. Consequently, even the most energetically favored ground conformational state has a finite lifetime. Here, we show that, in addition to the 3D structure, the lifetime of a ground conformational state determines its biological activity. Using hydrogen-deuterium exchange nuclear magnetic resonance spectroscopy, we found that Zika virus exoribonuclease-resistant RNA (xrRNA) encodes a ground conformational state with a lifetime that is ~10 5 –10 7 longer than that of canonical base pairs. Mutations that shorten the apparent lifetime of the ground state without affecting its 3D structure decreased exoribonuclease resistance in vitro and impaired virus replication in cells. Additionally, we observed this exceptionally long-lived ground state in xrRNAs from diverse infectious mosquito-borne flaviviruses. These results demonstrate the biological significance of the lifetime of a preorganized ground state and further suggest that elucidating the lifetimes of dominant 3D structures of biomolecules may be crucial for understanding their behaviors and functions.

The COVID-19 pandemic has had a profound impact on global health, leading to significant morbidity and mortality. Pregnancy can weaken the maternal immune response to the SARS-CoV-2 virus and increase the risk of severe adverse outcomes for both mother and fetus or newborn. Despite the well-known effects of viruses on pregnancy and the potential association with congenital anomalies, the impact of COVID-19 on pregnancy is still not fully understood. Here we systematically gathered and analyzed data from studies reporting the effects of maternal COVID-19 infection on mothers and their newborns. Through a comprehensive search of the PubMed, EMBASE, and Cochrane Library databases, 20 relevant studies were identified. Our analysis revealed that pregnant women with COVID-19 are at higher risk of morbidity and mortality and are more likely to require admission to the intensive care unit. Their newborns are also at increased risk of premature birth, low birth weight, and admission to neonatal intensive care unit. Our findings highlight the vulnerability of pregnant women and their newborns to COVID-19 complications and underscore the need for further research to better understand modes of neonatal SARS-CoV-2 transmission and the potential for congenital anomalies in early pregnancy infections.

Despite numerous studies highlighting the higher transmissibility of the African Zika virus (ZIKV) lineage compared to the Asian lineage in mosquito vectors, little is known about how the viruses interact with different tissues during the early steps of mosquito infection. To address this gap, we aimed to characterize intra-host infection barriers by combining a tissue-level monitoring of infection using plaque assays and a novel quantitative analysis of single-cell level infection kinetics by in situ immunofluorescent staining. Our results revealed that, in Aedes aegypti , an African ZIKV strain exhibited a higher replication rate across various tissues than an Asian ZIKV strain. This difference was potentially due to a higher virus production in individual cells, faster spread within tissues, or a combination of both factors. Furthermore, we observed that higher bloodmeal titers resulted in a faster viral spread to neighboring cells suggesting that intra-host infection dynamics depend on inoculum size. We also identified a significant bottleneck during midgut infection establishment for both ZIKV lineages, with only a small percentage of the virus population successfully initiating infection. Finally, the in situ immunofluorescent staining technique enabled the examination of virus infection characteristics in different cell types and revealed heterogeneity in viral replication. Together, these findings demonstrate that differences in intra-host infection kinetics underlie differential transmissibility between African and Asian ZIKV lineages. This information could serve as a starting point to further investigate the underlying mechanisms and ultimately inform the development of alternative control strategies. Importance The recent Zika virus (ZIKV) epidemic in the Americas highlights its potential public health threat. While the Asian ZIKV lineage has been identified as the main cause of the epidemic, the African lineage, which has been primarily confined to Africa, has shown evidence of higher transmissibility in Aedes mosquitoes. To gain a deeper understanding of this differential transmissibility, our study employed a combination of tissue-level infection kinetics and single-cell level infection kinetics using in situ immunofluorescent staining. We discovered that the African ZIKV lineage propagates more rapidly and spreads more efficiently within mosquito cells and tissues than its Asian counterpart. This information lays the groundwork for future exploration of the viral and host determinants driving these variations in propagation efficiency.

Probably one of the biggest global challenges is viral epidemics, nowadays. The COVID-19 crisis proved that the more foresight we have to find effective compounds in various aspects, the better we can deal with viral epidemics. Different types of viruses directly or indirectly affect liver function. Therefore, an important aspect of combating viral infections is protecting the liver as a vital human organ.Natural compounds as a rich source of potential hepatoprotective drugs have been interested. Several in vitro and in vivo researches have been conducted to investigate the effectiveness of phytochemicals and vitamins on liver failure caused by a viral infection, but few of these compounds have been studied in the clinical phase, and most of them have had acceptable effectiveness. In this review, we focused on the findings of clinical studies that have addressed the role of phytochemicals and vitamins in reversing liver dysfunction associated with viral infections.

Objective: To rigorously assess infant growth and neurodevelopment during the first six months of life, we assessed outcomes in a prospective cohort of infants exposed to COVID-19 in utero and compared those outcomes to matched controls. Methods: A prospective cohort of pregnant women with documented COVID-19 during pregnancy were recruited. Infant growth parameters were collected at delivery, two and six months postpartum. Parent and clinician standardized development assessments (Ages and Stages Questionnaire and Bayley) were completed at two and six months. Paired and unpaired t-tests were used to compare infant neurodevelopment over time and to pre-pandemic and pandemic matched controls, respectively. Results: From 26 pregnant women recruited, 25 (96%) deliveries, 18 (69%) 2-month, and 16 (61%) 6-month visits were completed. SARS-CoV-2 infections occurred in 1st trimester (8%), 2nd trimester (23%), 3rd trimester (46%), and at delivery (23%). Growth trajectories and developmental scores compared to the standards were normal for exposed infants except for one child who demonstrated developmental delay in more than one domain at 6 months. When compared to controls, exposed children scored lower in the Bayley-IV cognitive domain (102.7; standard deviation (SD):14.7) compared to pre-pandemic (117.8; SD:14.6; p=0.002) and pandemic (116.6; SD:12.6; p=0.008) geographically matched controls but not external pre-pandemic controls (109.7; SD:11.9; p=0.09). There were no other differences in other domains. Conclusions: Infants exposed to COVID-19 during pregnancy may be at risk for mild adverse neurodevelopmental outcomes and should be routinely screened using standardized tools at well-child visits.

ABSTRACT The Zika virus (ZIKV) outbreak in Brazil between 2015 and 2016 was associated with an increased prevalence of severe congenital malformations, including microcephaly. Notably, the distribution of microcephaly cases was not uniform across the country, with a disproportionately higher incidence recorded in the Northeast region (NE). Our previous work demonstrated that saxitoxin (STX), a toxin ubiquitously present in the drinking water reservoirs of the NE, exacerbated the damaging effects of ZIKV on the developing brain. In the present study, we hypothesized that STX’s impact might vary among different neural cell types. Our experimental observations suggest that exposure to STX potentiates the neurotoxic effect of Zika Virus (ZIKV) on human neuronal cells. However, while ZIKV infection demonstrated severe impacts on astrocytes and neural stem cells (NSCs), the addition of STX did not exacerbate these effects. We observed that neurons subjected to STX exposure were more prone to apoptosis and displayed a higher number of ZIKV-infected cells. These findings suggest that STX exacerbates the harmful effects of ZIKV on neurons, thereby providing a plausible explanation for the heightened severity of ZIKV-induced congenital malformations observed in Brazil’s NE. This study underscores the importance of understanding the interactive effects of environmental toxins and infectious pathogens on neural development, with potential implications for public health policies and interventions.

Aim Rapid intervention development, implementation and evaluation is required for emergency public health contexts, such as the recent COVID-19 pandemic. A novel Agile Co-production and Evaluation (ACE) framework has been developed to assist this endeavour in future public health emergencies. This scoping review aimed to map available behavioural science resources that can be used to develop and evaluate public health guidance, messaging, and interventions in emergency contexts onto components of ACE: rapid development and implementation, co-production with patients or the public including seldom heard voices from diverse communities, and inclusion of evaluation. Methods A scoping review methodology was used. Searches were run on MEDLINE, EMBASE, PsychInfo, and Google, with search terms covering emergency response and behavioural science. Papers published since 2014 and which discussed a framework or guidance for using behavioural science in response to a public health emergency, were included. A narrative synthesis was conducted. Results Seventeen records were included in the synthesis. The records covered a range of emergency contexts, the most frequent of which were COVID-19 (n=7) and non-specific emergencies (n=4). One record evaluated existing tools, six proposed new tools, and ten described existing tools. Commonly used tools included the Behavioural Change Wheel, Capability, Opportunity, and Motivation Behaviour model (COM-B model) and social identity theory. Three records discuss co-production with the target audience and consideration of diverse populations. Four records incorporate rapid testing, evaluation, or validation methods. Six records state that their tool is designed to be implemented rapidly. No records cover all components of ACE. Conclusion We recommend that future research explores how to create guidance involving rapid implementation, co-production with patients or the public including seldom-heard voices from diverse communities, and evaluation.

Coronavirus disease 2019 (COVID-19) shares similar immune characteristics with autoimmune diseases like systemic lupus erythematosus (SLE). However, such associations have not yet been investigated at the single-cell level. Thus, in this study, we integrated and analyzed RNA sequencing results from different patients and normal controls from the GEO database and identified subsets of immune cells that might involve in the pathogenesis of SLE and COVID-19. We also disentangled the characteristic alterations in cell and molecular subset proportions as well as gene expression patterns in SLE patients compared with COVID-19 patients. Key immune characteristic genes (such as CXCL10 and RACK1) and multiple immune-related pathways (such as the coronavirus disease-COVID-19, T-cell receptor signaling, and MIF-related signaling pathways) were identified. We also highlighted the differences in peripheral blood mononuclear cells (PBMCs) between SLE and COVID-19 patients. Moreover, we provided an opportunity to comprehensively probe underlying B-cell‒cell communication with multiple ligand‒receptor pairs (MIF-CD74 + CXCR4, MIF-CD74 + CD44) and the differentiation trajectory of B-cell clusters that is deemed to promote cell state transitions in COVID-19 and SLE. Our results demonstrate the immune response differences and immune characteristic similarities, such as the cytokine storm, between COVID-19 and SLE, which might pivotally function in the pathogenesis of the two diseases and provide potential intervention targets for both diseases.

Zika virus (ZIKV) and Dengue Virus (DENV) share a lot of similarities, being both flaviviruses and neglected tropical diseases that cause a worldwide burden that is increasing with climate change. Studying the interactions of cell recptors and viruses is essential to further the knowledge and development of ways to prevent and control flaviviral diseases. An important interaction occurs between the envelopeof the two viruses and a protein on the surface of immune cells, called DC-SIGN. We describe this interaction in a structural comparison involving homology modeling of these proteins, guided docking based on deposited crystallography, molecular dynamics of the docked complexes and for the decomposition of interacting residues we employed an analysis of the surface area accessible by the Generalized Bourne method. The region of interest for the discussion is predominantly electropositive in the DENV envelope, but when comparing the same region in the ZIKV envelope, we can observe that there is a decrease in charges, not to the point of making the region electronegative as a whole, but enough for the surroundings of the interaction region to become neutral with electronegative trends. These results suggest better interaction of ZIKV with the DC-SIGN receptor, particularly in the CRD portion

Improving antigen presentation is crucial for the success of immunization strategies. Yeasts are classically used as biofactories to produce recombinant proteins and are efficient vehicles for the delivery of vaccine antigens, besides present adjuvants properties. Despite the absence of epidemic outbreaks, several vaccine approaches continue to be developed for Zika virus infection. These prophylactic strategies are fundamental given the severity of clinical manifestations, mainly due to viral neurotropism. The present study aimed to evaluate in vivo the immune response induced by P. pastoris recombinant strains displaying epitopes of the Envelope (ENV) and NS1 ZIKV proteins. Intramuscular immunization with heat-attenuated yeast enhanced the secretion of IL-6, TNF-α, and IFN-γ, besides activation of CD4+ and CD8+ T cells, in BALB/c mice. P. pastoris displaying ENV epitopes induced a more robust immune response, increasing immunoglobulin production, especially IgG isotypes. Both proposed vaccines showed the potential to induce immune responses without adverse effects, confirming the safety of administering P. pastoris as a vaccine vehicle. Here we demonstrated, for the first time, the evaluation of a vaccine against ZIKV based on a multiepitope construct, using yeast as a vehicle, reinforcing the applicability of P. pastoris as a whole yeast cell vaccine.

The emergence of novel pathogens is a well-known epidemiological risk, however, the unexpected emergence of a truly novel coronavirus-mediated pandemic, SARS-nCOV2 (COVID-19), underscored the significance of understanding this contagion. The COVID-19 pandemic caused unprecedented social, economic, and educational disruptions on a scale never seen before. In addition to social protocols, the development of safe, effective, affordable COVID-19 vaccines was developed within months, the cornerstone to mitigating this pandemic. We present an overview of the evolution of the SARS-nCOV2 pandemic from a historical perspective and describe its biology and behavior, especially the immunological aspects of the disease. We further provide an overview of COVID-19 therapeutics, treatment, and vaccine development. It is critical to understand the transmission mechanism of the disease to control and mitigate its progression. We describe cohort studies to identify secondary and tertiary syndromes. The transmission characteristics help its diagnosis and detection. During the pandemic, a lot of emphasis was placed on personal protection equipment. It is now concluded that the virus particles spread by aerosol dispersion. While the recommended distance may not be sufficient, the use of personal protective equipment and social distancing may be helpful in close-quarters environments. Such protocols in conjunction with safe and effective vaccines and personal hygiene are among the safe practices. While we learn from our experience, this review provides a holistic view of COVID-19, so we are better prepared for a future pandemic. In addition to a wide-spectrum automated analytics system, we also suggest that the use of artificial intelligence in conjunction with data analytics can further reduces the risk of speculatively diagnosing agents incorrectly, to eliminate future pandemic, where the novelty can be the cloud-based presumptive diagnosis.

The Zika virus (ZIKV) epidemic brought new discoveries regarding arboviruses, especially flaviviruses, as ZIKV was described as sexually and vertically transmitted. The latter shows severe consequences for the embryo/fetus, such as congenital microcephaly and deficiency of the neural system, currently known as Congenital ZIKV Syndrome (CZS). To better understand ZIKV dynamics in trophoblastic cells present in the first trimester of pregnancy (BeWo, HTR-8, and control cell HuH-7), an experiment of viral kinetics was performed for African MR766 low passage and Asian-Brazilian IEC ZIKV lineages. The results were described independently, and demonstrated that the three placental cells lines are permissive and susceptible to ZIKV. We noticed cytopathic effects that are typical in vitro viral infection in BeWo and HTR-8. Regarding kinetics, MR766lp showed peaks of viral loads in 24 and 48 hpi for all cell types tested, as well as marked cells death after peak production. On the other hand, HTR-8 lineage inoculated with ZIKV-IEC exhibited increased viral production in 144 hpi, with a peak between 24 and 96 hpi. Furthermore, IEC had peak variations of viral production for BeWo in 144 hpi. Both cells types continued alive during the process of viral replication. Considering such in vitro results, the hypothesis that maternal-fetal transmission is probably a way of virus transmission between the mother and the embryo/fetus is maintained.

Rabies is an ancient neuroinvasive viral (genus Lyssavirus, family Rhabdoviridae) disease affecting approximately 59,000 people worldwide. The central nervous system (CNS) is targeted, and rabies has a case fatality rate of almost 100% in humans and animals. Rabies is entirely preventable through proper vaccination, and thus, the highest incidence is typically observed in developing countries, mainly in Africa and Asia. However, there are still cases in European countries and the US. Recently, demographic, increasing income levels, and the coronavirus disease 2019 (COVID-19) pandemic have caused a massive raising in the animal population, enhancing the need for preventive measures (e.g., vaccination, surveillance, animal control programs), post-exposure prophylaxis, and a better understanding of rabies pathophysiology to identify therapeutic targets, since there is no effective treatment after the onset of clinical manifestations. Here we review the neuroimmune biology and mechanisms of rabies. Its pathogenesis involves a complex and poorly understood modulation of immune and brain functions associated with metabolic, synaptic, and neuronal impairments, resulting in fatal outcomes without significant histopathological lesions in the CNS. In this context, the neuroimmunological and neurochemical aspects of excitatory/inhibitory signaling (e.g., GABA/glutamate crosstalk) are likely related to the clinical manifestations of rabies infection. Uncovering new links between immunopathological mechanisms and neurochemical imbalance will be essential to identify novel potential therapeutic targets to reduce rabies morbidity and mortality.

Background Chikungunya and Zika are both arboviruses transmitted through the Aedes mosquitoes, which are ectothermic, leading to seasonal outbreak patterns of virus infections in the human population. Mathematical models linked with mosquito trap data, human case data, or both, have proven to be powerful tools for understanding the transmission dynamics of arboviral diseases. However, while predictive models should consider a variety of features in the environment, vectors, and hosts, it is not clear which aspects are essential to assist with short-term forecasting. Methodology We consider four simple models with various assumptions, including mosquito dynamics, temperature impacts, or both, and apply each model to forecast the Chikungunya and Zika outbreaks of nine different regions in French Polynesia. We use standard statistical criteria to compare the accuracy of each model in predicting the magnitude of the outbreak to select the most appropriate model to use as an alert system for arbovirus infections. Moreover, by calibrating our “best model”, we estimate biologically meaningful parameter values to explore the commonality and difference between Chikungunya and Zika epidemics. Conclusions We show that incorporating the mosquito population dynamics in the arbovirus transmission model is essential for accurate arbovirus case prediction. In addition, such enhancement in the accuracy of prediction is more obvious for the Chikungunya data than the Zika data, suggesting that mosquito dynamics play a more important role in Chikungunya transmission than Zika transmission. In contrast, incorporating the effects of temperature may not be necessary for past outbreaks in French Polynesia. With the well-calibrated model, we observe that the Chikungunya virus has similar but slightly higher transmissibility than the Zika virus in most regions. The best-fit parameters for the mosquito model suggest that Chikungunya has a relatively longer mosquito infectious period and a higher mosquito-to-human transmission rate. Further, our findings suggest that universal vector control plans will help prevent future Zika outbreaks. In contrast, targeted control plans focusing on specific mosquito species could benefit the prevention of Chikungunya outbreaks.

Perineuronal nets (PNNs) form a specialized extracellular matrix that regulates neuronal activity. Their formation early in the postnatal period is regulated by neuronal signaling and glial activation raising concerns that the long-term neurological sequelae ascribed to perinatal viral infections could be mediated by altered PNN formation. Previously, we developed neonatal zika virus (ZIKV) infection model where mice have lifelong neurological sequelae despite resolving the acute infection. Here, we demonstrate that neonatal ZIKV infection results in a reduction of PNN formation during the acute disease with significant reduction in Wisteria floribunda agglutinin (WFA) staining and increased aggrecan and brevican degradants. Following resolution of infection, the level of WFA staining as well as levels of aggrecan and brevican in brains normalize, but there is increased frequency of abnormal or immature PNN. In adults, the impact of the perinatal infection subsides and PNN levels and morphology are not different from control mice. Of note, the reduction in PNN formation during acute infection was associated with increased expression of MMP12 and MMP19, but not MMP9, ADAMTS-4 or ADAMTS-5. Together our findings indicate that infection at the time of PNN development interferes with PNN formation, but nets can reform once the infection and inflammation subside.

Background: Primary human cytomegalovirus (HCMV) infection can be especially serious in pregnant women and cause severe consequences for newborns. We aimed to determine which metabolites, among the thousands in human sera, are strongly correlated with serious outcomes for pregnant women with HCMV. During the early stage of the pandemic, it was predicted that COVID-19 severity is correlated with serum D-xylose/xylitol levels, which has now been confirmed in two studies. Methods: Between July 2022 and February 2023, four antiviral assays were performed by Virology Research Services Ltd. to test the antiviral activities of D-xylose, a small bioactive molecule, alone or in combination with insulin against HCMV in HFF, HIV-1 NL4-3 in HeLa TZM-bl, and ZIKV African strain and SARS-CoV-2 England strain separately in VeroE6, with incubation durations of 5 days, 48 h, 48 h and 72 h post-infection, respectively. Ganciclovir, 3′-Azido-3′-deoxythymidine (AZT), monensin and remdesivir were used as controls. An immunofluorescence method was used for readouts of all viruses except for SARS-CoV-2, for which CPE was considered. Cytotoxicity was assessed by an MTT assay. Results: The results show that D-xylose exhibits antiviral activities against SARS-CoV-2, ZIKV, HCMV and HIV-1 in vitro, with preliminary selectivity indices of 11.6, 1.6, 2.1 and 2.6, respectively. Thus, D-xylose is more effective over a broader range of concentrations against HCMV and SARS-CoV-2 than against ZIKV and HIV-1. The EC50 value (in mM) for different assays must be placed in perspective; the average serum concentration of D-xylose in a healthy person is approximately 1.8 Mm. Conclusions: The properties of the cell-layer HS stimulated by D-xylose and especially unfractionated heparin (UFH)—another antiviral compound against these viruses—combined with these results challenge the conclusion that HS promotes viral infections. Trial Registration Not Applicable.

The microbiome of the mosquito Aedes aegypti is largely determined by the environment and influences mosquito susceptibility for arthropod-borne viruses (arboviruses). Larval interactions with different bacteria can influence adult Ae. aegypti replication of arboviruses, but little is known about the role that mosquito host genetics play in determining how larval-bacterial interactions shape Ae aegypti susceptibility to arboviruses. To address this question, we isolated single bacterial isolates and complex microbiomes from Ae. aegypti larvae from various field sites in Senegal. Either single bacterial isolates or complex microbiomes were added to two different genetic backgrounds of Ae. aegypti in a gnotobiotic larval system. Using 16S amplicon sequencing we show that similarities in bacterial community structures when given identical microbiomes between different genetic backgrounds of Ae. aegypti was dependent on the source microbiome, and the abundance of single bacterial taxa differed between Ae. aegypti genotypes. Using single bacterial isolates or the entire preserved complex microbiome, we tested the ability of specific microbiomes to drive differences in infection rates for Zika virus in different genetic backgrounds of Ae. aegypti . We observed that the proportion of Zika virus-infected adults was dependent on the interaction between the larval microbiome and Ae. aegypti host genetics. By using the larval microbiome as a component of the environment, these results demonstrate that interactions between the Ae. aegypti genotype and its environment can influence Zika virus infection. As Ae. aegypti expands and adapts to new environments under climate change, an understanding of how different genotypes interact with the same environment will be crucial for implementing arbovirus transmission control strategies.