The influenza virus has been the primary cause of the pandemic, posing a constant threat to human society. Due to its genetic evolution and continuous outbreak, antiviral research currently focuses on exploring a novel lead agent. A comprehensive antiviral screening discovered a marine bacterium whose extract exerted excellent efficacy against influenza viruses. Parerythrobacter sp. M20A3S10, a novel strain under the family Erythrobacteraceae, could produce carotenoids exhibiting antiviral and anticancer activity by enhancing the cellular immune system. Post-treatment of M20A3S10 extract showed outstanding therapeutic indexes: against influenza virus A/PR8 (H1N1) [selectivity index (SI) = 24.0], A/Wisconsin/15/2009 (H3N2) (SI = 30.1) and B/Florida/78/2015 (SI = 38.2). Comparably, the effectiveness was demonstrated against Zika virus (ZIKV) and dengue virus type 2 (DENV2) with an SI of 22.5 and 24.1, respectively, namely broad-spectrum activity. Of note, the antiviral responses resulted from the common replication mechanism between IAV, ZIKV, and DENV2. The stimulation of apoptosis-mediated cellular immunity prevented the viral release and protected the host, suggesting that switching from necroptosis to apoptosis is a novel antiviral target. Although the specific compound affecting the antiviral activity was not identified, its promising efficacy with broad activity will contribute to developing a strategy for preventing future pandemics.

Abstract Host factors that regulate cellular vesicular trafficking also contribute to progeny virions’ destination, thus representing as potential antiviral drug targets. Here we demonstrate that genetic deletion of ARF4, a regulator in vesicle transport, repressed multiple pathogenic RNA viral infections including Zika virus (ZIKV), influenza A virus (IAV), SARS-CoV-2 and Vesicular Stomatitis virus (VSV). ARF4 activation was stimulated upon viral infection, and viral production was rescued when reconstituted with the activated ARF4, but not the inactivated mutants. Mechanically, ARF4 deletion obstructed viral normal translocation into Golgi complex, but led to mis-sorting for lysosomal degradation, consequently caused the blockage of final release. More importantly, ARF4 targeting peptides achieved significant therapeutic efficacy against ZIKV and IAV challenge in mice by blocking ARF4 activation. Hence, we clarify the critical role of ARF4 during viral infection, providing a broad-spectrum antiviral target and the basis for further pharmaceutical development.

Although rare neurodevelopmental conditions have a large Mendelian component, common genetic variants also contribute to risk. However, little is known about how this polygenic risk is distributed among patients with these conditions and their parents, its interplay with rare variants, and whether parents’ polygenic background contributes to their children’s risk beyond the direct effect of variants transmitted to the child (i.e. via indirect genetic effects potentially mediated through the prenatal environment or ‘genetic nurture’). Here, we addressed these questions using genetic data from 11,573 patients with rare neurodevelopmental conditions, 9,128 of their parents and 26,869 controls. Common variants explained ∼10% of variance in overall risk. Patients with a monogenic diagnosis had significantly less polygenic risk than those without, supporting a liability threshold model, while both genetically undiagnosed patients and diagnosed patients with affected parents had significantly more risk than controls. In a trio-based model, using a polygenic score for neurodevelopmental conditions, the transmitted but not the non-transmitted parental alleles were associated with risk, indicating a direct genetic effect. In contrast, we observed no direct genetic effect of polygenic scores for educational attainment and cognitive performance, but saw a significant correlation between the child’s risk and non-transmitted alleles in the parents, potentially due to indirect genetic effects and/or parental assortment for these traits. Indeed, as expected under parental assortment, we show that common variant predisposition for neurodevelopmental conditions is correlated with the rare variant component of risk. Our findings thus suggest that future studies should investigate the possible role and nature of indirect genetic effects on rare neurodevelopmental conditions, and consider the contribution of common and rare variants simultaneously when studying cognition-related phenotypes.

Abstract At the start of the Zika virus (ZIKV) epidemic in 2015, ZIKV spread across South and Central America, and reached parts of the southern United States placing pregnant women at risk for fetal microcephaly, fetal loss, and other adverse pregnancy outcomes associated with congenital ZIKA syndrome (CZS). For this reason, testing of a safe and efficacious ZIKV vaccine remains a global health priority. Here we report that a single immunization with Ad26.M.Env ZIKV vaccine, when administered prior to conception, fully protects pregnant rhesus macaques from ZIKV viremia in blood and tissues with no adverse effects in dams and fetuses. Furthermore, vaccination prevents ZIKV distribution in fetal tissues including brain. ZIKV associated neuropathology was absent in offspring of Ad26.M.Env vaccinated dams, although pathology was limited in sham vaccinated controls. Vaccine efficacy is associated with induction of ZIKV neutralizing antibodies in pregnant rhesus macaques. A Phase I trial showed that Ad26.M.Env (Ad26.ZIKV.001) was safe and immunogenic in people. These data suggest the feasibility of vaccine prevention of ZCS in humans.

Neurons are post-mitotic, non-regenerative cells that have evolved fine-tuned immunological responses to maintain life-long cellular integrity; this includes resistance to common programmed cell death (PCD) pathways, including apoptosis and necroptosis. We have previously demonstrated a necroptosis-independent role for the key necroptotic kinase RIPK3 in host defense against neurotropic flavivirus infection. While this work showed that neuronal RIPK3 expression is essential for chemokine production and recruitment of peripheral immune cells to the infected CNS, the full RIPK3-dependent transcriptional signature, and the molecular mechanism underlying RIPK3-dependent transcription in neurons are incompletely understood. It also remains unclear what factors govern differential RIPK3 effector functions in different cell types. Here, we show that RIPK3 activation has distinct outcomes in primary cortical neurons when compared to mouse embryonic fibroblasts (MEFs) during Zika virus (ZIKV) infection or following sterile activation. We found that RIPK3 activation does not induce death in neurons; in these cells, RIPK3 is the dominant driver of antiviral gene transcription following ZIKV infection. While RIPK3 activation in MEF cells induces cell death, ablation of downstream cell death effectors unveils a RIPK3-dependent transcriptional program which largely overlaps with that observed in ZIKV-infected neurons. Using death resistant MEFs as a model to study RIPK3 signaling revealed that RIPK3 transcription relied on interactions with the RHIM domain-containing proteins RIPK1 and TRIF, effects mirrored in the RIPK3-dependent antiviral transcriptional signature observed in ZIKV-infected neurons. These findings suggest the pleotropic functions of RIPK3 are largely context dependent and that in cells that are resistant to cell death, RIPK3 acts as a mediator of inflammatory transcription. One Sentence Summary RHIM-domain containing proteins form a conserved signaling network capable of mediating inflammatory transcription and cell death.

Abstract Background This study delves into the complex interplay between Aedes aegypti salivary gland extract and immunological cells during Zika virus (ZIKV) infection. Focusing on key immune cells, including macrophages, dendritic cells, and mononuclear cells from human peripheral blood (PBMCs), it aims to unravel the intricate mechanisms through which mosquito saliva possibly modulates the immunological landscape, influencing ZIKV transmission, host susceptibility, and disease progression. The research sheds light on the role of mosquito saliva in enhancing viral replication and impairing cells involved in host defenses, offering new insights into arbovirus pathogenesis and potential intervention strategies. Methods Using the FIOCRUZ-PE243|2015 ZIKV strain, the research evaluates the Aedes aegypt salivary extracts (SGE's) impact on cytokine production in dendritic and macrophage cell lines, as well as its influence on the redox state and cytokine responses in human PBMCs. Flow cytometry assesses immune cell profiling, aiming to understand SGE's role in ZIKV infectivity and immune modulation. Results SGE enhances pro-inflammatory cytokine production in both dendritic cells and macrophages, while also inducing a Th2 cytokine profile, evidenced by decreased IFN-γ and increased IL-4 levels in PBMCs. Furthermore, SGE exposure leads to increased dendritic cell frequencies, altered T lymphocyte dynamics, and elevated oxidative stress markers. Conclusions It highlights how SGE not only facilitates ZIKV infection by modulating cytokine production and oxidative stress but also alters immune cell dynamics.

Zika virus (ZIKV) infection and pathogenesis are linked to the disruption of neurogenesis, congenital Zika syndrome and microcephaly by affecting neural progenitor cells. Nonstructural protein 5 (NS5) is the largest product encoded by ZIKV-RNA and is important for replication and immune evasion. Here, we studied the potential effects of NS5 on microtubules (MTs) and autophagy flux, together with the interplay of NS5 with histone deacetylase 6 (HDAC6). Fluorescence microscopy, biochemical cell-fractionation combined with the use of HDAC6 mutants, chemical inhibitors and RNA interference indicated that NS5 accumulates in nuclear structures and strongly promotes the acetylation of MTs that aberrantly reorganize in nested-like structures. Similarly, NS5 accumulates the p62 protein, an autophagic-flux marker. Therefore, NS5 alters events that are under the control of the autophagic tubulin-deacetylase HDAC6. HDAC6 appears to degrade NS5 by autophagy in a deacetylase- and BUZ domain-dependent manner and to control the cytoplasmic expression of NS5. Moreover, NS5 inhibits RNA-mediated RIG-I interferon (IFN) production, resulting in greater activity when autophagy is inhibited (i.e., effect correlated with NS5 stability). Therefore, it is conceivable that NS5 contributes to cell toxicity and pathogenesis, evading the IFN-immune response by overcoming HDAC6 functions. HDAC6 has emerged as an anti-ZIKV factor by targeting NS5.

Vector-borne diseases (VBD) exert a considerable toll on global health. Vector control strategies efficacy is being threatened by the emergence and spread of insecticide resistance worldwide. In this study, we investigated the insecticide resistance phenotypes and genotypes of Ae. aegypti populations in four regions of Puerto Rico. Insecticide resistance intensity CDC bioassays were employed to determine the response to deltamethrin and malathion. In parallel, next generation targeted amplicon sequencing was used to investigate the presence of insecticide resistance-conferring mutations in nine targets across four genes: the voltage gated sodium channel ( vgsc ); GABA ( rdl ); acetylcholinesterase ( ace-1 ); and Glutathione-S-transferase epsilon 2 ( GSTe2 ). We observed high resistance levels to deltamethrin and malathion in Ae. aegypti , supported by molecular evidence revealing five mutations (V410L ( vgsc ), L978F ( vgsc ), V1012I/R ( vgsc ), F1534C ( vgsc ), A301S ( rdl )), previously linked to insecticide resistance. A new mutation (L921I, vgsc ) was also detected, which has not yet been documented in Aedes spp. vectors but has been linked to pyrethroid resistance in other medically significant vectors and agricultural pests. Our research highlights the presence of insecticide resistance and associated mutations in Puerto Rico, which is valuable for vector control programs, providing information to guide decisions regarding the implementation of effective control interventions. Word Count: 282

Dengue (DENV) virus and Zika virus (ZIKV) are two flaviviruses of major public health concern. One drawback designing effective vaccines is our limited understanding of the mechanisms ruling protection or harm among DENV serotypes, or between DENV and ZIKV. Here, we depleted rhesus macaques of CD4 + T cells in vivo before primary DENV infection and/or secondary ZIKV challenge to recreate a sub-optimal priming of the humoral immune response. Our results support that CD4 + T cells are needed to induce a quantitative and type-specific effective humoral immune response against primary DENV, but also against secondary ZIKV in DENV-experimented subjects. Our results also indicate a limited contribution of the DENV-Memory B cells to anti-ZIKV response. Furthermore, our results suggest that a suboptimal B cell priming during a primary DENV infection does differentially impact different antibody (Abs) properties. While binding or neutralization of ZIKV or DENV during a subsequent exposure to ZIKV is not affected by the lack of CD4 + T - B cells interaction during a primary DENV infection, that interaction is critical to guarantee the Abs specificity. Also, we found that depleting CD4 + T cells before DENV primary infection but not before ZIKV challenge significantly increases Abs cross-reactivity against DENV-EDIII domain and DENV-NS1 protein but not against ZIKV-EDIII domain or NS1 protein. Furthermore, there was more cross-reactivity among the DENV-NS1 proteins than against DENV-EDIII domains, suggesting that during a primary DENV infection CD4 + T cells have a different weight in the responses against EDIII domain and NS1 protein. The proper Abs binding and neutralization with increased cross-reactivity profile was associated with limited frequency of circulating peripheral T helper cells (pTfh) with T helper 1 phenotype (CD4+/CXCR5+/CXCR3+) and expressing markers related to B cell activation (CXCR5+/CXCR3+/PD-1+/ICOS+) in the group depleted of CD4 + T cells only before primary DENV infection. However, memory B cells – but not Antibody Secreting Cells (ASC) activation 7 days after the infection – positively correlate with those two populations of pTfh. Finally, when Abs cross-reactivity values were incorporated in a Principal Component Analysis (PCA), the DENV-CD4 + T depleted group separates from the other two groups with similar Abs binding and neutralization profiles. Our result strongly suggests that during a heterologous sequential DENV/ZIKV infections Abs binding, and neutralization, may be regulated by different factors than their specificity. Before, the induction of cross-neutralizing Abs has been described in the context of secondary DENV infection. Here, for the first time, we are reproducing the experimental conditions leading to the generation of such Abs population in vivo . In summary, we show that suboptimal immune priming during a primary flavivirus infection has functional consequences during a secondary heterologous infection. Finally, we shown that CD8 + T cells are essential to guarantee an optimal Abs neutralization activity. These results have huge implications understanding the immune response to DENV vaccines (and maybe ZIKV), including why an optimal vaccine or natural-induced neutralizing response not necessarily protects or enhances pathogenesis during a subsequent natural heterologous exposure.

Temperature profoundly affects various aspects of ectotherm biology. Notably, in mosquito species that spread viral diseases, temperature influences not only vector biology, but also the dynamics of pathogen-vector interactions. However, research attempting to address the role of the thermal environment in disease transmission often employs constant temperatures, which do not reflect the natural diurnal fluctuations these organisms experience. Additionally, most studies focus on adult mosquitoes in the period following virus infection. Much less attention has been paid to evidence indicating that temperatures experienced during earlier developmental stages may also affect the ability of disease vectors to be infected with and transmit viruses. Here, we show that Aedes aegypti exposed to temperatures below 25 deg C, specifically during the pupal stage of development, exhibit heightened susceptibility to Zika virus (ZIKV), which increases transmission efficiency. Modeling suggests that exposing mosquitoes to cooler fluctuating diurnal temperature ranges only during the relatively short pupal stage increases the R0 or reproductive number of ZIKV. Data loggers placed near Harris County Mosquito Control trap sites consistently recorded temperatures below 25 deg C, indicating natural exposure to such conditions. These results highlight the significance of thermal heterogeneity in the microhabitats where container-breeding mosquitoes undergo development. Such heterogeneity may play a more important role in the transmission of mosquito-borne diseases than previously recognized.

ABSTRACT Nucleic acid tests (NATs) are essential for biomedical diagnostics. Traditional NATs, often complex and expensive, have prompted the exploration of Toehold-Mediated Strand Displacement (TMSD) circuits as an economical alternative. However, the wide application of TMSD-based reactions is limited by ‘leakage’—the spurious activation of the reaction leading to high background signals and false positives. Here we introduce a new TMSD cascade that recognizes a custom nucleic acid input and generates an amplified output. The system is based on a pair of thermodynamically spring-loaded DNA modules. The binding of a predefined nucleic acid target triggers an intermolecular reaction that activates a T7 promoter, leading to the perpetual transcription of a fluorescent aptamer that can be detected by a smartphone camera. The system is designed to permit the selective depletion of leakage byproducts to achieve high sensitivity and zero-background signal in the absence of the correct trigger. Using Zika virus (ZIKV)- and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-derived nucleic acid sequences, we show that the assay generates a reliable target-specific readout. Native RNA can be directly detected under isothermal conditions, without requiring reverse transcription, with a sensitivity as low as 200 attomole. The modularity of the assay allows easy re-programming for the detection of other targets by exchanging a single sequence domain. This work provides a low-complexity and high-fidelity synthetic biology tool for point-of-care diagnostics and for the construction of more complex biomolecular computations.

ABSTRACT Background The international flight network creates multiple routes by which pathogens can quickly spread across the globe. In the early stages of infectious disease outbreaks, analyses using flight passenger data to identify countries at risk of importing the pathogen are common and can help inform disease control efforts. A challenge faced in this modelling is that the latest aviation statistics (referred to as contemporary data) are typically not immediately available. Therefore, flight patterns from a previous year are often used (referred to as historical data). We explored the suitability of historical data for predicting the spatial spread of emerging epidemics. Methods We analysed monthly flight passenger data from the International Air Transport Association to assess how baseline air travel patterns were affected in outbreaks of MERS, Zika, and SARS-CoV-2 over the past decade. We then used a stochastic discrete time SEIR metapopulation model to simulate global spread of different pathogens, comparing how epidemic dynamics differed in simulations based on historical and contemporary data. Results We observed local, short-term disruptions to air travel from South Korea and Brazil for the MERS and Zika outbreaks we studied, whereas global and longer-term flight disruption occurred during the SARS-CoV-2 pandemic. For outbreak events that were accompanied by local, small, and short-term changes in air travel, epidemic models using historical flight data gave similar projections of timing and locations of disease spread as when using contemporary flight data. However, historical data were less reliable to model the spread of an atypical outbreak such as SARS-CoV-2 in which there were durable and extensive levels of global travel disruption. Conclusions The use of historical flight data as a proxy in epidemic models is an acceptable practice except in rare, large epidemics that lead to substantial disruptions to international travel.

Alzheimer’s Disease (AD), a progressive and debilitating condition, is reported to be the most common type of dementia, with at least 55 million people believed to be currently affected. Many causation hypotheses of AD exist, yet the intriguing link between viral infection and its possible contribution to the known etiology of AD has become an attractive focal point of research for the field and a challenging study task. In this review, we will explore the historical perspective and milestones that led the field to investigate the viral connection to AD. Specifically, several viruses such as Herpes Simplex Virus 1 (HSV-1), Zika virus (ZIKV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), along with several others mentioned, include the various viruses presently considered within the field. We delve into the strong evidence implicating these viruses in the development of AD. We will also extend beyond these mere associations by carefully analyzing the potential mechanisms by which viruses may contribute to AD pathology. This includes but is not limited to direct neuronal infections, dysregulation of immune responses, and the impact on protein processing. Controversies and challenges of the viral-AD relationship emerge as we tease out these potential mechanisms considered. Looking forward, we emphasize the future directions the field should take to tackle the remaining unanswered questions and the glaring research gaps that persist. Overall, this review aims to provide a comprehensive survey of the past, present, and future of the potential link between viral infections and their association with AD development.

Abstract Objective: To describe the feeding characteristics and growth of children with prenatal exposure to Zika virus (ZIKV) from birth to 48 months. Design: Using data from the prospective Microcephaly Epidemic Research Group Pediatric Cohort (MERG-PC), children without microcephaly born to mothers with evidence of ZIKV infection during pregnancy (ZIKV-exposed children without microcephaly) and children with Zika-related microcephaly were compared using repeated cross-sectional analyses within the following age strata: birth; 1 to 12; 13 to 24; 25 to 36; and 37 to 48 months. The groups were compared in relation to prematurity, birth weight, breastfeeding, alternative feeding routes, dysphagia and anthropometric profiles based on the World Health Organization Anthro z-scores (weight-length/height, weight-age, length/height-age and BMI-age). Results: The first assessment included 248 children, 77 (31.05%) with microcephaly and 171 (68.95%) without microcephaly. The final assessment was performed on 86 children. Prematurity was 2.35 times higher and low birth weight was 3.49 times higher in children with microcephaly. The frequency of breastfeeding was high (>80%) in both groups. On discharge from the maternity hospital, the frequency of children requiring alternative feeding route in both groups was less than 5%. After 12 months of age, children with microcephaly required alternative feeding route more often than children without microcephaly. In children with microcephaly, the z-score of all growth indicators was lower than in children without microcephaly. Conclusions: Children with Zika-related microcephaly were more frequently premature and low birth weight and remained with nutritional parameters, i.e., weight-for-age, weight-for-length/height and length/height-for-age below those of the children without microcephaly.

Summary Viral glycoproteins drive membrane fusion in enveloped viruses and determine host range, tissue tropism and pathogenesis. Despite their importance, there is a fragmentary understanding of glycoproteins within the Flaviviridae ; for many species the glycoproteins have not yet been identified, for others, such as the hepaciviruses, the molecular mechanisms of membrane fusion remain uncharacterised. Here, we combine comprehensive phylogenetic analyses with systematic protein structure prediction to survey glycoproteins across the entire Flaviviridae . We discover class-II fusion systems, homologous to the orthoflavivirus E glycoprotein, in most species, including highly-divergent jingmenviruses and large genome flaviviruses. However, the E1E2 glycoproteins of the hepaci-, pegi- and pestiviruses are structurally distinct, may represent a novel class of fusion mechanism, and are strictly associated with infection of vertebrate hosts. By mapping glycoprotein distribution onto the underlying phylogeny we reveal a complex history of evolutionary events that have shaped the diverse virology and ecology of the Flaviviridae .

The flavivirus genus includes human pathogenic viruses such as Dengue (DENV), West Nile (WNV) and Zika virus (ZIKV) posing a global health threat due to limited treatment options. Ion channels are crucial for various viral life cycle stages, but their potential as targets for antivirals is often not fully realized due to the lack of selective modulators. Here, we observe that the human endolysosomal cation channel TRPML2 agonist ML2-SA1 impairs the late life cycle stages of ZIKV, thus underscoring TRPML2 as a promising antiviral target. Upon treatment with ML2-SA1, levels of intracellular genomes and number of released virus particles of two different ZIKV isolates were significantly reduced. ML2-SA1-treated cells displayed enlarged vesicular structures and multivesicular bodies with ZIKV envelope protein accumulation. However, no increased ZIKV degradation in lysosomal compartments was observed. Rather, the antiviral effect of ML2-SA1 seemed to manifest by the compound’s negative impact on genome replication. Moreover, ML2-SA1 treatment also led to intracellular cholesterol accumulation. ZIKV as well as many other viruses including the Orthohepevirus Hepatitis E virus (HEV) rely on the endolysosomal system and are affected by intracellular cholesterol levels to complete their life cycle. Since we observed ML2-SA1 to also negatively impact HEV infections in vitro, this compound may harbor a broader antiviral potential through perturbing the intracellular cholesterol distribution. Besides underscoring the potential of TRPML2 as a promising target for combatting viral infections, we uncover a tentative connection between this protein and cholesterol distribution within the context of infectious diseases.

Zika virus is an arthropod-borne virus that transmitted through various mosquito vectors and containing structural and non-structural proteins in their genome assembly. It is an emerging infectious disease causing very serious complications such as Microcephaly in infants and Guillain–Barré syndrome in adults. After analyzing the previous studies, we have targeted the NS2B-NS3 protease that serves as an effective drug target owing to its role in viral replication and immune evasion within the host. The main objective of the study is to find out the best compound(s) against ZIKA virus that can inhibit the transmission cycles as well as the replication process. We have subjected selected 20 Flavonoids from various Origanum species found in the Mediterranean regions and performed pharmacological analysis using SwissADME followed by the Molecular Docking studies using AutoDock Vina 4.0. The best hit compound after docking analysis were subjected to molecular dynamic simulation at 100 ns using Desmond Schrodinger to analyze the stability of molecule. After pharmacological analysis and molecular docking analysis, Isovitexin and Cirsiliol were observed to be best hit compound against NS2B-NS3 complex i.e. (-8.8 kcal/mol and -8.5 kcal/mol). Both the hit compounds were subjected to dynamic studies where they also exposed the better stability with the complex and inhibiting the replicating molecules observed through ligand-protein contacts. In the present study, we recommend both the hit compounds for in vitro and in vivo study for further investigation with respect to ZIKA virus.

We investigated the interaction between the insect-specific virus, Piura virus (PIUV) and the arbovirus Zika virus (ZIKV) in Aedes albopictus cells. We performed coinfection experiments in C6/36 cells. Piura virus (Cor 33 strain, Colombia) and ZIKV (PRVABC58 strain, Puerto Rico) were co-inoculated into C6/36 cells using two MOI combinations: 0.1 for both viruses and 1.0 for ZIKV, 0.1 for PIUV. Wells were infected in triplicate with either PIUV and ZIKV coinfection, ZIKV-only, or PIUV-only. Mock infected cells served as control wells. The cell suspension was collected daily through 7 days post-infection. Zika virus load was titrated by TCID50 on Vero 76 cells. The ZIKV-only infection and PIUV and ZIKV coinfection experiments were also quantified by RT-qPCR. We also investigated whether ZIKV interfered in the PIUV replication. PIUV suppressed the replication of ZIKV resulting in a 10,000-fold reduction in ZIKV titers within 3 days post-infection. PIUV viral loads were not reduced in the presence of ZIKV. We conclude that, when concurrently infected, PIUV suppresses ZIKV in C6/36 cells while ZIKV does not interfere in PIUV replication.

This scoping review explored the impact of disasters on contraception in high-income countries. Comprehensive searches were conducted and extracted data analysed thematically. 110 articles were included. The majority focused on the Zika virus outbreak and the COVID-19 pandemic. Four key themes were identified: importance of contraception during disasters, impact of disasters on contraceptive behaviour, barriers to contraception during disasters and ways of improving uptake of contraception during disasters. Despite efforts to increase access to contraception, barriers to uptake meant unmet need persisted. To prevent adverse health outcomes and reduce health costs, efforts to remove barriers to uptake should be intensified.

Zoonotic viruses, such as coronaviruses, the Ebola virus, the Zika virus, Nipah, Laasa, and rabies, can be transmitted from animals to humans (1). There is a need to develop inhibitors because they can potentially prevent or treat viral infections in humans and animals (2). Metadichol® is a nanoemulsion of long-chain alcohols that is a potent inhibitor of viruses. We present the results of in vitro assays showing that it inhibits Lassa, rabies, and Nipah viruses at concentrations ranging from 0.8 to 2.6 µg/ml. It is likely that the binding of metadichol to VDR (vitamin D receptor) leads to the regulation of c-MYC ( MYC Proto-Oncogene, BHLH Transcription Factor), which controls the expression of SP1 (SP1 transcription factor), which is the key step in controlling the viral replication gene GSPT1 ( G1 to S Phase Transition 1). Since metadichol is commercially available and nontoxic, with an LD50 of more than 5000 mg/kg in rats, it could be useful in the treatment of such zoonotic diseases.

ABSTRACT Infection of pregnant women by Zika virus (ZIKV) is associated with severe neurodevelopmental defects in newborns through poorly defined mechanisms. Here, we engineered a zebrafish in vivo model of ZIKV infection to circumvent limitations of existing mammalian models. Leveraging the unique tractability of this system, we gained unprecedented access to the ZIKV-infected brain at early developmental stages. The infection of zebrafish larvae with ZIKV phenocopied the disease in mammals including a reduced head area and neural progenitor cells (NPC) infection and depletion. Moreover, transcriptomic analyses of ZIKV-infected NPCs revealed a distinct dysregulation of genes involved in survival and neuronal differentiation, including downregulation of the expression of the glutamate transporter vglut1 , resulting in an altered glutamatergic network in the brain. Mechanistically, ectopic expression of ZIKV protein NS4A in the larvae recapitulated the morphological defects observed in infected animals, identifying NS4A as a key determinant of neurovirulence and a promising antiviral target for developing therapies.

ABSTRACT Background Tick-borne encephalitis (TBE) virus is the most common tick-transmitted Orthoflavivirus in Europe. Due to its non-specific symptoms, TBE is primarily diagnosed by ELISA-based detection of specific antibodies in the patient serum. However, cross-reactivity between orthoflaviviruses complicates the diagnosis. Specificity problems may be overcome by serum neutralization assays (SNT), however clinically relevant orthoflaviviruses require handling in biosafety level 3 (BSL-3) and they have highly divergent viral kinetics and cell tropisms. Methods We present a reporter viral particle (RVP) based SNT in which the infectivity is measured by luminescence and that can be performed under BSL-2 conditions. Findings The RVP-based SNT for TBEV exhibited a remarkable correlation with the traditional virus-based SNT (R2=0.8614, p<0.0001). Notably, the RVP-based assay demonstrated a sensitivity of 91.7% (95% CI: 87.2-97.1%) and specificity of 100% (95% CI: 79.6-100%). We also tested the cross-reactivity of serum samples in RVP-based assays against other orthoflaviviruses (yellow fever virus, dengue virus type 2, Zika virus, West Nile virus and Japanese encephalitis virus). Interestingly, in 90% of cases where a serum sample had tested TBEV-positive by ELISA but negative by RVP-based SNT, we identified antibodies against other orthoflaviviruses. Interpretations The RVP-based seroneutralization assay show clinical relevance and broad- applicability. Funding This study was supported by Bavarian Nordic grant to R.A. and V.C. RESEARCH IN CONTEXT Evidence before this study ELISA tests for orthoflavivirus serology are the method of choice in all diagnostic laboratories despite the cross-reactivity issues. Although seroneutralization testing (SNT) provides more reliable results, it requires BSL-3 conditions and approximately a week to obtain the results. However, developing tests with a broader applicability could overcome the problem of cross-reactivity of antibodies against flaviviruses could be overcome leading to a more accurate diagnosis and fewer non-useful results. Although alternative serological tests for other orthoflaviviruses have been investigated they have limitations, including lack of uniformity for different orthoflaviviruses, the need for a BSL-3 laboratory to perform them, and results taking 4-5 days. The reporter viral particle system (RVP) we used in this study has been reported for all orthoflaviviruses, except for YFV. However, its applicability has not been tested in comparison to traditional methods with clinical samples. Added value of this study We tested the RVP system uniformly for different orthoflaviviruses and evaluated the sensitivity and specificity of SNT based on RVP compared to virus-based and to ELISA. Additionally, we found that false positives in ELISA in our clinical samples are frequently related to YFV positive samples. Implications of all the available evidence This study demonstrates the reliability and broad applicability of implementing RVP-based SNT in a clinical setting. This test can overcome the issues of false positive results from ELISA tests. Additionally, our data suggest that it is important to consider YFV exposure or vaccination anamnesis in patient’s medical history. This is consistent with the phylogenetic similarity between YFV and TBEV if compared to other flaviviruses.

Zika virus (ZIKV) causes human testicular inflammation and alterations in sperm parameters and causes testicular damage in mouse models. The involvement of individual immune cells in testicular damage is not fully understood. We detected virus in the testes of the interferon (IFN) α/β receptor -/- A129 mice three weeks post-infection and found elevated chemokines in the testes, suggesting chronic inflammation and long-term infection play a role in testicular damage. In the testes, myeloid cells and CD4 + T cells were absent at 7 dpi but were present at 23 days post-infection (dpi), and CD8 + T cell infiltration started at 7 dpi. CD8 -/- mice with an antibody-depleted IFN response had a significant reduction in spermatogenesis, indicating that CD8 + T cells are essential to prevent testicular damage during long-term ZIKV infections. Our findings on the dynamics of testicular immune cells and importance of CD8 + T cells functions as a framework to understand mechanisms underlying observed inflammation and sperm alterations in humans.

Summary Zika virus (ZIKV) is a mosquito-borne flavivirus that caused an epidemic in the Americas in 2016 and is linked to severe neonatal birth defects, including microcephaly and spontaneous abortion. To better understand the host response to ZIKV infection, we adapted the 10x Genomics Chromium single cell RNA sequencing (scRNA-seq) assay to simultaneously capture viral RNA and host mRNA. Using this assay, we profiled the antiviral landscape in a population of human moDCs infected with ZIKV at the single cell level. The bystander cells, which lacked detectable viral RNA, expressed an antiviral state that was enriched for genes coinciding predominantly with a type I interferon (IFN) response. Within the infected cells, viral RNA negatively correlated with type I IFN dependent and independent genes (antiviral module). We modeled the ZIKV specific antiviral state at the protein level leveraging experimentally derived protein-interaction data. We identified a highly interconnected network between the antiviral module and other host proteins. In this work, we propose a new paradigm for evaluating the antiviral response to a specific virus, combining an unbiased list of genes that highly correlate with viral RNA on a per cell basis with experimental protein interaction data. Our ZIKV-inclusive scRNA-seq assay will serve as a useful tool to gaining greater insight into the host response to ZIKV and can be applied more broadly to the flavivirus field.

As climate change alters Earth’s biomes, it is expected the transmission dynamics of mosquito-borne viruses will change. While the effects of temperature changes on mosquito-virus interactions and spread of the pathogens have been elucidated over the last decade, the effects of relative humidity changes are still relatively unknown. To overcome this knowledge gap, we exposed Ae. aegypti females to various low humidity conditions and measured different components of vectorial capacity such as survival, blood-feeding rates, and changes in infection and dissemination of Zika virus. Survival decreased as the humidity level decreased, while infection rates increased as the humidity level decreased. Alternatively, blood feeding rates and dissemination rates peaked at the intermediate humidity level, but returned to the levels of the control at the lowest humidity treatment. These results provide empirical evidence that Ae. aegypti exposure to low humidity can enhance Zika virus infection in the mosquito, which has important implications in predicting how climate change will impact mosquito-borne viruses.