Background The paucity of data on the contemporary causes of serious infection among the world’s most vulnerable children means the landscape of emerging paediatric infectious disease remains largely undefined and out of focus on the global vaccine research and development agenda. Methods We aimed to partially define the paediatric infectious disease landscape in a typical low-income setting in sub-Saharan Africa in Kilifi, Kenya by simultaneously estimating antibody prevalence for 38 infectious diseases using a longitudinal birth cohort that was sampled between 2002 and 2008 and a paediatric inpatient cohort that was sampled between 2006 and 2017. Findings Among the infectious diseases with the highest antibody prevalence in the first year of life were vaccine-preventable diseases such as RSV (57.4%), mumps (31.5%) and influenza H3N2 (37.3%). Antibody prevalence for Plasmodium falciparum shifted substantially over time, from 47% in the mid 2000s to 13% approximately 10 years later corresponding to a documented decline in parasite transmission. A high prevalence of antibodies was also observed in the first year of life for infections for which no licenced vaccines are currently available, including norovirus (34.2%), cytomegalovirus (44.7%), EBV (29.3%) and coxsackie B virus (40.7%). The prevalence to antibodies to vaccine antigens in the local immunisation schedule was generally high but varied by antigen. Interpretation The data show a high and temporally stable infection burden of RSV, mumps and influenza, providing a compelling evidence base to support progress towards the introduction of these vaccines into the local immunization schedule. The high prevalence of norovirus, EBV, CMV and Coxsackie B provide rationale for increased vaccine research and development investment. Funding This research was funded by the Wellcome Trust (grant no. WT105882MA).

ABSTRACT In the last decades, many efforts have been put forward in search of inhibitors/drugs specific to ZIKV-infected patients. These inhibitors include approved drugs, natural products, nucleosides, small molecules, and many others to inhibit Zika virus replication in cell and mouse models. In this regard, natural product curcumin has been widely explored in various disease conditions and found to have inhibition potential against ZIKV replication as well. Further, we investigated its inhibitory ability against the ZIKV NS3 helicase. We found that the curcumin interacts with the NS3 helicase domain by forming stable contacts at NTPase and RNA binding sites during molecular dynamic simulation. Furthermore, curcumin inhibits NTPase activity of NS3 helicase with an IC 50 of 64.42 μM. Altogether, the mechanistic insight into the action of curcumin will enlighten further drug discovery research in finding novel molecules.

ABSTRACT Background The microbial communities residing in the mosquito midgut play a key role in determining the outcome of mosquito pathogen infection. Elizabethkingia anophelis , originally isolated from the midgut of Anopheles gambiae , has drawn much attention due to its close association with Aedes and Anopheles mosquitoes, primary vectors of dengue virus and malaria parasites, respectively. E. anophelis possesses a broad-spectrum antiviral phenotype, yet a gap in knowledge regarding the mechanistic basis of its interaction with viruses exists. Methodology/Principal findings To further understand the antiviral interactions between E. anophelis and Zika virus (ZIKV), we utilized a non-targeted multi-omics approach, analyzing lipids, proteins, and metabolites of cell monolayers co-infected with ZIKV and E. anophelis . We further assessed the gene expression of ZIKV when cultured in the presence of E. anophelis . ZIKV cultured in the presence of E. anophelis resulted in an attenuated replicative fitness and unproductive virus infection. Further, in this treatment, we observed lower levels of the nonstructural protein 5 (NS5) and RNA-directed RNA polymerase (RdRp) protein. Lastly, a significant decrease in arginine levels, an essential requirement for viral replication and progression of viral infection was observed. Conclusions/Significance This study provides insights into the molecular basis of E. anophelis antiviral phenotype. These findings improve our knowledge of how microbes and viruses interact to impact viral replication. In the future, our findings can be utilized to unravel the mechanism behind the antiviral phenotype of E. anophelis, and this can help develop novel paradigms for viral therapeutics. AUTHOR SUMMARY Zika is a re-emerging disease and is endemic in many regions of sub-Saharan Africa, Asia and Latin America. It remains a major public health threat and lacks FDA-approved therapeutics or vaccines, hence the urgent need for the identification of alternative approaches that limit the transmission of the pathogens by its primary vector, Aedes spp. The microbial communities residing in the mosquito midgut play a key role in determining the outcome of mosquito pathogen infection. Flavobacteria dominates the mosquito midgut including Elizabethkingia , which is a gram-negative bacillus prevalent in Aedes and Anopheles species of mosquitoes. E. anophelis , a poorly studied midgut microbe, has a broad-spectrum antiviral phenotype, yet the mechanism of its antiviral action is unknown. In this study, we have identified several pathways as well as Zika virus proteins perturbed when the Zika virus is cultivated in the presence of E. anophelis . Our findings do not only provide insights into microbial, virus interaction but could be harnessed to develop novel antiviral tools.

Introduction Providing accurate, evidence-based information to women with Zika infection during pregnancy was problematic because of the high degree of uncertainty in the diagnosis of the infection and the associated risk. The 2015-17 Zika virus epidemic overwhelmingly affected women in countries with limited access to safe abortion. Understanding women’s perspectives on risk communication during pregnancy in the context of an emerging pathogen can help inform risk communication in response to future outbreaks that affect fetal or child development. Methods We conducted a cross-sectional qualitative interview study with 73 women from 7 locations in Brazil, Colombia, and Puerto Rico to understand women’s experiences of ZIKV test and outcome-related communication during the ZIKV pandemic. We used thematic analysis to analyze the in-depth interviews. Findings Participants in Brazil and Colombia reported that the healthcare system’s lack of preparation and organization in communicating ZIKV test results and associated adverse outcomes led to their feeling abandoned and alone in confronting the challenges of a ZIKV-affected pregnancy. In contrast, participants in Puerto Rico reported that the regular testing schedules and clear, well-planned communication between the care team and between providers and pregnant women helped them to feel they could prepare for a ZIKV-affected pregnancy. Conclusion Communication of the risk associated with an emerging pathogen suspected to affect pregnancy and developmental outcomes is a fraught issue. Public health authorities and healthcare providers should work together in the interpandemic period to understand families’ preferences for risk communication during pregnancy in the presence of uncertainty and develop a community-informed plan for risk communication.

Elevated interleukin (IL-)6 levels during prenatal development have been linked to increased risk for neurodevelopmental disorders (NDD) in the offspring, but the mechanism remains unclear. Human-induced pluripotent stem cell (hiPSC) models offer a valuable tool to study the effects of IL-6 on features relevant for human neurodevelopment in vitro . We previously reported that hiPSC-derived microglia-like cells (MGLs) respond to IL-6, but neural progenitor cells (NPCs) in monoculture do not. Therefore, we investigated whether co-culturing hiPSC-derived MGLs with NPCs would trigger a cellular response to IL-6 stimulation via secreted factors from the MGLs. Using N=4 donor lines without psychiatric diagnosis, we first confirmed that NPCs can respond to IL-6 through trans-signalling when recombinant IL-6Ra is present, and that this response is dose-dependent. MGLs secreted soluble IL-6R, but at lower levels than found in vivo and below that needed to activate trans-signalling in NPCs. Whilst transcriptomic and secretome analysis confirmed that MGLs undergo substantial transcriptomic changes after IL-6 exposure and subsequently secrete a cytokine milieu, NPCs in co-culture with MGLs exhibited a minimal transcriptional response. Furthermore, there were no significant cell fate-acquisition changes when differentiated into post-mitotic cultures, nor alterations in synaptic densities in mature neurons. These findings highlight the need to investigate if trans-IL-6 signalling to NPCs is a relevant disease mechanism linking prenatal IL-6 exposure to increased risk for psychiatric disorders. Moreover, our findings underscore the importance of establishing more complex in vitro human models with diverse cell types, which may show cell-specific responses to microglia-released cytokines to fully understand how IL-6 exposure may influence human neurodevelopment.

Accurately estimating the effective reproduction number (Rt) of a circulating pathogen is a fundamental challenge in the study of infectious disease. The fields of epidemiology and pathogen phylodynamics both share this goal, but to date, methodologies and data employed by each remain largely distinct. Here we present EpiFusion: a joint approach that can be used to harness the complementary strengths of each field to improve estimation of outbreak dynamics for large and poorly sampled epidemics, such as arboviral or respiratory outbreaks, and validate it for retrospective analysis. We propose a model of Rt that estimates outbreak trajectories conditional upon both phylodynamic (time-scaled trees estimated from genetic sequences) and epidemiological (case incidence) data. We simulate stochastic outbreak trajectories that are weighted according to epidemiological and phylodynamic observation models and fit using particle Markov Chain Monte Carlo. To assess performance, we test EpiFusion on simulated outbreaks in which transmission and/or surveillance rapidly changes and find that using EpiFusion to combine epidemiological and phylodynamic data maintains accuracy and increases certainty in trajectory and Rt estimates, compared to when each data type is used alone. Finally, we benchmark EpiFusion’s performance against existing methods to estimate Rt and demonstrate advances in efficiency and accuracy. Importantly, our approach scales efficiently with dataset size, including the use of phylogenetic trees generated from large genomic datasets. EpiFusion is designed to accommodate future extensions that will improve its utility, such as introduction of population structure, accommodations for phylogenetic uncertainty, and the ability to weight the contributions of genomic or case incidence to the inference. Author Summary Understanding infectious disease spread is fundamental to protecting public health, but can be challenging as disease spread is a phenomenon that cannot be directly observed. So, epidemiologists use data in conjunction with mathematical models to estimate disease dynamics. Often, combinations of different models and data can be used to answer the same questions – for example ‘traditional’ epidemiology commonly uses case incidence data (the number of people who have tested positive for a disease at a certain time) whereas phylodynamic models use pathogen genomic sequence data and our knowledge of their evolution to model disease population dynamics. Each of these approaches have strengths and limitations, and data of each type can be sparse or biased, particularly in rapidly developing outbreaks or lower-middle income countries. An increasing number of approaches attempt to fix this problem by incorporating diverse concepts and data types together in their models. We aim to contribute to this movement by introducing EpiFusion, a modelling framework that makes improvements on efficiency and temporal resolution. EpiFusion uses particle filtering to simulate epidemic trajectories over time and weight their likelihood according to both case incidence data and a phylogenetic tree using separate observation models, resulting in the inference of trajectories in agreement with both sets of data. Improvements in our ability to accurately and confidently model pathogen spread help us to respond to infectious disease outbreaks and improve public health.

African populations of the mosquito Aedes aegypti are usually considered less susceptible to infection by human-pathogenic flaviviruses than globally invasive populations found outside Africa. Although this contrast has been well documented for Zika virus (ZIKV), it is unclear to what extent it is true for dengue virus (DENV), the most prevalent flavivirus of humans. Addressing this question is complicated by substantial genetic diversity among DENV strains, most notably in the form of four genetic types (DENV1 to DENV4), that can lead to genetically specific interactions with mosquito populations. Here, we carried out a continent-wide survey of DENV susceptibility using a panel of field-derived Ae. aegypti colonies from across the African range of the species and a colony from Guadeloupe, French West Indies as non-African reference. We found considerable variation in the ability of African Ae. aegypti populations to acquire and replicate a panel of six DENV strains spanning the four DENV types. Although African Ae. aegypti populations were generally less susceptible than the reference non-African population from Guadeloupe, in several instances some African populations were equally or more susceptible than the Guadeloupe population. Moreover, the relative level of susceptibility between African mosquito populations depended on the DENV strain, indicating genetically specific interactions. We conclude that unlike ZIKV susceptibility, there is no clear-cut dichotomy in DENV susceptibility between African and non-African Ae. aegypti . DENV susceptibility of African Ae. aegypti populations is highly heterogeneous and largely governed by the specific pairing of mosquito population and DENV strain. Author summary African populations of the mosquito Aedes aegypti are usually thought to be less likely to get infected by flaviviruses compared to Ae. aegypti mosquitoes found outside Africa. While this has been well-demonstrated for Zika virus, it is not clear if the same is true for dengue virus, which is the most common flavivirus in humans. Studying this is complicated by the strain diversity of dengue virus, including four main genetic types, potentially causing different interactions. In this study, we compared several mosquito populations and found that, in general, African mosquitoes were less likely to get infected by dengue virus compared to mosquitoes from outside Africa. However, in some cases, African mosquitoes were just as or even more likely to get infected. The specific strain of dengue virus also influenced how likely African mosquitoes were to get infected, showing that the relationship between African mosquitoes and dengue virus is complex.

The escalation of antibiotic resistance, pandemics, and nosocomial infections underscores the importance of research in both animal and human infectious diseases. Recent advancements in three-dimensional tissue cultures, or "organoids," have revolutionized the development of in vitro models for infectious diseases. Our study conducts a bibliometric analysis on the use of organoids in modeling infectious diseases, offering an in-depth overview of this field's current landscape. We examined scientific contributions from 2009 onward that focused on organoids in host‒pathogen interactions using the Web of Science Core Collection. Our analysis included temporal trends, reference aging, author and institutional productivity, collaborative networks, citation metrics, and keyword cluster dynamics. VOSviewer and CiteSpace facilitated this analytical assessment. The findings reveal significant growth and advancements in organoid-based infectious disease research. Analysis of keywords and impactful publications identified three distinct developmental phases in this area that were significantly influenced by outbreaks of Zika virus and SARS-CoV-2. Hans Clevers and his team are prominent within the author and institutional collaboration networks. The research also highlights the synergistic efforts between academia and publishers in tackling global pandemic challenges. Organoids are proving to be a promising tool in infectious disease research. Their integration into the field necessitates methodological refinements for better physiological emulation and the establishment of extensive organoid biobanks. These improvements are crucial for fully harnessing the potential of organoids in understanding infectious diseases and advancing the development of targeted treatments and vaccines.

SUMMARY Zika virus (ZIKV) infection causes significant human disease that, with no approved treatment or vaccine, constitutes a major public health concern. Its life cycle entirely relies on the cytoplasmic fate of the viral RNA genome (vRNA) through a fine-tuned equilibrium between vRNA translation, replication and packaging into new virions, all within virus-induced replication organelles (vRO). In this study, with an RNAi mini-screening and subsequent functional characterization, we have identified insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) as a new host dependency factor that regulates vRNA synthesis. In infected cells, IGF2BP2 associates with viral NS5 polymerase and redistributes to the perinuclear viral replication compartment. Combined fluorescence in situ hybridization-based confocal imaging, in vitro binding assays, and immunoprecipitation coupled to RT-qPCR, showed that IGF2BP2 directly interacts with ZIKV vRNA 3’-nontranslated region. Using ZIKV sub-genomic replicons and a replication-independent vRO induction system, we demonstrated that IGF2BP2 knockdown impairs de novo viral organelle biogenesis and, consistently, vRNA synthesis. Finally, the analysis of immunopurified IGF2BP2 complex using quantitative mass spectrometry and RT-qPCR, revealed that ZIKV infection alters the protein and RNA interactomes of IGF2BP2. Altogether, our data support that ZIKV hijacks and remodels the IGF2BP2 ribonucleoprotein complex to regulate vRO biogenesis and vRNA neosynthesis.

Abstract Zika virus (ZIKV) infection continues to pose a significant public health concern due to limited available preventive measures and treatments. ZIKV is unique among flaviviruses in its vertical transmission capacity (i.e., transmission from mother to fetus) yet the underlying mechanisms remain incompletely understood. Here, we show that both African and Asian lineages of ZIKV induce tunneling nanotubes (TNTs) in placental trophoblasts and multiple other mammalian cell types. Amongst investigated flaviviruses, only ZIKV strains trigger TNTs. We show that ZIKV-induced TNTs facilitate transfer of viral particles, proteins, and RNA to neighboring uninfected cells. ZIKV TNT formation is driven exclusively via its non-structural protein 1 (NS1); specifically, the N-terminal region (50 aa) of membrane-bound NS1 is necessary and sufficient for triggering TNT formation in host cells. Using affinity purification-mass spectrometry of cells infected with wild-type NS1 or non-TNT forming NS1 (pNS1ΔTNT) proteins, we found mitochondrial proteins are dominant NS1-interacting partners, consistent with the elevated mitochondrial mass we observed in infected trophoblasts. We demonstrate that mitochondria are siphoned via TNTs from healthy to ZIKV-infected cells, both homotypically and heterotypically, and inhibition of mitochondrial respiration reduced viral replication in trophoblast cells. Finally, ZIKV strains lacking TNT capabilities due to mutant NS1 elicited a robust antiviral IFN-λ 1/2/3 response, indicating ZIKV's TNT-mediated trafficking also allows ZIKV cell-cell transmission that is camouflaged from host defenses. Together, our findings identify a new stealth mechanism that ZIKV employs for intercellular spread among placental trophoblasts, evasion of antiviral interferon response, and the hijacking of mitochondria to augment its propagation and survival. Discerning the mechanisms of ZIKV intercellular strategies offers a basis for novel therapeutic developments targeting these interactions to limit its dissemination.

ABSTRACT Infection with any of the four dengue virus serotypes (DENV1-4) can protect against or enhance subsequent dengue depending on pre-existing antibodies and the subsequent infecting serotype. Additionally, primary infection with the related flavivirus Zika virus (ZIKV) has been shown to increase DENV2 disease. Here, we measured how prior DENV and ZIKV immunity influenced risk of disease caused by all four serotypes in a pediatric Nicaraguan cohort. Of 3,412 participants in 2022, 10.6% experienced symptomatic DENV infections caused by DENV1 (n=139), DENV4 (n=133), DENV3 (n=54), DENV2 (n=9), or an undetermined serotype (n=39). Longitudinal clinical and serological data were used to define infection histories, and generalized linear and additive models adjusted for age, sex, time since the last infection, cohort year, and repeat measurements were used to predict disease risk. Compared to flavivirus-naïve participants, primary ZIKV infection increased disease risk of DENV4 (relative risk = 2.62, 95% confidence interval: 1.48-4.63) and DENV3 (2.90, 1.34-6.27) but not DENV1 (1.20, 0.72-1.99). Primary DENV infection or a DENV followed by ZIKV infection also increased DENV4 risk. We re-analyzed 19 years of cohort data and demonstrated that prior flavivirus-immunity and pre- existing antibody titer differentially affected disease risk for incoming serotypes, increasing risk of DENV2 and DENV4, protecting against DENV1, and protecting at high titers but enhancing at low titers against DENV3. We thus find that prior ZIKV infection, like prior DENV infection, increases risk of certain DENV serotypes. Cross-reactivity among flaviviruses should be carefully considered when assessing vaccine safety and efficacy. One-Sentence Summary Dengue disease risk is differentially modulated depending on pre- existing immunity to dengue and Zika virus infections and the secondary infecting serotype.

Co-circulation of diseases is a public health concern phenomenon as it often informs of population cross-exposure, susceptibility, and cross-protection dynamics. While it commonly occurs, spatial analysis predominately focuses on understanding the individual character of the involved diseases, often neglecting any contributions of co-circulating conditions. This study explores the spatial dynamics and interactions among Zika virus (ZIKV), Dengue virus (DENV), and Chikungunya virus (CHIKV) within the context of co-circulation in the Andean region of Colombia, a tropical and subtropical area highly affected by mosquito-borne diseases. We used Poisson cokriging, a geostatistical method tailored to handle count data (cases), account for the heterogeneous distribution of the population and integrate auxiliary information in the form of count variables. Our results show that Poisson cokriging effectively mitigates the impact of highly variable population densities in the Andean region, producing refined and denoised risk estimates. Likewise, by incorporating information from co-infection, we improved the individual risk estimates and refined the identification of high-risk areas. Our findings show that disease hotspots primarily emerge in municipalities characterized by high rates of co-circulation, coupled with suboptimal water coverage, hygiene conditions, and crowded living environments. We anticipate that the outcomes of this study will contribute to a better understanding of disease co-circulation. In the context of the mosquito-borne disease syndemics in the Andean region, it may offer insights for evidence-based public health strategies.

The current study analyzes the Zika virus from Asia from a phylogenomic and phylodynamic perspective. To perform this study, 68 genomes from Asia were analyzed. A similar dataset was used to perform phylogenomics using Median Joining Network (MJN). MJN reconfirms African origin of Zika virus along with few notable instances of common origin of infection in some Asian countries. We investigated population dynamics using SkyGrid, Exponential Growth, and Constant Coalescence models. According to our phylodynamic analysis, effective population sizes throughout Asia reached higher peaks during the outbreak of 2016-2017. Zika virus population size increased exponentially during 2016-2017. From 1966 to 2021, there was a high and low peak in effective population size except for the outbreak of 2016-2017. To counter the outbreak of Zika Virus in Asian Countries in future, we recommend continuous genomic surveillance.

Abstract With the recent emergence of the coronavirus pandemic, the scare for other viral pandemics is on the rise. Already having caused an epidemic in 2015-16, Zika virus (ZIKV) poses a threat for potential havoc. Thus, there is an urgent need to produce drugs and vaccines for the same as no approved vaccinations exist for the virus as of now. With the optimization of codon usage, the process of vaccine development can be accelerated and efficacy can be ensured. ZIKV genome has 3 structural genes (envelope, capsid and membrane which is obtained from pre membrane) and 7 nonstructural genes (NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5). We have used these 10 genes in 5 different strains of ZIKV for in silico DNA optimization in Escherichia coli. The mean CAI, GC% and AT% of wild-type DNA and optimized DNA of each were compared. It was observed that the CAI and GC% had increased in optimized DNA as compared to wild- type while the opposite was seen for AT%. The results show that codon optimization helps in efficient expression of proteins in the host. These could be used in the development of biotherapeutics. The ideal genes to be overexpressed in development of biotherapeutics are the membrane precursor (prM) and envelope (E) genes as the results have shown.

Zika Virus (ZIKV) is a pathogenic member of the flavivirus family, with several unique charac-teristics. Unlike any other arbovirus, ZIKV can be transmitted sexually and maternally, and thus produce congenital syndromes (CZS) due to its neurotropism. This challenges the search for safe active molecules that can protect pregnant women and their fetuses. In this context, and in the ab-sence of any existing treatment, it seemed worthwhile to test whether the known cytoprotective properties of adiponectin and its pharmacological analog, AdipoRon, could influence the outcome of ZIKV infection. We showed that both AdipoRon and adiponectin could significantly reduce in vitro infection of A549 epithelial cells, a well-known cell model for flaviviruses infection studies. This effect was particularly observed when a pre-treatment was carried out. Conversely, ZIKV revealed an ability to down-regulate adiponectin receptor expression and thereby limit adi-ponectin signaling.

Mosquitoes, particularly Aedes aegypti , are critical vectors for globally significant pathogenic viruses. This study examines the limitations of oral RNA interference (RNAi) as a strategy to disrupt viral transmission by Ae. aegypti . We hypothesized that double-stranded RNA (dsRNA) targeting the Zika virus (ZIKV) or chikungunya virus (CHIKV) genomes produced by engineered bacterial symbionts could trigger an antiviral response. Mosquitoes mono-colonized with Escherichia coli producing dsZIK or dsCHIK did not display reduced viral titers following exposure to virus-contaminated bloodmeals and failed to generate dsZIK- or dsCHIK-derived small interfering RNAs. To address potential limitations of bacterial dsRNA release, we explored dsRNA inoculation via feeding and injection. While viral replication was impeded in mosquitoes injected with dsZIK or dsCHIK, no antiviral effect was observed in dsRNA-fed mosquitoes. These findings highlight complexities of implementing oral RNAi as an antiviral strategy in Ae. aegypti and warrant further exploration of local and systemic RNAi mechanisms.

Flaviviruses are a group of positive sense single-stranded RNA viruses predominantly transmitted by arthropods (mainly mos-quitoes), that cause severe endemic infections and epidemics on a global scale. It represents a major cause of systemic morbidity and death that are expanding worldwide. Among this group, Dengue fever, West Nile virus, Yellow Fever, Japanese Encephalitis, and recently Zika virus have been linked to a spectrum of ocular manifestations. The latter encompass subconjunctival hemor-rhage and conjunctivitis, anterior and posterior uveitis (inclusive of vitritis, chorioretinitis, and retinal vasculitis), maculopathy, retinal hemorrhages, and optic neuritis. Clinical diagnosis of these infectious diseases is primarily based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular involvement. Diagnosis confirmation relies on laboratory testing, including RT-PCR and serological testing. Ocular involvement typically follows a self-limited course but can result in irreversible visual impairment. Effective treatment for flavivirus infections is currently unavailable. Prevention remains the mainstay for arthropod vector and zoonotic disease control. Effective vaccines are available only for Yellow Fever virus, Dengue virus and Japanese Encephalitis virus. This review comprehensively summarizes the current knowledge regarding the ophthalmic mani-festations of the foremost flavivirus-associated human diseases.

The progressive reappearance of the Zika virus (ZIKV) infection since October 2013 and its circulation in >70 countries and territories (from French Polynesia to Brazil and other countries in the Americas, with sporadic spread in Europe and the East) has long been reported as a global public health emergency. ZIKV is a virus transmitted by arthropods (arboviruses), mainly by Aedes mosquitoes. ZIKV can also be transmitted to humans through mechanisms other than vector infection such as sexual intercourse, blood transfusions, mother-to-child transmission. The latter mode of transmission can give rise to a severe clinical form called Congenital Zika Syndrome (CZS) which can result in spontaneous abortion or serious pathological alterations in the fetus such as microcephaly, neurological and orofacial anomalies. In this study, beside a succinct overview of the etiological, microbiological, epidemiological aspects and modes of transmission of Zika virus infection, we have focused our attention on the pathogenetic and histopathological aspects in pregnancy and the pathogenetic and molecular mechanisms that can determine microcephaly, and consequently the clinical alterations, typical of the fetus and newborns, in a subject affected by CZS.

Emerging infectious diseases (EIDs) continue to be a problem all across the world, but in certain areas the threat is greater than in others. The detection of new diseases will aid in the focus of surveillance efforts. Specifically, identifying a "patient zero" is critical step to help limit further transmission. In fact, several factors have been found to contribute to emerging infectious diseases emergence and transmission. Antigenic drift is an important factor that affects vaccine effectiveness and it is important for scientists and healthcare providers alike to understand how this process works in order to ensure that people receive effective vaccinations against infectious diseases. However, recent advances in biotechnology, immunology and artificial intelligence have enabled us to make progress in diagnosis, treatment, prevention and control of infectious diseases. The fight against infectious diseases will always be ongoing, but the advancement of bioscience offers a promising outlook for the near future. In the last two decades, several high impact zoonotic disease outbreaks have been linked to bat-borne viruses. These include SARS coronavirus, Hendra virus and Nipah virus. In addition, it has been suspected that ebolaviruses and MERS coronavirus are also linked to bats. It is being increasingly accepted that bats are potential reservoirs of a large number of known and unknown viruses, many of which could spillover into animal and human populations. In this article, we discuss the potential risk factors that contribute in emerging infectious diseases. Also, we discuss the management of disease prevention and control.

Summary Background Arboviral diseases, transmitted by infected arthropods, pose significant economic and societal threats. Their global distribution and prevalence have increased in recent years, driven by factors such as climate change, biodiversity loss and urbanization. These diseases are often underestimated due to uneven surveillance and asymptomatic cases. Current surveillance relies on monitoring vector occurrence and spatial distribution, as well as syndromic monitoring. In this work, we aimed to explore the utility of wastewater-based surveillance as an additional, added-value tool for vector-borne viruses tracking. Methods A retrospective wastewater-based surveillance survey was conducted at ten wastewater treatment plants covering a large part of Portugal mainland (North, Lisboa and Vale do Tejo and South regions). Using RT-qPCR, we quantified the RNA concentrations of Dengue (DENV) and Chikungunya (CHIKV) viruses for a period of 12 months ( n = 273 raw wastewater samples), ranging May 2022 - April 2023. Findings DENV was detected in 25% of the samples, with concentrations spanning from 3·5 to 6·8 log copies/L. CHIKV was detectable in 11% of the samples, with concentrations up to 6·3 log copies/L. Notably, the occurrence of DENV and CHIKV was rather similar between the three regions. The Lisboa and Vale do Tejo region exhibited in general the highest median concentration for DENV and CHIKV following normalization with crAssphage (1·5 × 10 -4 and 1·1 × 10 -3 , respectively). Interpretation We demonstrate the efficacy of wastewater-based surveillance as a potent tool for gauging the epidemiological landscape of both DENV and CHIKV in mainland Portugal, where autochthonous cases have not been detected yet. Therefore, WBS should be integrated as a supplementary component to standard surveillance strategies. Research in context Evidence before this study Wastewater serves as a valuable resource for wastewater-based surveillance (WBS). This surveillance method involves analyzing biomarkers of human metabolism, activities and lifestyle in wastewater to gain insights into public health trends. Previously, WBS has been employed to track chemical substances like illicit drugs, including cocaine, as well as oseltamivir during the 2009 influenza pandemic. It has also played a crucial role in the global polio eradication program by contributing to assess poliovirus circulation in populations and evaluating immunization effectiveness. During the SARS-CoV-2 pandemic, there was a significant boost in wastewater-based surveillance. To the best of our knowledge, our study represents the first extensive application of this approach to comprehensively investigate and identify the presence of vector-borne viruses RNA such as chikungunya and dengue. In December 2022, we conducted a search on PubMed and Google Scholar for publications using the search terms “wastewater” and “dengue virus” or “chikungunya virus” or “West Nile virus” or “Zika virus”, encompassing manuscripts in all languages. Our search yielded only one study that focused on detecting arboviruses in wastewater, specifically Dengue. Surprisingly, the authors were unable to detect viral RNA despite the reported cases of Dengue between 2017 and 2019, when the wastewater samples were collected. This period included a major outbreak in 2019, with more than 7,000 confirmed cases. Remarkably, no other study has shed light on the presence and concentration of Dengue and Chikungunya viral RNA in wastewater. Added value of this study In response to the gap identified in the literature review, this study makes a significant contribution by reporting for the first time the presence and concentration of arboviral RNA, specifically focusing on the Dengue and Chikungunya viruses. Notably, it has demonstrated the circulation of these viruses, even when only a few travel-associated cases have been reported throughout the years and where no autochthonous have been reported within the community, although the vector ( Aedes albopictus ) has been identified in several occasions in mainland Portugal. This research underscores the vital role of wastewater-based surveillance in gaining insights into the circulation trends of underreported pathogens within communities at the sewershed level. Implications of the available information Arboviral infections are significantly underreported, especially in non-endemic countries, and they can lead from mild to severe health issues and even mortality. The symptoms are unspecific and resemble those of various other illnesses, such as Influenza and COVID-19. Consequently, many infected individuals may not seek medical assistance, and when they do, their infections might be misdiagnosed. This results in surveillance for arboviral infections being biased toward individuals presenting with unusual symptoms or severe illness, or returning from endemic regions, leading to delayed reporting and limited temporal and spatial accuracy. In contrast, wastewater surveillance provides results within 24 hours of sample collection and offers a representation of the population served by the sewer system. This includes asymptomatic individuals and those with mild symptoms who may not seek medical care. This approach increases the likelihood of detecting viral circulation and thus prompt public health intervention, namely through vector control, limiting the potential transmission to new hosts, breaking the cycle of transmission. Wastewater surveillance data can play a crucial role in informing public health and environmental decision-making. It can reveal the presence of unaccounted-for infections, indicating the need for control and mitigation strategies, both at the population and mosquito vector levels. Although the arboviral activity is assumed residual in Portugal, wastewater monitoring can be used in complement to the efforts that are already done under the National Vector Surveillance Network. Moreover, this data can be used to communicate with the general public, encouraging them to take actions that can help control the mosquito population, such as reducing stagnant water sources where mosquitoes lay their eggs. This is especially important for vulnerable populations, enabling them to make more informed decisions to mitigate the underlying risks effectively.

ABSTRACT There remains a need to develop novel SARS-CoV-2 therapeutic options that improve upon existing therapies by increased robustness of response, fewer safety liabilities, and global-ready accessibility. Functionally critical viral main protease (M pro , 3CL pro ) of SARS-CoV-2 is an attractive target due to its homology within the coronaviral family, and lack thereof towards human proteases. In this disclosure, we outline the advent of a novel SARS-CoV-2 3CL pro inhibitor, CMX990, bearing an unprecedented trifluoromethoxymethyl ketone warhead. Compared with the marketed drug nirmatrelvir (combination with ritonavir = Paxlovid TM ), CMX990 has distinctly differentiated potency (∼5x more potent in primary cells) and human in vitro clearance (>4x better microsomal clearance and >10x better hepatocyte clearance), with good in vitro - in vivo correlation. Based on its compelling preclinical profile and projected once or twice a day dosing supporting unboosted oral therapy in humans, CMX990 advanced to a Phase 1 clinical trial as an oral drug candidate for SARS-CoV-2.

Although the COVID-19 pandemic appears to be diminishing, the emergence of SARS-CoV-2 variants represents a threat to humans due to its inherent transmissibility, immunological evasion, virulence, and invulnerability to existing therapies. The previous COVID-19 pandemic affected more than 500 million people and caused over 6 million deaths. Vaccines are essential, but in circumstances when vaccination is not accessible or in individuals with compromised immune systems, drugs can give additional protection. Targeting host signaling pathways is recommended due to their genomic stability and resistance barriers. Plant-derived products, which have been used in traditional medicine for treating pathological conditions, offer structurally novel therapeutic compounds including anti-viral. In addition, plant-derived bioactive substances might serve as the ideal basis for developing sustainable/efficient/cost-effective anti-viral alternatives. Epigenetic modifications in the genome can affect gene expression without altering DNA sequence. Host cells can use epigenetic gene regulation as a mechanism to silence incoming viral DNA molecules, while viruses have recruited cellular epi transcriptomic (covalent modifications of RNAs) modifiers to increase the translational efficiency and transcript stability of viral transcripts to enhance viral gene expression and replication. Moreover, viruses manipulate host cells' epigenetic machinery to ensure productive viral infections. Environmental factors, such as natural products, may influence epigenetic modifications. In this review, we are exploring the potential of plant-derived substances as epigenetic modifiers for broad-spectrum anti-viral activity, reviewing modulation processes and anti-viral effects on DNA and RNA viruses, and addressing future research objectives in this rapidly emerging field.

Zika virus (ZIKV) Non-structural protein 1 (NS1) plays an essential role in viral replication and immune evasion. Our understanding of the differential protective mechanism of NS1-targeting antibodies is limited. Here, we determined the cryoEM structures of ZIKV NS1 in complex with two group antibodies at 2.6-2.9Å. Group I antibodies (3G2 and 4B8) potently recognize cell surface form of NS1 and multiple oligomeric forms of NS1 by occupy the epitopes on outer surface of dimeric NS1. IgG and Fab from group I antibodies completely abrogate sNS1-mediated endothelial dysfunction in vitro. Group II antibodies (4F10, 2E11, and 14G5) recognize the previously reported epitopes in distal end of the β -ladder domain of monomeric NS1, and their blockade efficiency depends on the affinity with NS1 protein. These findings elucidate the correlation between the epitope recognition and the protective efficacy of anti-NS1 antibodies and highlight the distinct mechanisms of therapeutic potential of 3G2 and 4B8.

Abstract The Zika virus (ZIKV) is a mosquito-transmitted flavivirus related to the dengue virus that has emerged in recent global outbreaks, with previously unreported neurological or birth abnormalities. There remains a large, unmet need for efficacious vaccines and antiviral agents against ZIKV. Flavivirus non-structural protein 1 (NS1) is the only secreted viral protein that has proven useful in diagnostics. However, its physiologically relevant structural forms and pathogenesis mechanisms remain unclear. While many antibodies targeting NS1 with mapped immunodomain epitopes have been reported, antibody-NS1 structures are starting to emerge, which may guide vaccine and therapeutic design. Here, we present high-resolution cryoEM structures of ZIKV recombinant secreted NS1 (rsNS1) and its complexes with three human monoclonal antibodies, as well as evidence of ZIKV infection-derived secreted NS1 (isNS1) binding to HDL. We showed that ZIKV rsNS1 forms tetramers and filamentous repeats of tetramers. The studied antibodies (AA12, EB9, GB5) did not disrupt the ZIKV NS1 tetramers as they bound to the wing and connector subdomain to the β-ladder. Our study reveals new insights into NS1 multimerization, highlights the need to distinguish the polymorphic nature of rsNS1 and isNS1, and expands the mechanistic basis of the protection conferred by antibodies targeting NS1.

Zika virus (ZikV) infection during pregnancy can cause congenital Zika syndrome (CZS) and neurodevelopmental delay in non-microcephalic infants, of which the pathogenesis remains poorly understood. We utilized an established pigtail macaque maternal-to-fetal ZikV infection/exposure model to study fetal brain pathophysiology of CZS manifesting from ZikV exposure in utero. We found prenatal ZikV exposure led to profound disruption of fetal myelin, with extensive downregulation in gene expression for key components of oligodendrocyte maturation and myelin production. Immunohistochemical analyses revealed marked decreases in myelin basic protein intensity and myelinated fiber density in ZikV-exposed animals. At the ultrastructural level, the myelin sheath in ZikV-exposed animals showed multi-focal decompaction consistent with perturbation or remodeling of previously formed myelin, occurring concomitant with dysregulation of oligodendrocyte gene expression and maturation. These findings define fetal neuropathological profiles of ZikV-linked brain injury underlying CZS resulting from ZikV exposure in utero . Because myelin is critical for cortical development, ZikV-related perturbations in oligodendrocyte function may have long-term consequences on childhood neurodevelopment, even in the absence of overt microcephaly. Graphical abstract