Henipaviruses: an expanding global public health concern?

A conserved motif in Henipavirus P/V/W proteins drives the fibrillation of the W protein from Hendra virus

The Hendra (HeV) and Nipah (NiV) viruses are high-priority, biosafety level-4 pathogens that cause fatal neurological and respiratory disease. Their P gene encodes not only the P protein, an essential polymerase cofactor, but also the virulence factors V and W. We previously showed that the W protein of HeV (WHeV) forms amyloid-like fibrils and that one of its subdomains, PNT3, fibrillates in isolation. However, the fibrillation kinetics is much faster in the case of the full-length WHeV compared to PNT3, suggesting that another WHeV region contributes to the fibrillation process. In this work, we identified the region spanning residues 2-110 (PNT1) as the crucial region implicated in WHeV fibrillation. Through site-directed mutagenesis, combined with thioflavin T binding experiments and negative-staining transmission electron microscopy, we showed that a predicted cryptic amyloidogenic region (CAR) within PNT1 is the main driver of fibrillation and deciphered the underlying molecular mechanism. Using FTIR, we showed that PNT1 fibrils are enriched in cross β-sheets. Sequence alignment revealed conservation of the CAR across the Henipavirus genus and enabled the identification of a hitherto never reported pro-amyloidogenic motif. The ability to form fibrils was experimentally shown to be a common property shared by Henipavirus PNT1 proteins. Overall, this study sheds light on the molecular mechanisms underlying WHeV fibrillation and calls for future studies aimed at exploring the relevance of the newly identified pro-amyloidogenic motif as a valuable target for antiviral approaches.

Genetic Diversity and Geographic Spread of Henipaviruses

Henipaviruses, such as Hendra and Nipah viruses, are major zoonotic pathogens that cause encephalitis and respiratory infections in humans and animals. The recent emergence of Langya virus in China highlights the need to understand henipavirus host diversity and geographic spread to prevent future outbreaks. Our analysis of the National Center for Biotechnology Information Virus and VIRION databases revealed ≈1,117 henipavirus sequences and 142 complete genomes. Bats (64.7%) and shrews (11.7%) dominated the host species record, and the genera Pteropus and Crocidura contained key henipavirus hosts in Asia, Australia, and Africa. Henipaviruses found in the Eidolon bat genus exhibited the highest within-host genetic distance. Phylogenetic analysis revealed batborne and rodent- or shrew-derived henipaviruses diverged ≈11,000 years ago and the first known lineage originating in Eidolon genus bats ≈9,900 years ago. Pathogenic henipaviruses diverged from their ancestors 2,800-1,200 years ago. Including atypical hosts and regions in future investigations is necessary to control future outbreaks.

Human Riboviruses: A Comprehensive Study

The urgency to understand the complex interactions between viruses, their animal reservoirs, and human populations has been necessitated by the continuous spread of zoonotic viral diseases as evidenced in epidemics and pandemics throughout human history. Riboviruses are involved in some of the most prevalent human diseases, responsible for causing epidemics and pandemics. These viruses have an animal origin and have been known to cross the inter-species barrier time and time again, eventually infecting human beings. Their evolution has been a long road to harbour important adaptations for increasing fitness, mutability and virulence; a result of natural selection and mutation pressure, making these viruses highly infectious and difficult to counter. Accumulating favourable mutations in the course, they imitate the GC content and codon usage patterns of the host for maximising the chances of infection. A myriad of viral and host factors determine the fate of specific viral infections, which may include virus protein and host receptor compatibility, host restriction factors and others. Thus, understanding the biology, transmission and molecular mechanisms of Riboviruses is essential for the development of effective antiviral treatments, vaccine development and strategies to prevent and control viral infections. Keeping these aspects in mind, this review aims to provide a holistic approach towards understanding Riboviruses.

Understanding and addressing the global impact: A systematic review and cross-sectional bibliometric analysis of Langya henipavirus and pre-existing severe henipaviruses

In 2022, Langya henipavirus was identified in patients with fever in eastern China. This study provides an overview of the scientific landscape, highlights research focus areas, and outlines potential future investigations. The relevant scientific literature was systematically searched and reviewed via advanced bibliometric techniques. Over the past two decades, henipavirus research has increased at an annual rate of 8.82 %. The United States leads in research output, with the Australian Animal Health Laboratory as the top institution. Most articles are published in the Journal of Virology, identified as the most influential journal along with researcher Wang LF. Current research focuses on "zoonosis," "vaccine," and "pathogenesis," whereas future areas may include "molecular docking," "immunoinformatics," "climate change," "antibodies," "vaccines," "glycoprotein," and "ephrin-b2." This study details henipavirus research, highlighting key players, trends, and future directions. These insights will guide future efforts to address the risks posed by novel Henipaviruses, such as Langya.

Nipah virus: epidemiology, pathogenesis, treatment, and prevention

Nipah virus (NiV) is a zoonotic paramyxovirus that has recently emerged as a crucial public health issue. It can elicit severe encephalitis and respiratory diseases in animals and humans, leading to fatal outcomes, exhibiting a wide range of host species tropism, and directly transmitting from animals to humans or through an intermediate host. Human-to-human transmission associated with recurrent NiV outbreaks is a potential global health threat. Currently, the lack of effective therapeutics or licensed vaccines for NiV necessitates the primary utilization of supportive care. In this review, we summarize current knowledge of the various aspects of the NiV, including therapeutics, vaccines, and its biological characteristics, epidemiology, pathogenesis, and clinical features. The objective is to provide valuable information from scientific and clinical research and facilitate the formulation of strategies for preventing and controlling the NiV.

The RNA Revolution in the Central Molecular Biology Dogma Evolution

Human genome projects in the 1990s identified about 20,000 protein-coding sequences. We are now in the RNA revolution, propelled by the realization that genes determine phenotype beyond the foundational central molecular biology dogma, stating that inherited linear pieces of DNA are transcribed to RNAs and translated into proteins. Crucially, over 95% of the genome, initially considered junk DNA between protein-coding genes, encodes essential, functionally diverse non-protein-coding RNAs, raising the gene count by at least one order of magnitude. Most inherited phenotype-determining changes in DNA are in regulatory areas that control RNA and regulatory sequences. RNAs can directly or indirectly determine phenotypes by regulating protein and RNA function, transferring information within and between organisms, and generating DNA. RNAs also exhibit high structural, functional, and biomolecular interaction plasticity and are modified via editing, methylation, glycosylation, and other mechanisms, which bestow them with diverse intra- and extracellular functions without altering the underlying DNA. RNA is, therefore, currently considered the primary determinant of cellular to populational functional diversity, disease-linked and biomolecular structural variations, and cell function regulation. As demonstrated by RNA-based coronavirus vaccines' success, RNA technology is transforming medicine, agriculture, and industry, as did the advent of recombinant DNA technology in the 1980s.

Zoonotic Paramyxoviruses: Evolution, Ecology, and Public Health Strategies in a Changing World

The family Paramyxoviridae includes a number of negative RNA viruses known for their wide host range and significant zoonotic potential. In recent years, there has been a surge in the identification of emerging zoonotic paramyxoviruses, particularly those hosted by bat species, which serve as key reservoirs. Among these, the genera Henipavirus and Pararubulavirus are of particular concern. Henipaviruses, including the highly pathogenic Hendra and Nipah viruses, have caused severe outbreaks with high mortality rates in both humans and animals. In contrast, zoonotic pararubulaviruses such as the Menangle virus typically induce mild symptoms or remain asymptomatic in human hosts. This review summarizes current knowledge on the evolution, ecology, and epidemiology of emerging zoonotic paramyxoviruses, focusing on recently discovered viruses and their potential to cause future epidemics. We explore the molecular mechanisms underlying host-switching events, viral replication strategies, and immune evasion tactics that facilitate interspecies transmission. In addition, we discuss ecological factors influencing virus emergence, including changes in bat populations and habitats and the role of wildlife-human interfaces. We also examine the public health impact of these emerging viruses, underlining the importance of enhanced surveillance, developing improved diagnostic tools, and implementing proactive strategies to prevent potential outbreaks. By providing a comprehensive overview of recent advances and gaps in knowledge, this review aims to inform future research directions and public health policies related to zoonotic paramyxoviruses.

Structural insights into the Langya virus attachment glycoprotein

Langya virus (LayV) was recently detected in patients with acute pneumonic diseases in China. Genome alignment indicated that LayV is a type of zoonotic henipavirus (HNV) that might also infect domestic animals. Previous studies revealed that HNVs mainly use ephrin-B1, ephrin-B2, or ephrin-B3 as cell receptors and the attachment glycoprotein (G) is the host cell receptor-binding protein. However, the LayV receptor remains unknown. Here, we present the 2.77 Å crystal structure of the LayV G C-terminal domain (CTD). We show that the LayV G protein CTD possesses a similar architecture as the Mojiang virus (MojV) G protein but is markedly different from the Nipah virus (NiV), Hendra virus (HeV), and Cedar virus (CedV) G proteins. Surface plasmon resonance (SPR) experiments indicate that LayV G does not bind ephrin-B proteins. Steric hindrance may prevent interactions between LayV G and ephrin-B. Our data might facilitate drug development targeting LayV.

Recuperative potential of Indian medicinal plant compounds- a tool to encumber henipaviruses: an in -silico study

Henipaviruses, highly fatal zoonotic viruses with mortality rates up to 100%, pose a significant threat to humans. Despite sporadic cases, including infections from Cedar, Langya, and Nipah Viruses, there are no established drugs or vaccines for treatment. This lack of specific medication led us to explore 57 non-toxic compounds from Indian Medicinal Plants, selected from 232 compounds, aiming to combat these viruses. Through in silico ADMET analyses, Three compounds-andrographolide, pterygospermin and Salidroside-stood out for their exceptional non-toxic properties. These compounds underwent in silico target prediction, molecular docking and dynamics with Cedar, Langya, and Nipah Virus proteins from the Protein Data Bank. Among them, Andrographolide displayed the most promising negative free energy scores and stability in Cedar Virus-Attachment G-Protein binding pockets. Pterygospermin and Salidroside showed efficacy against Langya and Nipah Virus target proteins throughout the simulation. These compounds not only exhibited antiviral properties but also demonstrated immunomodulatory, anti-inflammatory, and hepatoprotective effects by our in-silico studies. Their potential as treatments or preventive measures against henipaviral infections makes them promising candidates for further research and development.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00236-x.

Cedar virus biology and its applications as a surrogate for highly pathogenic henipaviruses

Nipah Virus (NiV) and Hendra Virus (HeV), are the prototype species of the genus Henipavirus and are highly pathogenic agents capable of causing fatal diseases in both animals and humans. Both NiV and HeV are classified as biosafety level-4 (BSL-4) restricted pathogens and remain the only henipaviruses within the genus known to cause systemic, severe respiratory and encephalitic henipaviral disease, and represent substantial transboundary threats. There are no approved prophylactic or therapeutic treatments for human henipavirus infections, and the World Health Organization acknowledges them as priority pathogens needing urgent research. The discovery of Cedar virus (CedV), the only recognized non-pathogenic henipavirus, has provided a number of unique opportunities to study henipavirus and host interactions and also facilitate countermeasure development research at lower BSL-2 containment. This review will highlight the unique aspects of CedV biology and how it has been exploited as a model for developing therapeutic strategies against more virulent henipavirus species.

A Comparative Assessment of the Pathogenic Potential of Newly Discovered Henipaviruses

Recent advances in high-throughput sequencing technologies have led to the discovery of a plethora of previously unknown viruses in animal samples. Some of these newly detected viruses are closely related to human pathogens. A prime example are the henipaviruses. Both Nipah (NiV) and Hendra virus (HeV) cause severe disease in humans. Henipaviruses are of zoonotic origin, and animal hosts, including intermediate hosts, play a critical role in viral transmission to humans. The natural reservoir hosts of NiV and HeV seem to be restricted to a few fruit bat species of the Pteropus genus in distinct geographic areas. However, the recent discovery of novel henipa- and henipa-like viruses suggests that these viruses are far more widespread than was originally thought. To date, these new viruses have been found in a wide range of animal hosts, including bats, shrews, and rodents in Asia, Africa, Europe, and South America. Since these viruses are closely related to human pathogens, it is important to learn whether they pose a threat to human health. In this article, we summarize what is known about the newly discovered henipaviruses, highlight differences to NiV and HeV, and discuss their pathogenic potential.

Infection and transmission of henipavirus in animals

Henipavirus (HNV) is well known for two zoonotic viruses in the genus, Hendra virus (HeV) and Nipah virus (NiV), which pose serious threat to human and animal health. In August 2022, a third zoonotic virus in the genus Henipavirus, Langya virus (LayV), was discovered in China. The emergence of HeV, NiV, and LayV highlights the persistent threat of HNV to human and animal health. In addition to the above three HNVs, new species within this genus are still being discovered. Although they have not yet caused a pandemic in humans or livestock, they still have the risk of spillover as a potential threat to the health of humans and animals. It's important to understand the infection and transmission of different HNV in animals for the prevention and control of current or future HNV epidemics. Therefore, this review mainly summarizes the animal origin, animal infection and transmission of HNV that have been found worldwide, and further analyzes and summarizes the rules of infection and transmission, so as to provide a reference for relevant scientific researchers. Furthermore, it can provide a direction for epidemic prevention and control, and animal surveillance to reduce the risk of the global pandemic of HNV.

Square the Circle: Diversity of Viral Pathogens Causing Neuro-Infectious Diseases

Neuroinfections rank among the top ten leading causes of child mortality globally, even in high-income countries. The crucial determinants for successful treatment lie in the timing and swiftness of diagnosis. Although viruses constitute the majority of infectious neuropathologies, diagnosing and treating viral neuroinfections remains challenging. Despite technological advancements, the etiology of the disease remains undetermined in over half of cases. The identification of the pathogen becomes more difficult when the infection is caused by atypical pathogens or multiple pathogens simultaneously. Furthermore, the modern surge in global passenger traffic has led to an increase in cases of infections caused by pathogens not endemic to local areas. This review aims to systematize and summarize information on neuroinvasive viral pathogens, encompassing their geographic distribution and transmission routes. Emphasis is placed on rare pathogens and cases involving atypical pathogens, aiming to offer a comprehensive and structured catalog of viral agents with neurovirulence potential.

Development and evaluation of a quadruple real-time fluorescence-based quantitative reverse transcription polymerase chain reaction assay for detecting Langya, Mojiang, Nipah, and Cedar viruses

The emerging viruses within the genus Henipavirus in the family Paramyxoviridae pose a great threat to public biosafety. To develop a quadruple real-time fluorescence-based quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay is pivotal for the early warning of the potential of zoonotic infectious diseases. Specific primers and probes were designed for the relatively conserved regions based on whole genome sequences of Langya virus (LayV), Mojiang virus (MojV), Nipah virus (NiV), and Cedar virus (CedV), followed by the establishment of a quadruple real-time fluorescence-based qRT-PCR detection method. No cross-reactivity was observed with other viral nucleic acids. The optimal linear detection range for LayV, MojV, NiV, and CedV was 101-108 copies/μL, and the lower limit of detection was 10 copies/μL. Three different DNA concentrations of LayV, MojV, NiV, and CedV (104, 105, and 106 copies/μL) were tested 14 times, achieving good repeatability. The standard deviation of the cycle threshold values for each concentration was <0.5 and the coefficient of variation was <3 %. Furthermore, the amplification efficiency of quadruple real-time fluorescence-based qRT-PCR was >90 %, and the correlation coefficient was >0.99. The established quadruple real-time fluorescence-based qRT-PCR assay for the detection of LayV, MojV, NiV, and CedV exhibits good sensitivity, specificity, and repeatability. Therefore, it can be used to detect Henipavirus and other related clinical specimens.

From fever to action: diagnosis, treatment, and prevention of acute undifferentiated febrile illnesses

Acute Undifferentiated Febrile Illness (AUFI) presents a clinical challenge, often characterized by sudden fever, non-specific symptoms, and potential life-threatening implications. This review highlights the global prevalence, types, challenges, and implications of AUFI, especially in tropical and subtropical regions where infectious diseases thrive. It delves into the difficulties in diagnosis, prevalence rates, regional variations, and potential causes, ranging from bacterial and viral infections to zoonotic diseases. Furthermore, it explores treatment strategies, preventive measures, and the critical role of the One Health approach in addressing AUFI. The paper also addresses the emerging zoonotic risks and ongoing outbreaks, including COVID-19, Rickettsia spp., and other novel pathogens, emphasizing their impact on AUFI diagnosis and management. Challenges in resource-limited settings are analyzed, highlighting the need for bolstered healthcare infrastructure, enhanced diagnostics, and collaborative One Health strategies. Amidst the complexity of emerging zoonotic threats, this review underscores the urgency for a multifaceted approach to mitigate the growing burden of AUFI, ensuring early diagnosis, appropriate treatment, and effective prevention strategies.

Corona- and Paramyxoviruses in Bats from Brazil: A Matter of Concern?

Chiroptera are one of the most diverse mammal orders. They are considered reservoirs of main human pathogens, where coronaviruses (CoVs) and paramyxoviruses (PMVs) may be highlighted. Moreover, the growing number of publications on CoVs and PMVs in wildlife reinforces the scientific community's interest in eco-vigilance, especially because of the emergence of important human pathogens such as the SARS-CoV-2 and Nipha viruses. Considering that Brazil presents continental dimensions, is biologically rich containing one of the most diverse continental biotas and presents a rich biodiversity of animals classified in the order Chiroptera, the mapping of CoV and PMV genetics related to human pathogens is important and the aim of the present work. CoVs can be classified into four genera: Alphacoronavirus, Betacoronavirus, Deltacoronavirus and Gammacoronavirus. Delta- and gammacoronaviruses infect mainly birds, while alpha- and betacoronaviruses contain important animal and human pathogens. Almost 60% of alpha- and betacoronaviruses are related to bats, which are considered natural hosts of these viral genera members. The studies on CoV presence in bats from Brazil have mainly assayed phyllostomid, molossid and vespertilionid bats in the South, Southeast and North territories. Despite Brazil not hosting rhinophilid or pteropodid bats, which are natural reservoirs of SARS-related CoVs and henipaviruses, respectively, CoVs and PMVs reported in Brazilian bats are genetically closely related to some human pathogens. Most works performed with Brazilian bats reported alpha-CoVs that were closely related to other bat-CoVs, despite a few reports of beta-CoVs grouped in the Merbecovirus and Embecovirus subgenera. The family Paramyxoviridae includes four subfamilies (Avulavirinae, Metaparamyxovirinae, Orthoparamyxovirinae and Rubulavirinae), and bats are significant drivers of PMV cross-species viral transmission. Additionally, the studies that have evaluated PMV presence in Brazilian bats have mainly found sequences classified in the Jeilongvirus and Morbillivirus genera that belong to the Orthoparamyxovirinae subfamily. Despite the increasing amount of research on Brazilian bats, studies analyzing these samples are still scarce. When surveying the representativeness of the CoVs and PMVs found and the available genomic sequences, it can be perceived that there may be gaps in the knowledge. The continuous monitoring of viral sequences that are closely related to human pathogens may be helpful in mapping and predicting future hotspots in the emergence of zoonotic agents.

Henipavirus zoonosis: outbreaks, animal hosts and potential new emergence

Hendra virus (HeV) and Nipah virus (NiV) are biosafety level 4 zoonotic pathogens causing severe and often fatal neurological and respiratory disease. These agents have been recognized by the World Health Organization as top priority pathogens expected to result in severe future outbreaks. HeV has caused sporadic infections in horses and a small number of human cases in Australia since 1994. The NiV Malaysia genotype (NiV-M) was responsible for the 1998-1999 epizootic outbreak in pigs with spillover to humans in Malaysia and Singapore. Since 2001, the NiV Bangladesh genotype (NiV-B) has been the predominant strain leading to outbreaks almost every year in Bangladesh and India, with hundreds of infections in humans. The natural reservoir hosts of HeV and NiV are fruit bats, which carry the viruses without clinical manifestation. The transmission pathways of henipaviruses from bats to humans remain poorly understood. Transmissions are often bridged by an intermediate animal host, which amplifies and spreads the viruses to humans. Horses and pigs are known intermediate hosts for the HeV outbreaks in Australia and NiV-M epidemic in Malaysia and Singapore, respectively. During the NiV-B outbreaks in Bangladesh, following initial spillover thought to be through the consumption of date palm sap, the spread of infection was largely human-to-human transmission. Spillover of NiV-B in recent outbreaks in India is less understood, with the primary route of transmission from bat reservoir to the initial human infection case(s) unknown and no intermediate host established. This review aims to provide a concise update on the epidemiology of henipaviruses covering their previous and current outbreaks with emphasis on the known and potential role of livestock as intermediate hosts in disease transmission. Also included is an up-to-date summary of newly emerging henipa-like viruses and animal hosts. In these contexts we discuss knowledge gaps and new challenges in the field and propose potential future directions.

Chimeric vaccine design against the epidemic Langya Henipavirus using immunoinformatics and validation via immune simulation approaches

In July 2022, a new virus called Langya virus (LayV) was discovered in China in patients who had a fever. This virus is a type of Henipavirus (HNV) and is considered a potential threat as it could spread from animals to humans. It causes respiratory disease with symptoms including fever, coughing, and fatigue and is closely linked to two other henipaviruses that are known to infect humans, namely Hendra and Nipah viruses. These viruses may cause fatal respiratory illnesses. Investigators believe that the LayV is spread by shrews, and may have infected humans directly or via an intermediary species. Thus, the use of vaccines or immunizations against LayV is an alternate strategy for disease prevention. In this study, we employed various immunoinformatics methods to predict B cell, HTL and T cell epitopes from the LayV proteome in order to find the most promising candidate for a LayV vaccine. The most potent epitopes that are immunogenic and non-allergenic were joined with each other through suitable linkers. Human β-defensin 2 was employed as an adjuvant to increase the immunogenicity of the vaccine construct. The final sequence of a multi-epitope vaccine construct was modelled for docking with TLRs. Concisely, our results suggest that the docked complexes of vaccine-TLRs seemed to be stable. Additionally, in silico cloning was done using E. coli as the host in order to validate the expression of our designed vaccine construct. The GC content of 54.39% and CAI value of 0.94 revealed that the vaccine component expresses efficiently in the host. This study presents the novel vaccine construct for LayV which will be essential for further experimental validations to confirm the immunogenicity and safety of the proposed vaccine structure, and eventually to treat HNV-related diseases.