Fatal encephalitis due to Nipah virus among pig-farmers in Malaysia

Ephrin B1 and B2 Mediate Cedar Virus Entry into Egyptian Fruit Bat Cells

Cedar virus (CedV), closely related to the Hendra and Nipah viruses, is a novel Henipavirus that was originally isolated from flying foxes in Australia in 2012. Although its glycoprotein G exhibits relatively low sequence similarity with its counterparts of the Hendra and Nipah viruses, CedV also uses ephrin receptors, i.e., ephrins B1, B2, A2 and A5, to enters human cells. Nevertheless, the entry mechanism of CedV into bat cells remains unexplored. Considering that Rousettus aegyptiacus (Egyptian Rousette bat, ERB) is postulated to be a reservoir host for henipaviruses, we aim to reveal the receptors utilized by CedV to enable its entry into ERB cells. To this end, we cloned the class A and B ephrins of ERB and generated CHO-K1 cells stably expressing individual ephrins. We also developed a lentivirus-based pseudovirus system containing the firefly luciferase reporter. Assessment of the luciferase activity in cells expressing single ephrins demonstrated that the ERB ephrin B1 and B2 mediated CedV pseudovirus entry. Further, we generated a recombinant CedV expressing the fluorescent protein TurboFP635 (rCedV-nTurbo635). By performing high-content microscopy and flow cytometry, we unveiled that, in addition to ephrin B1 and B2, ephrin A5 was also able to mediate rCedV-nTurbo635 entry, although to a much lesser extent. In contrast to human ephrin A2, ERB ephrin A2 failed to mediate rCedV-nTurbo635 entry. Finally, we generated ERB epithelial cells with ephrin B1 and/or ephrin B2 knockdown (KD). The entry of rCedV-nTurbo635 into ERB epithelial cells was drastically impaired by ephrin B1/B2 KD, validating the importance of ephrin B1 and B2 in its entry. Altogether, we conclude that CedV primarily employs ERB ephrin B1, B2 and, possibly, A5 for its entry into ERB cells.

Optimal control analysis for the transmission of Nipah infection with imperfect vaccination

This paper presents an innovative mathematical model for assessing the dynamics and optimal control of Nipah virus (NiV) with imperfect vaccination. The model formulation considers transmissions through contaminated food and human-to-human contacts. It also incorporates the potential virus transmission through contact with a deceased body infected with NiV. Initially, the NiV model is assessed theoretically, identifying three distinct equilibrium states: the NiV-endemic equilibrium state, the NiV-free equilibrium state, and the equilibrium state involving infected flying foxes. Furthermore, the stability results of the model in the case of constant controls are thoroughly analyzed at the NiV-free equilibrium. Some of the parameters of the model are estimated based on the infected cases documented in Bangladesh from 2001 to 2017. We further perform sensitivity analysis to determine the most influential parameters and formulate effective time-dependent controls. Numerical simulations indicate the optimal course of action for eradicating the disease and provide a comparative analysis of controlling the infection under constant and time-varying interventions. The simulation confirms that the implementation of time-varying interventions is effective in minimizing disease incidence.

Nipah virus: Preventing the next outbreak

Nipah is a deadly viral infection which has come to the news highlight recently, due to its fresh onslaught in Southern India. As the world continues to recover from coronavirus disease 2019, the World Health Organization has identified a list of high-priority pathogens with the potential to cause future pandemics. Among them is the Nipah virus (NiV), which poses a significant threat. Even a small outbreak could trigger widespread panic among the public. The emergence and re-emergence of NiV among other zoonotic infections is a stern reminder of the importance of One health concept.

Single-dose intranasal AdC68-vectored vaccines rapidly protect Syrian hamsters against lethal Nipah virus infection

Nipah virus (NiV) infection is highly lethal in humans, and the development of vaccines that provide rapid protection is critical for addressing NiV outbreaks. In this study, we demonstrate that a single intranasal immunization with the chimpanzee adenoviral-vectored NiV vaccine, AdC68-F, induced robust and sustained cellular and humoral responses in BALB/c mice, and provided complete protection against challenge with the NiV-Malaysia strain (NiV-M) in Syrian hamsters. Notably, AdC68-F, administered at a dose of 5 × 109 viral particles, offered a complete prophylactic protection window as few as 7 days before exposure to a lethal NiV-M challenge. Furthermore, passive transfer of sera from AdC68-F or AdC68-G immunized animals conferred complete protection against NiV-M infection in naive hamsters. These findings underscore the pivotal role of antigen-specific immunity in controlling NiV infection and highlight the potential of single-dose intranasal AdC68-based NiV vaccines for rapid protection during outbreaks. By providing rapid and effective protection, these vaccines could help reduce human-to-human transmission and aid in curbing NiV outbreaks.

A multifaceted intervention to improve diagnosis and early management of hospitalised patients with suspected acute brain infections in Brazil, India, and Malawi: an international multicentre intervention study

BACKGROUND

Brain infections pose substantial challenges in diagnosis and management and carry high mortality and morbidity, especially in low-income and middle-income countries. We aimed to improve the diagnosis and early management of patients admitted to hospital (adults aged 16 years and older and children aged >28 days) with suspected acute brain infections at 13 hospitals in Brazil, India, and Malawi.

METHODS

With hospital stakeholders, policy makers, and patient and public representatives, we co-designed a multifaceted clinical and laboratory intervention, informed by an evaluation of routine practice. The intervention, tailored for each setting, included a diagnostic and management algorithm, a lumbar puncture pack, a testing panel, and staff training. We used multivariable logistic regression and interrupted time series analysis to compare the coprimary outcomes-the percentage of patients achieving a syndromic diagnosis and the percentage achieving a microbiological diagnosis before and after the intervention. The study was registered at ClinicalTrials.gov (NCT04190303) and is complete.

FINDINGS

Between Jan 5, 2021, and Nov 30, 2022, we screened 10 462 patients and enrolled a total of 2233 patients at 13 hospital sites connected to the four study centres in Brazil, India, and Malawi. 1376 (62%) were recruited before the intervention and 857 (38%) were recruited after the intervention. 2154 patients (96%) had assessment of the primary outcome (1330 [62%] patients recruited pre-intervention and 824 [38%] recruited post-intervention). The median age across centres was 23 years (IQR 6-44), with 1276 (59%) being adults aged 16 years or older and 888 (41%) children aged between 29 days and 15 years; 1264 (59%) patients were male and 890 (41%) were female. Data on race and ethnicity were not recorded. 1020 (77%) of 1320 patients received a syndromic diagnosis before the intervention, rising to 701 (86%) of 813 after the intervention (adjusted odds ratio [aOR] 1·81 [95% CI 1·40-2·34]; p<0·0001). A microbiological diagnosis was made in 294 (22%) of 1330 patients pre-intervention, increasing to 250 (30%) of 824 patients post-intervention (aOR 1·46 [95% CI 1·18-1·79]; p=0·00040). Interrupted time series analysis confirmed that these increases exceeded a modest underlying trend of improvement over time. The percentage receiving a lumbar puncture, time to appropriate therapy, and functional outcome also improved.

INTERPRETATION

Diagnosis and management of patients with suspected acute brain infections improved following introduction of a simple intervention package across a diverse range of hospitals on three continents. The intervention is now being implemented in other settings as part of the WHO Meningitis Roadmap and encephalitis control initiatives.

FUNDING

UK National Institute for Health and Care Research.

Plant-derived Bisphenol C is a drug candidate against Nipah henipavirus infection: an in-vitro and in-silico study of Pouzolzia zeylanica (L.) Benn

Pouzolzia zeylanica (PZ) is a widely distributed medicinal herb throughout Bangladesh, especially in tribal regions. The present study focused on evaluating the bioactivity like antioxidant, cytotoxicity, anti-hemolytic activity through in-vitro assessment and predicted potential antiviral compounds against Nipah virus employing in-silico approaches from stem extract of P. zeylanica. The bioactivities of stem extract showed potent antioxidant and anti-hemolytic activity. Comparatively, its cytotoxicity, with an IC50 of 123.786 ± 1.328 µg/ml, suggests moderate toxicity, making it a potential source for therapeutics. Through GCMS analysis, 17 compounds were identified from the stem extract. On the other hand, the potent ligand targeting attachment glycoprotein, the key factor during the host-pathogen attachment and disease (encephalitis) progression, of the Nipah virus (NiV-G) was predicted through in-silico approaches employing ADMET analysis, molecular docking, quantum mechanics (QM) and molecular dynamic simulation (MDS). With a docking score of - 7.4kCal/mol in molecular docking analysis between phytochemicals and NiV-G, Bisphenol-C (CID6620) has been identified as a potent ligand among the phytochemicals present in PZ stem extract. The QM analysis suggests kinetic stability with better chemical reactivity and the docked complex was found stable in MDS for 100 ns. Based on all those evaluations, the compound could be considered a potent ligand for NiV-G and indicates a promising antiviral drug candidate.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-025-00328-2.

Henipaviruses: epidemiology, ecology, disease, and the development of vaccines and therapeutics

SUMMARYHenipaviruses were first identified 30 years ago and have since been associated with over 30 outbreaks of disease in humans. Highly pathogenic henipaviruses include Hendra virus (HeV) and Nipah virus (NiV), classified as biosafety level 4 pathogens. In addition, NiV has been listed as a priority pathogen by the World Health Organization (WHO), the Coalition for Epidemic Preparedness Innovations (CEPI), and the UK Vaccines Research and Development Network (UKVN). Here, we re-examine epidemiological, ecological, clinical, and pathobiological studies of HeV and NiV to provide a comprehensive guide of the current knowledge and application to identify and evaluate countermeasures. We also discuss therapeutic and vaccine development efforts. Furthermore, with case identification, prevention, and treatment in mind, we highlight limitations in research and recognize gaps necessitating additional studies.

Pathology and host-pathogen interactions in a golden Syrian hamster model of Nipah virus infection

Nipah virus (NiV) is recognized as one of the key pathogens with pandemic potential. We have recently established a NiV hamster model, which reproduces a highly similar disease to that observed in human cases, including respiratory and neurological signs and lesions. The aims of this study were to describe the microscopic lesions observed in the golden Syrian hamster model after intranasal (IN) and intraperitoneal (IP) inoculation with different doses of the Malaysian strain of NiV; to describe in depth the cell composition of the pulmonary and the brain lesions and the expression of proinflammatory cytokines in-situ using a combination of histopathological techniques including immunohistochemistry (IHC) and in-situ hybridisation (ISH) via RNAscope technique. We also developed a multiplex IHC which will allow us to study the interaction of the virus with cell populations in the lung and brain in future studies. For this, we selected 28 lung and brain formalin-fixed paraffin-embedded (FFPE) samples from previous experiments performed by our research group. Histopathology revealed severe pulmonary broncho-interstitial pneumonia, mainly in animals inoculated via the IN route, accompanied by a strong acute inflammatory response (Iba1+ cells) and high levels of NiV RNA. Upregulation of proinflammatory cytokines (IL-6 and TNF) was also observed by ISH RNAscope technique in these animals. Neurological lesions, consisting of perivascular cuffing and meningitis, were observed mainly in animals inoculated via IP route. IHC results showed astrocytosis (GFAP+) and microgliosis (Iba1+) in the brain of these animals, together with mild levels of IL6 and TNF mRNA. These results have helped us to characterize the host-pathogen interaction in the golden Syrian hamster animal model of NiV infection that is being currently used in preclinical testing of antiviral and vaccine strategies. Techniques used in this study could be applied to the development and application of golden Syrian hamster models of other infections by henipaviruses, including Hendra virus (HeV), and other high consequence priority pathogens.

Emerging and re-emerging viral infections of the central nervous system in Australasia and beyond

Viral infections of the central nervous system (CNS) have been emerging and re-emerging worldwide, and the Australasia region has not been spared. Enterovirus A71 and enterovirus D68, both human enteroviruses, are likely to replace the soon-to-be eradicated poliovirus to cause global outbreaks associated with neurological disease. Although prevalent elsewhere, the newly emergent orthoflavivirus, Japanese encephalitis virus (genotype IV), caused human infections in Australia in 2021, and almost certainly will continue to do so because of spillovers from the natural animal host-vector life cycle endemic in the country. Another orthoflavivirus, Murray Valley encephalitis virus, has re-emerged in Australia. The Hendra henipavirus together with Nipah henipavirus ​are listed as high-risk pathogens by the World Health Organization because both can cause lethal encephalitis. The former remains a health threat in Australasia because bats may still be able to spread the infection to unvaccinated Australian horses and other animals acting as intermediate hosts, and thence to humans. The global COVID-19 pandemic, caused by the emerging severe acute respiratory syndrome coronavirus-2, a virus transmitted from animals to humans that was first described and first arose in China, is associated with acute and long-lasting CNS pathology. Fortunately, the pathology and pathogenesis of these important neurotropic viruses are now better understood, leading to better management protocols and prevention strategies. Pathologists are in a unique position to contribute to the diagnosis and advancement in our knowledge of infectious diseases. This review summarises some of the current knowledge about a few important emerging and re-emerging CNS infections in Australasia and beyond.

Nipah Virus-Associated Neuropathology in African Green Monkeys During Acute Disease and Convalescence

BACKGROUND

Nipah virus is an emerging zoonotic virus that causes severe respiratory disease and meningoencephalitis. The pathophysiology of Nipah virus meningoencephalitis is poorly understood.

METHODS

We have collected the brains of African green monkeys during multiple Nipah virus, Bangladesh studies, resulting in 14 brains with Nipah virus-associated lesions.

RESULTS

The lesions seen in the brain of African green monkeys infected with Nipah virus, Bangladesh were very similar to those observed in humans with Nipah virus, Malaysia infection. We observed viral RNA and antigen within neurons and endothelial cells, within encephalitis foci and in uninflamed portions of the central nervous system (CNS). CD8+ T cells had a consistently high prevalence in CNS lesions. We developed a UNet model for quantifying and visualizing inflammation in the brain in a high-throughput and unbiased manner. While CD8+ T cells had a consistently high prevalence in CNS lesions, the model revealed that CD68+ cells were numerically the immune cell with the highest prevalence in the CNS of Nipah virus-infected animals.

CONCLUSIONS

Our study provides an in-depth analysis on Nipah virus infection in the brains of primates, and similarities between lesions in patients and the animals in our study validate this model.

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.

Malaysia outbreak survivors retain detectable Nipah antibodies and memory B cells after 25 years

OBJECTIVE

To evaluate the long-term humoral immune response to Nipah virus (NiV) in a cohort of 25 survivors after 25 years of post-infection.

METHODS

A total of 25 survivors of NiV infection from the 1998 outbreak were recruited for sample collection. The serum IgG antibody response to NiV antigens, specifically nucleocapsid (N), fusion glycoprotein (F) and attachment glycoprotein (G) was evaluated using ELISA. Additionally, the samples were tested for neutralizing antibodies and memory B cell responses.

RESULTS

Detection rates of anti-NiV-F and anti-NiV-G were 56% and 60%, respectively, among the survivors at a 1:100 dilution, whereas only 20% were specifically reactive to rNiV-N. Notably, all samples that tested positive for NiV-F and NiV-G at this dilution also exhibited neutralizing antibodies, highlighting the specificity of these assays. Live virus neutralization assay showed that 72% of survivors had detectable neutralizing antibodies, with varying titers, indicating long-lasting immune memory. Furthermore, memory B cell responses specific to NiV-F and NiV-G were observed in six randomly selected survivors, suggesting the presence of enduring immunological memory.

CONCLUSIONS

These findings highlight the potential of NiV-F and NiV-G as reliable markers for NiV exposure and underscore the need for continuous surveillance and research. Such efforts are crucial for advancing vaccine development and improving preparedness for future NiV outbreaks.

Risk of Nipah Virus Seroprevalence in Healthcare Workers: A Systematic Review with Meta-Analysis

Nipah virus (NiV) is a zoonotic pathogen with the potential to cause human outbreaks with a high case fatality ratio. In this systematic review and meta-analysis, available evidence on NiV infections occurring in healthcare workers (HCWs) was collected and critically appraised. According to the PRISMA statement, four medical databases (PubMed, CINAHL, EMBASE, and Scopus) and the preprint repository medRixv were inquired through a specifically designed searching strategy. A total of 2593 entries were identified; of them, 16 studies were included in qualitative and quantitative analysis detailing the outcome of NiV infection on HCWs and estimates of seroprevalence among healthcare professions. All studies reported data from Asian countries: Malaysia, Singapore, Bangladesh, India (States of Kerala and Bengal), and Philippines. Seroprevalence was estimated from seven studies in 0.00% (95%CI 0.00 to 0.10) for IgM-class antibodies and 0.08% (95%CI 0.00 to 0.72) for IgG class-antibodies, but four of the sampled studies did not report any seropositive cases. A case fatality ratio of 73.52% (95%CI 34.01 to 99.74) was calculated from 10 studies. In conclusion, the present study shows that NiV may result in a possible occupational infection among HCWs involved in managing incident cases. As most NiV outbreaks occur in limited resources settings, it is reasonable that even basic preventive measures (i.e., mandatory use of PPE and appropriate isolation of incident cases with physical distancing) may be quite effective in avoiding the occurrence of new infections among HCWs.

Strengthening Public Health Systems to Combat the Rising Threat of Nipah Virus: A Call for Global Preparedness and Response

The chapter explores ways to increase global preparedness as well as reactions to the Nipah virus, which is a devastating zoonotic risk with serious health impacts. The Nipah virus is transmitted through bats and humans and poses major problems due to its high mortality rate, fast spread, and the absence of treatments or vaccines. The chapter argues for a holistic strategy incorporating the One Health framework to address human, animal, and environmental health interdependence. The chapter focuses on key areas to boost readiness, which include creating effective real-time surveillance systems, enhancing medical infrastructure, and accelerating studies on therapeutics and vaccines. The chapter emphasizes the need for efficient risk communication and engagement with the community to control the spread of disease. In addition, the chapter examines the importance of maintaining international health security financing as well as international collaboration to improve the ability to respond and prepare. Through analyzing case studies that have proven successful and policy recommendations, the chapter seeks to offer an outline for the development of robust health systems that are resilient and reduce the effects of the Nipah virus as well as other newly discovered pathogens.

Nipah virus outbreak trends in Bangladesh during the period 2001 to 2024: a brief review

Nipah virus (NiV) is a zoonotic threat that has caused recurrent outbreaks in Bangladesh since 2001, raising significant public health concerns. This study provides a descriptive analysis of NiV outbreaks from 2001 to 2024, examining trends in infection and death rates and their correlation with climatic factors such as temperature, humidity, and rainfall. The findings highlight significant spikes in NiV cases during specific years, with environmental factors, particularly temperature and precipitation, showing solid correlations with outbreak patterns. The study also explores the impact of population dynamics on transmission risks, including urbanization and density. By focusing on these factors, this research supports the development of targeted public health interventions in high-risk areas, particularly in Bangladesh's northwestern and central districts, where recurrent outbreaks have been observed. These insights improve surveillance and preventive strategies for mitigating future NiV outbreaks.

Nipah virus survey in Pteropus medius of eastern and northeastern region of India, 2022-2023

Introduction

India has experienced seven outbreaks of the Nipah virus (NiV) since 2001, primarily occurring in the southern and eastern regions of the country. The southern region has been the main site for these outbreaks. In contrast, the eastern region, which borders Bangladesh, has not reported any outbreaks since 2007. However, Bangladesh continues to experience nearly annual outbreaks, indicating a significant lack of surveillance in that area. To improve the country's preparedness and to gather support for enhancing public health surveillance in eastern and northeastern states near the area affected by the NiV, a cross-sectional survey was conducted to determine the prevalence of NiV in the bat species Pteropus medius in Bihar, West Bengal, Assam, and Meghalaya states in India, which are adjacent to Bangladesh.

Methods

Throat and rectal swabs, blood samples, and organ samples were collected. Real-time quantitative reverse transcription PCR (qRT-PCR) was utilized for the detection of Nipah viral RNA, and sequencing was conducted for further confirmation. Bat IgG enzyme-linked immunosorbent assay (ELISA) was employed for antibody detection.

Results

Throat and rectal swab samples of 212 P. medius tested for NiV using qRT- PCR were found negative, whereas organ samples of two (one each from West Bengal and Bihar) out of the 10 bats collected tested positive. The retrieved NiV genome (~91%) showed close homology to the NiV-Bangladesh genotype indicating the circulation of two geographically distinct NiV strains in India. The seroprevalence estimated by ELISA ranged from 23 to 65% in the studied states.

Discussion

The serological and virological evidence obtained from the study indicates that a broader geographical area is under threat of spillover in India. It's crucial to implement a One Health approach connecting bat surveillance studies with human surveillance and risk factor studies in the region.

Pandemic potential of the Nipah virus and public health strategies adopted during outbreaks: Lessons from Kerala, India

Kerala, a south Indian state witnessed several outbreaks of Nipah encephalitis since 2018, a zoonotic viral disease with significant pandemic potential. This review highlights the relevance of surveillance and health system preparedness, infection control, early diagnosis and treatment with broad-spectrum antivirals, environmental conservation, and community engagement in mitigating Nipah outbreaks. Additionally, it emphasises the importance of developing new biologicals and anti-viral drugs to combat the disease. The article discusses the available evidence on the spillover mechanisms, genetic attributes of the circulating virus, ecological factors, risk of hospital-based superspreading, treatment outcomes and successful strategies employed in Kerala in response to the recurrent Nipah outbreaks.

Establishing an immune correlate of protection for Nipah virus in nonhuman primates

The limited but recurrent outbreaks of the zoonotic Nipah virus (NiV) infection in humans, its high fatality rate, and the potential virus transmission from human to human make NiV a concerning threat with pandemic potential. There are no licensed vaccines to prevent infection and disease. A recombinant Hendra virus soluble G glycoprotein vaccine (HeV-sG-V) candidate was recently tested in a Phase I clinical trial. Because NiV outbreaks are sporadic, and with a few cases, licensing will likely require an alternate regulatory licensing pathway. Therefore, determining a reliable vaccine correlate of protection (CoP) will be critical. We assessed the immune responses elicited by HeV-sG-V in African Green monkeys and its relationship with protection from a NiV challenge. Data revealed values of specific binding and neutralizing antibody titers that predicted survival and allowed us to establish a mechanistic CoP for NiV Bangladesh and Malaysia strains.

Cryo-EM structure of Nipah virus RNA polymerase complex

Nipah virus, a member of the Paramyxoviridae family, is a highly pathogenic nonsegmented, negative-sense RNA virus (nsNSV) which causes severe neurological and respiratory illnesses in humans. There are no available drugs or vaccines to combat this virus. A complex of large polymerase protein (L) and phosphoprotein (P) of Nipah virus supports replication and transcription and affords a target for antiviral drug development. Structural information required for drug development is lacking. Here we report the 2.9-angstrom cryo-electron microscopy structure of the Nipah virus polymerase-phosphoprotein complex. The structure identifies conserved amino acids likely important for recognition of template RNA by nsNSVs and reveals the locations of mutation-prone sites among Nipah virus strains, which may facilitate the development of therapeutic agents against Nipah virus by targeting regions unaffected by these mutation sites.

Gastrointestinal Shedding of Rubulaviruses from Egyptian Rousette Bats: Temporal Dynamics and Spillover Implications

Bats are recognized as reservoirs for diverse paramyxoviruses, some of which are closely related to known human pathogens or directly implicated in zoonotic transmission. The emergence of the zoonotic Sosuga virus (SOSV) from Egyptian rousette bats (ERBs), which caused an acute febrile illness in a reported human case in Africa, has increased the focus on the zoonotic potential of the Rubulavirinae subfamily. Previous studies identified human parainfluenza virus 2 (HPIV2)- and mumps (MuV)-related viruses in ERBs from South Africa, with HPIV2-related viruses restricted to gastrointestinal samples, an underexplored target for rubulavirus biosurveillance, suggesting that sample-type bias may have led to their oversight. To address this, we performed a longitudinal analysis of population-level fecal samples from an ERB maternity roost for rubulavirus RNA, employing a broadly reactive hemi-nested RT-PCR assay targeting the polymerase gene. We detected HPIV2- and MuV-related viruses in addition to numerous pararubulaviruses, highlighting significant viral diversity. Temporal analysis of three major clades revealed peaks in rubulavirus shedding that correlated with seasonal environmental changes and host reproductive cycles, although shedding patterns varied between clades. These findings identify specific periods of increased risk for the spillover of bat-associated rubulaviruses to humans, providing critical information for developing targeted mitigation strategies to minimize zoonotic transmission risk within the local community.

Streamlined detection of Nipah virus antibodies using a split NanoLuc biosensor

Nipah virus (NiV) is an emerging zoonotic RNA virus that can cause fatal respiratory and neurological diseases in animals and humans. Accurate NiV diagnostics and surveillance tools are crucial for the identification of acute and resolved infections and to improve our understanding of NiV transmission and circulation. Here, we have developed and validated a split NanoLuc luciferase NiV glycoprotein (G) biosensor for detecting antibodies in clinical and animal samples. This assay is performed by simply mixing reagents and measuring luminescence, which depends on the complementation of the split NanoLuc luciferase G biosensor following its binding to antibodies. This anti-NiV-G "mix-and-read" assay was validated using the WHO's first international standard for anti-NiV antibodies and more than 700 serum samples from the NiV-endemic country of Bangladesh. Anti-NiV antibodies from survivors persisted for at least 8 years according to both ⍺NiV-G mix-and-read and NiV neutralization assays. The ⍺NiV-G mix-and-read assay sensitivity (98.6%) and specificity (100%) were comparable to anti-NiV IgG ELISA performance but failed to detect anti-NiV antibodies in samples collected less than a week following the appearance of symptoms. Overall, the anti-NiV-G biosensor represents a simple, fast, and reliable tool that could support the expansion of NiV surveillance and retrospective outbreak investigations.

Risk Evaluation and Mitigation Strategies for Potential Outbreaks of Nipah Virus Infection: Evidenced by the Recent Incidences in Southeast Asian Countries

Background

The importance of studying Nipah virus (NiV) stems from its high fatality rates and potential for causing widespread outbreaks. Recent incidences in Southeast Asian countries highlight the urgent need for effective risk evaluation and mitigation strategies.

Justification

Studying NiV in Southeast Asia is crucial due to the geographic and epidemiological significance that makes this region predominantly susceptible to the virus.

Objectives

This study aims to identify the risk factors of NiV, evaluate current mitigation strategies, and suggest improvements against this virus.

Methods

This review incorporates articles from the PubMed database related to available NiV treatments, vaccines, mitigation strategies, transmission data, and mortality to comprise an extensive analysis of pertinent information.

Findings

NiV warrants international attention, due to the high mortality rate and the rising number of human-to-human transmission vectors. NiV is difficult to diagnose early on in the infection due to its generic symptoms, and the two strains of NiV (B and M), pose significant challenges to healthcare institutions. Vaccines, such as the VSV-stored, virus-like particle-based, and mRNA-based NiV show promising results in both animal and human studies. Synthetic medicines, like Ribavirin, and favipiravir showed promising results in NiV-infected patients. Therapeutic infectious particles increased survival from 10% to roughly 70%-80% in animals. Phytochemicals, like serpentine and neoandrographolide are alternatives to NiV-G ligands. Griffithsin, an algae derivative has also shown efficacy in treating NiV infections. Artificial intelligence determines the NiV infection with an accuracy of 88.3%.

Conclusions

The strategies to control NiV must be one of a One Health approach, incorporating environmental and social factors. Extensive research on vaccines that showed promising results in animals needs to be tested for humans on a large scale. The major mitigation strategy available is the public awareness during the outbreak about NiV transmission vectors, quarantine protocol, and food hygiene.

Ferritin nanoparticle-based Nipah virus glycoprotein vaccines elicit potent protective immune responses in mice and hamsters

Nipah virus (NiV) is a zoonotic paramyxovirus in the genus Henipavirus that is prevalent in Southeast Asia. NiV leads to severe respiratory disease and encephalitis in humans and animals, with a mortality rate of up to 75%. Despite the grave threat to public health and global biosecurity, no medical countermeasures are available for humans. Here, based on self-assembled ferritin nanoparticles (FeNPs), we successfully constructed two candidate FeNP vaccines by loading mammalian cells expressing NiV sG (residues 71-602, FeNP-sG) and Ghead (residues 182-602, FeNP-Ghead) onto E. coli-expressed FeNPs (FeNP-sG and FeNP-Ghead, respectively) through Spycatcher/Spytag technology. Compared with sG and Ghead alone, FeNP-sG and FeNP-Ghead elicited significant NiV specific neutralizing antibody levels and T-cell responses in mice, whereas the immune response in the FeNP-sG immunized group was greater than that in the FeNP-Ghead group. These results further demonstrate that sG possesses greater antigenicity than Ghead and that FeNPs can dramatically enhance immunogenicity. Furthermore, FeNP-sG provided 100% protection against NiV challenge in a hamster model when it was administered twice at a dose of 5 μg/per animal. Our study provides not only a promising candidate vaccine against NiV, but also a theoretical foundation for the design of a NiV immunogen for the development of novel strategies against NiV infection.

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.

Therapeutics for Nipah virus disease: a systematic review to support prioritisation of drug candidates for clinical trials

Nipah virus disease is a bat-borne zoonosis with person-to-person transmission, a case-fatality rate of 38-75%, and well recognised potential to cause a pandemic. The first reported outbreak of Nipah virus disease occurred in Malaysia and Singapore in 1998, which has since been followed by multiple outbreaks in Bangladesh and India. To date, no therapeutics or vaccines have been approved to treat Nipah virus disease, and only few such candidates are in development. In this Review, we aim to assess the safety and efficacy of the therapeutic options (monoclonal antibodies and small molecules) for Nipah virus disease and other henipaviral diseases to support prioritisation of drug candidates for further evaluation in clinical trials. At present, sufficient evidence exists to suggest trialling 1F5, m102.4, and remdesivir (alone or in combination) for prophylaxis and early treatment of Nipah virus disease. In addition to well designed clinical efficacy trials, in-vivo pharmacokinetic-pharmacodynamic studies are needed to optimise the selection and dosing of therapeutic candidates in animal challenge and natural human infection.

Measures to prevent and treat Nipah virus disease: research priorities for 2024-29

Nipah virus causes highly lethal disease, with case-fatality rates ranging from 40% to 100% in recognised outbreaks. No treatments or licensed vaccines are currently available for the prevention and control of Nipah virus infection. In 2019, WHO published an advanced draft of a research and development roadmap for accelerating development of medical countermeasures, including diagnostics, therapeutics, and vaccines, to enable effective and timely emergency response to Nipah virus outbreaks. This Personal View provides an update to the WHO roadmap by defining current research priorities for development of Nipah virus medical countermeasures, based primarily on literature published in the last 5 years and consensus opinion of 15 subject matter experts with broad experience in development of medical countermeasures for Nipah virus or experience in the epidemiology, ecology, or public health control of outbreaks of Nipah virus. The research priorities are organised into four main sections: cross-cutting issues (for those that apply to more than one category of medical countermeasures), diagnostics, therapeutics, and vaccines. The strategic goals and milestones identified in each section focus on key achievements that are needed over the next 6 years to ensure that the necessary tools are available for rapid response to future outbreaks of Nipah virus or related henipaviruses.

A systematic review of case reports on mortality, modes of infection, diagnostic tests, and treatments for Nipah virus infection

BACKGROUND

First identified in Malaysia in 1998, the Nipah virus is a paramyxovirus related to the Hendra virus. The clinical manifestation can vary from a silent infection to a life-threatening encephalitis. The World Health Organization (WHO) has documented 25 outbreaks in South Asia, resulting in 429 cases and 307 deaths to date. Currently, there are no approved treatments for the deadly Nipah virus infection, which is a serious threat to public health worldwide. Consequently, a review was conducted to examine the geographic distribution of the Nipah virus, mortality, transmission pathways, and available methods for diagnosis and treatment.

METHODS

PubMed, Scopus, Web of Science, and Google Scholar servers were used to conduct a systematic search in compliance with the PRISMA guidelines. The results were tabulated and analyzed.

RESULTS

A total of 12 studies (7 case series and 5 case reports) were included in the final analysis, and 92 cases were analyzed. The most frequent symptoms were fever (80%), myalgia (47%), headache (47%), shortness of breath/acute respiratory distress syndrome (n = 44.1%), altered sensorium (44.1%), and vomiting (42.6%). The most commonly used diagnostic test was RT-PCR (45.5%). The most common route of transmission reported is direct human contact with the infected patients. Treatment modalities include interventional procedures, antiviral drugs, and symptomatic treatment. The most common complications were seizures (39.2%) and altered sensorium (35.7%). The mortality rate was 73.9%.

CONCLUSION

It is crucial to emphasize the importance of early Nipah virus infection diagnosis and treatment to prevent life-threatening consequences.

Organotypic brain slices as a model to study the neurotropism of the highly pathogenic Nipah and Ebola viruses

Nipah virus (NiV) and Ebola virus (EBOV) are highly pathogenic zoonotic viruses with case fatality rates of up to 90%. While the brain is a known target organ following NiV infection, involvement of the central nervous system in EBOV-infected patients only became more evident after the West African epidemic in 2013-2016. To gain a deeper comprehension of the neurotropism of NiV and EBOV with respect to target cells, affected brain regions and local inflammatory responses, murine organotypic brain slices (BS) were established and infected. Both NiV and EBOV demonstrated the capacity to infect BS from adult wt mice and mice lacking the receptor for type I IFNs (IFNAR-/-) and targeted various cell types. NiV was observed to replicate in BS derived from both mouse strains, yet no release of infectious particles was detected. In contrast, EBOV replication was limited in both BS models. The release of several pro-inflammatory cytokines and chemokines, including eotaxin, IFN-γ, IL-1α, IL-9, IL-17a and keratinocyte-derived chemokine (KC), was observed in both virus-infected models, suggesting a potential role of the inflammatory response in NiV- or EBOV-induced neuropathology. It is noteworthy that the choroid plexus was identified as a highly susceptible target for EBOV and NiV infection, suggesting that the blood-cerebrospinal fluid barrier may serve as a potential entry point for these viruses.

Molecular determinants of cross-species transmission in emerging viral infections

SUMMARYSeveral examples of high-impact cross-species transmission of newly emerging or re-emerging bat-borne viruses, such as Sudan virus, Nipah virus, and severe acute respiratory syndrome coronavirus 2, have occurred in the past decades. Recent advancements in next-generation sequencing have strengthened ongoing efforts to catalog the global virome, in particular from the multitude of different bat species. However, functional characterization of these novel viruses and virus sequences is typically limited with regard to assessment of their cross-species potential. Our understanding of the intricate interplay between virus and host underlying successful cross-species transmission has focused on the basic mechanisms of entry and replication, as well as the importance of host innate immune responses. In this review, we discuss the various roles of the respective molecular mechanisms underlying cross-species transmission using different recent bat-borne viruses as examples. To delineate the crucial cellular and molecular steps underlying cross-species transmission, we propose a framework of overall characterization to improve our capacity to characterize viruses as benign, of interest, or of concern.

The emergence, isolation, and phylogenetic analysis of a closely related human strain of parainfluenza virus 5 from a case of porcine reproductive and respiratory syndrome in China

Reports of Parainfluenza virus 5 (PIV5) epidemics have been on a global upward trend, with an expanding host range across various animals. In 2020, we isolated a PIV5 strain from a PRRSV-positive serum sample. This strain was named GX2020. Genetic analysis revealed that GX2020 belongs to group A, represented by the AGS strain isolated from a human in the USA. Comparisons of amino acid identity in the coding regions showed that GX2020 had the highest amino acid identity (99.6%) with the AGS strain. The emergence of PIV5 strains genetically similar to human strains in pigs highlights its zoonotic potential and underscores the need for enhanced PIV5 surveillance in the future.

Rousettus aegyptiacus Fruit Bats Do Not Support Productive Replication of Cedar Virus upon Experimental Challenge

Cedar henipavirus (CedV), which was isolated from the urine of pteropodid bats in Australia, belongs to the genus Henipavirus in the family of Paramyxoviridae. It is closely related to the Hendra virus (HeV) and Nipah virus (NiV), which have been classified at the highest biosafety level (BSL4) due to their high pathogenicity for humans. Meanwhile, CedV is apathogenic for humans and animals. As such, it is often used as a model virus for the highly pathogenic henipaviruses HeV and NiV. In this study, we challenged eight Rousettus aegyptiacus fruit bats of different age groups with CedV in order to assess their age-dependent susceptibility to a CedV infection. Upon intranasal inoculation, none of the animals developed clinical signs, and only trace amounts of viral RNA were detectable at 2 days post-inoculation in the upper respiratory tract and the kidney as well as in oral and anal swab samples. Continuous monitoring of the body temperature and locomotion activity of four animals, however, indicated minor alterations in the challenged animals, which would have remained unnoticed otherwise.

Development of Fusion-Based Assay as a Drug Screening Platform for Nipah Virus Utilizing Baculovirus Expression Vector System

Nipah virus (NiV) is known to be a highly pathogenic zoonotic virus, which is included in the World Health Organization Research & Development Blueprint list of priority diseases with up to 70% mortality rate. Due to its high pathogenicity and outbreak potency, a therapeutic countermeasure against NiV is urgently needed. As NiV needs to be handled within a Biological Safety Level (BSL) 4 facility, we had developed a safe drug screening platform utilizing a baculovirus expression vector system (BEVS) based on a NiV-induced syncytium formation that could be handled within a BSL-1 facility. To reconstruct the NiV-induced syncytium formation in BEVS, two baculoviruses were generated to express recombinant proteins that are responsible for inducing the syncytium formation, including one baculovirus exhibiting co-expressed NiV fusion protein (NiV-F) and NiV attachment glycoprotein (NiV-G) and another exhibiting human EphrinB2 protein. Interestingly, syncytium formation was observed in infected insect cells when the medium was modified to have a lower pH level and supplemented with cholesterol. Fusion inhibitory properties of several compounds, such as phytochemicals and a polysulfonated naphthylamine compound, were evaluated using this platform. Among these compounds, suramin showed the highest fusion inhibitory activity against NiV-induced syncytium in the baculovirus expression system. Moreover, our in silico results provide a molecular-level glimpse of suramin's interaction with NiV-G's central hole and EphrinB2's G-H loop, which could be the possible reason for its fusion inhibitory activity.

A systematic review on Nipah virus: global molecular epidemiology and medical countermeasures development

Nipah virus (NiV) is an emerging pathogen that causes encephalitis and a high mortality rate in infected subjects. This systematic review aimed to comprehensively analyze the global epidemiology and research advancements of NiV to identify the key knowledge gaps in the literature. Articles searched using literature databases, namely PubMed, Scopus, Web of Science, and Science Direct yielded 5,596 articles. After article screening, 97 articles were included in this systematic review, comprising 41 epidemiological studies and 56 research developments on NiV. The majority of the NiV epidemiological studies were conducted in Bangladesh, reflecting the country's significant burden of NiV outbreaks. The initial NiV outbreak was identified in Malaysia in 1998, with subsequent outbreaks reported in Bangladesh, India, and the Philippines. Transmission routes vary by country, primarily through pigs in Malaysia, consumption of date palm juice in Bangladesh, and human-to-human in India. However, the availability of NiV genome sequences remains limited, particularly from Malaysia and India. Mortality rates also vary according to the country, exceeding 70% in Bangladesh, India, and the Philippines, and less than 40% in Malaysia. Understanding these differences in mortality rate among countries is crucial for informing NiV epidemiology and enhancing outbreak prevention and management strategies. In terms of research developments, the majority of studies focused on vaccine development, followed by phylogenetic analysis and antiviral research. While many vaccines and antivirals have demonstrated complete protection in animal models, only two vaccines have progressed to clinical trials. Phylogenetic analyses have revealed distinct clades between NiV Malaysia, NiV Bangladesh, and NiV India, with proposals to classify NiV India as a separate strain from NiV Bangladesh. Taken together, comprehensive OneHealth approaches integrating disease surveillance and research are imperative for future NiV studies. Expanding the dataset of NiV genome sequences, particularly from Malaysia, Bangladesh, and India will be pivotal. These research efforts are essential for advancing our understanding of NiV pathogenicity and for developing robust diagnostic assays, vaccines and therapeutics necessary for effective preparedness and response to future NiV outbreaks.

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.

Low-Input, High-Resolution 5' Terminal Filovirus RNA Sequencing with ViBE-Seq

Although next-generation sequencing (NGS) has been instrumental in determining the genomic sequences of emerging RNA viruses, de novo sequence determination often lacks sufficient coverage of the 5' and 3' ends of the viral genomes. Since the genome ends of RNA viruses contain the transcription and genome replication promoters that are essential for viral propagation, a lack of terminal sequence information hinders the efforts to study the replication and transcription mechanisms of emerging and re-emerging viruses. To circumvent this, we have developed a novel method termed ViBE-Seq (Viral Bona Fide End Sequencing) for the high-resolution sequencing of filoviral genome ends using a simple yet robust protocol with high fidelity. This technique allows for sequence determination of the 5' end of viral RNA genomes and mRNAs with as little as 50 ng of total RNA. Using the Ebola virus and Marburg virus as prototypes for highly pathogenic, re-emerging viruses, we show that ViBE-Seq is a reliable technique for rapid and accurate 5' end sequencing of filovirus RNA sourced from virions, infected cells, and tissue obtained from infected animals. We also show that ViBE-Seq can be used to determine whether distinct reverse transcriptases have terminal deoxynucleotidyl transferase activity. Overall, ViBE-Seq will facilitate the access to complete sequences of emerging viruses.

Mapping the distribution of Nipah virus infections: a geospatial modelling analysis

BACKGROUND

Nipah virus is a zoonotic paramyxovirus responsible for disease outbreaks with high fatality rates in south and southeast Asia. However, knowledge of the potential geographical extent and risk patterns of the virus is poor. We aimed to establish an integrated spatiotemporal and phylogenetic database of Nipah virus infections in humans and animals across south and southeast Asia.

METHODS

In this geospatial modelling analysis, we developed an integrated database containing information on the distribution of Nipah virus infections in humans and animals from 1998 to 2021. We conducted phylodynamic analysis to examine the evolution and migration pathways of the virus and meta-analyses to estimate the adjusted case-fatality rate. We used two boosted regression tree models to identify the potential ecological drivers of Nipah virus occurrences in spillover events and endemic areas, and mapped potential risk areas for Nipah virus endemicity.

FINDINGS

749 people and eight bat species across nine countries were documented as being infected with Nipah virus. On the basis of 66 complete genomes of the virus, we identified two clades-the Bangladesh clade and the Malaysia clade-with the time of the most recent common ancestor estimated to be 1863. Adjusted case-fatality rates varied widely between countries and were higher for the Bangladesh clade than for the Malaysia clade. Multivariable meta-regression analysis revealed significant relationships between case-fatality rate estimates and viral clade (p=0·0021), source country (p=0·016), proportion of male patients (p=0·036), and travel time to health-care facilities (p=0·036). Temperature-related bioclimate variables and the probability of occurrence of Pteropus medius were important contributors to both the spillover and the endemic infection models.

INTERPRETATION

The suitable niches for Nipah virus are more extensive than previously reported. Future surveillance efforts should focus on high-risk areas informed by updated projections. Specifically, intensifying zoonotic surveillance efforts, enhancing laboratory testing capacity, and implementing public health education in projected high-risk areas where no human cases have been reported to date will be crucial. Additionally, strengthening wildlife surveillance and investigating potential modes of transmission in regions with documented human cases is needed.

FUNDING

The Key Research and Development Program of China.

A highly effective ferritin-based divalent nanoparticle vaccine shields Syrian hamsters against lethal Nipah virus

The Nipah virus (NiV), a highly deadly bat-borne paramyxovirus, poses a substantial threat due to recurrent outbreaks in specific regions, causing severe respiratory and neurological diseases with high morbidity. Two distinct strains, NiV-Malaysia (NiV-M) and NiV-Bangladesh (NiV-B), contribute to outbreaks in different geographical areas. Currently, there are no commercially licensed vaccines or drugs available for prevention or treatment. In response to this urgent need for protection against NiV and related henipaviruses infections, we developed a novel homotypic virus-like nanoparticle (VLP) vaccine co-displaying NiV attachment glycoproteins (G) from both strains, utilizing the self-assembling properties of ferritin protein. In comparison to the NiV G subunit vaccine, our nanoparticle vaccine elicited significantly higher levels of neutralizing antibodies and provided complete protection against a lethal challenge with NiV infection in Syrian hamsters. Remarkably, the nanoparticle vaccine stimulated the production of antibodies that exhibited superior cross-reactivity to homologous or heterologous henipavirus. These findings underscore the potential utility of ferritin-based nanoparticle vaccines in providing both broad-spectrum and long-term protection against NiV and emerging zoonotic henipaviruses challenges.

A Luciferase Immunosorbent Assay Based on Attachment Glycoprotein for the Rapid and Easy Detection of Nipah Virus IgG Antibodies

Nipah virus (NiV) is a virulent zoonotic disease whose natural host is the fruit bat (Pteropus medius), which can coexist with and transmit the virus. Due to its high pathogenicity, wide host range, and pandemic potential, establishing a sensitive, specific, and rapid diagnostic method for NiV is key to preventing and controlling its spread and any outbreaks. Here, we established a luciferase immunosorbent assay (LISA) based on the NiV attachment glycoprotein (G) to detect NiV-specific immunoglobulin G by expressing a fusion protein of nanoluciferase (NanoLuc) and the target antigen. Sensitivity analysis was performed and compared to an indirect enzyme-linked immunosorbent assay (ELISA), and specificity and cross-reactivity assessments were performed using NiV-positive horse serum and Ebola virus-, Crimean-Congo hemorrhagic fever virus-, and West Nile virus-positive horse sera. The optimal structural domain for NiV detection was located within amino acids 176-602 of the NiV G protein head domain. Moreover, the LISA showed at least fourfold more sensitivity than the indirect ELISA, and the cross-reactivity results suggested that the LISA had good specificity and was capable of detecting NiV-specific immunoglobulin G in both mouse and horse serum. In conclusion, the establishment of a rapid, simple NiV LISA using the G protein head domain provides a resource for NiV monitoring.

Potent human neutralizing antibodies against Nipah virus derived from two ancestral antibody heavy chains

Nipah virus (NiV) is a World Health Organization priority pathogen and there are currently no approved drugs for clinical immunotherapy. Through the use of a naïve human phage-displayed Fab library, two neutralizing antibodies (NiV41 and NiV42) targeting the NiV receptor binding protein (RBP) were identified. Following affinity maturation, antibodies derived from NiV41 display cross-reactivity against both NiV and Hendra virus (HeV), whereas the antibody based on NiV42 is only specific to NiV. Results of immunogenetic analysis reveal a correlation between the maturation of antibodies and their antiviral activity. In vivo testing of NiV41 and its mature form (41-6) show protective efficacy against a lethal NiV challenge in hamsters. Furthermore, a 2.88 Å Cryo-EM structure of the tetrameric RBP and antibody complex demonstrates that 41-6 blocks the receptor binding interface. These findings can be beneficial for the development of antiviral drugs and the design of vaccines with broad spectrum against henipaviruses.

Surveillance of Nipah virus in Pteropus medius of Kerala state, India, 2023

Introduction

Since 2018, the Indian state of Kerala has reported four Nipah virus (NiV) disease outbreaks, raising concerns about NiV spillover from bats to the human population. Considering this, a cross-sectional study was undertaken in the Pteropus medius bat population around the Nipah virus-affected regions of Kozhikode, Kerala, India, during February, July, and September 2023.

Methods

Throat swabs, rectal swabs, and organ samples were collected from bats to test for NiV using the real-time reverse transcriptase polymerase chain reaction (RT-PCR), while serum samples were screened for anti-Nipah IgG antibodies through ELISA.

Results

An overall seroprevalence of 20.9% was observed in 272 P. medius bats tested. The throat and rectal swab samples of 321 bats were negative for NiV RNA. However, 4 of 44 P. medius bats tested positive for NiV in their liver/spleen samples. The partial N gene retrieved showed more than 99% similarity with the earlier reported NiV genome from Kerala state, India.

Discussion

The findings of the study caution that there is a spillover risk in the region and necessary precautions should be taken.

Clinico-epidemiological presentations and management of Nipah virus infection during the outbreak in Kozhikode district, Kerala state, India 2023

India experienced its sixth Nipah virus (NiV) outbreak in September 2023 in the Kozhikode district of Kerala state. The NiV is primarily transmitted by spillover events from infected bats followed by human-to-human transmission. The clinical specimens were screened using real-time RT-PCR, and positive specimens were further characterized using next-generation sequencing. We describe here an in-depth clinical presentation and management of NiV-confirmed cases and outbreak containment activities. The current outbreak reported a total of six cases with two deaths, with a case fatality ratio of 33.33%. The cases had a mixed presentation of acute respiratory distress syndrome and encephalitis syndrome. Fever was a persistent presentation in all the cases. The Nipah viral RNA was detected in clinical specimens until the post-onset day of illness (POD) 14, with viral load in the range of 1.7-3.3 × 104 viral RNA copies/mL. The genomic analysis showed that the sequences from the current outbreak clustered into the Indian clade similar to the 2018 and 2019 outbreaks. This study highlights the vigilance of the health system to detect and effectively manage the clustering of cases with clinical presentations similar to NiV, which led to early detection and containment activities.

Prefusion stabilization of the Hendra and Langya virus F proteins

Nipah virus (NiV) and Hendra virus (HeV) are pathogenic paramyxoviruses that cause mild-to-severe disease in humans. As members of the Henipavirus genus, NiV and HeV use an attachment (G) glycoprotein and a class I fusion (F) glycoprotein to invade host cells. The F protein rearranges from a metastable prefusion form to an extended postfusion form to facilitate host cell entry. Prefusion NiV F elicits higher neutralizing antibody titers than postfusion NiV F, indicating that stabilization of prefusion F may aid vaccine development. A combination of amino acid substitutions (L104C/I114C, L172F, and S191P) is known to stabilize NiV F in its prefusion conformation, although the extent to which substitutions transfer to other henipavirus F proteins is not known. Here, we perform biophysical and structural studies to investigate the mechanism of prefusion stabilization in F proteins from three henipaviruses: NiV, HeV, and Langya virus (LayV). Three known stabilizing substitutions from NiV F transfer to HeV F and exert similar structural and functional effects. One engineered disulfide bond, located near the fusion peptide, is sufficient to stabilize the prefusion conformations of both HeV F and LayV F. Although LayV F shares low overall sequence identity with NiV F and HeV F, the region around the fusion peptide exhibits high sequence conservation across all henipaviruses. Our findings indicate that substitutions targeting this site of conformational change might be applicable to prefusion stabilization of other henipavirus F proteins and support the use of NiV as a prototypical pathogen for henipavirus vaccine antigen design.IMPORTANCEPathogenic henipaviruses such as Nipah virus (NiV) and Hendra virus (HeV) cause respiratory symptoms, with severe cases resulting in encephalitis, seizures, and coma. The work described here shows that the NiV and HeV fusion (F) proteins share common structural features with the F protein from an emerging henipavirus, Langya virus (LayV). Sequence alignment alone was sufficient to predict which known prefusion-stabilizing amino acid substitutions from NiV F would stabilize the prefusion conformations of HeV F and LayV F. This work also reveals an unexpected oligomeric interface shared by prefusion HeV F and NiV F. Together, these advances lay a foundation for future antigen design targeting henipavirus F proteins. In this way, Nipah virus can serve as a prototypical pathogen for the development of protective vaccines and monoclonal antibodies to prepare for potential henipavirus outbreaks.

In search of a pan-coronavirus vaccine: next-generation vaccine design and immune mechanisms

Members of the coronaviridae family are endemic to human populations and have caused several epidemics and pandemics in recent history. In this review, we will discuss the feasibility of and progress toward the ultimate goal of creating a pan-coronavirus vaccine that can protect against infection and disease by all members of the coronavirus family. We will detail the unmet clinical need associated with the continued transmission of SARS-CoV-2, MERS-CoV and the four seasonal coronaviruses (HCoV-OC43, NL63, HKU1 and 229E) in humans and the potential for future zoonotic coronaviruses. We will highlight how first-generation SARS-CoV-2 vaccines and natural history studies have greatly increased our understanding of effective antiviral immunity to coronaviruses and have informed next-generation vaccine design. We will then consider the ideal properties of a pan-coronavirus vaccine and propose a blueprint for the type of immunity that may offer cross-protection. Finally, we will describe a subset of the diverse technologies and novel approaches being pursued with the goal of developing broadly or universally protective vaccines for coronaviruses.

Prevalence Estimation and Genetic Characterization of Porcine Parainfluenza Virus 1 (PPIV-1) in Hungary and the First Report of the Virus in Slovakia

In the last few decades, many new paramyxoviruses have been discovered, causing diverse, mostly respiratory diseases in animals and humans. The porcine parainfluenza virus 1 (PPIV-1, species Porcine respirovirus 1), which has been reported in many countries worldwide, was found in both healthy and clinically ill pigs showing respiratory signs. Here, we report the expected prevalence and genetic diversity of PPIV-1 in Hungarian pig herds and the detection in one Slovakian pig farm, which is the first report of evidence for the presence of the virus in the country. To estimate the prevalence in Hungary 211 oral fluid samples were collected from 23 large-scale swine herds in a systematic way and tested by real-time quantitative RT-PCR. The presence of the virus was detected in 10 of the 23 Hungarian farms (43%) included in our study. One hundred eighty-one nasal swab samples were collected cross-sectionally from three Hungarian and one Slovakian PPIV-1-positive herd and PPIV-1 was most prevalent in 6-week-old pigs on farms located in Hungary and in the 2-week-old pigs on the Slovakian farm. Phylogenetic analysis of three Hungarian and two Slovakian PPIV-1 F-gene sequences showed high-nucleotide identity (>93%) and all belonged to Clade I, together with the other European strains.

Emerging and re-emerging pediatric viral diseases: a continuing global challenge

The twenty-first century has been marked by a surge in viral epidemics and pandemics, highlighting the global health challenge posed by emerging and re-emerging pediatric viral diseases. This review article explores the complex dynamics contributing to this challenge, including climate change, globalization, socio-economic interconnectedness, geopolitical tensions, vaccine hesitancy, misinformation, and disparities in access to healthcare resources. Understanding the interactions between the environment, socioeconomics, and health is crucial for effectively addressing current and future outbreaks. This scoping review focuses on emerging and re-emerging viral infectious diseases, with an emphasis on pediatric vulnerability. It highlights the urgent need for prevention, preparedness, and response efforts, particularly in resource-limited communities disproportionately affected by climate change and spillover events. Adopting a One Health/Planetary Health approach, which integrates human, animal, and ecosystem health, can enhance equity and resilience in global communities. IMPACT: We provide a scoping review of emerging and re-emerging viral threats to global pediatric populations This review provides an update on current pediatric viral threats in the context of the COVID-19 pandemic This review aims to sensitize clinicians, epidemiologists, public health practitioners, and policy stakeholders/decision-makers to the role these viral diseases have in persistent pediatric morbidity and mortality.

Recently Emerged Novel Henipa-like Viruses: Shining a Spotlight on the Shrew

Henipaviruses are zoonotic viruses, including some highly pathogenic and capable of serious disease and high fatality rates in both animals and humans. Hendra virus and Nipah virus are the most notable henipaviruses, resulting in significant outbreaks across South Asia, South-East Asia, and Australia. Pteropid fruit bats have been identified as key zoonotic reservoirs; however, the increased discovery of henipaviruses outside the geographic distribution of Pteropid fruit bats and the detection of novel henipa-like viruses in other species such as the shrew, rat, and opossum suggest that Pteropid bats are not the sole reservoir for henipaviruses. In this review, we provide an update on henipavirus spillover events and describe the recent detection of novel unclassified henipaviruses, with a strong focus on the shrew and its emerging role as a key host of henipaviruses.

Genomic characterization, transcriptome analysis, and pathogenicity of the Nipah virus (Indian isolate)

Nipah virus (NiV) is a high-risk pathogen which can cause fatal infections in humans. The Indian isolate from the 2018 outbreak in the Kerala state of India showed ~ 4% nucleotide and amino acid difference in comparison to the Bangladesh strains of NiV and the substitutions observed were mostly not present in the region of any functional significance except for the phosphoprotein gene. The differential expression of viral genes was observed following infection in Vero (ATCC® CCL-81™) and BHK-21 cells. Intraperitoneal infection in the 10-12-week-old, Syrian hamster model induced dose dependant multisystemic disease characterized by prominent vascular lesions in lungs, brain, kidney and extra vascular lesions in brain and lungs. Congestion, haemorrhages, inflammatory cell infiltration, thrombosis and rarely endothelial syncitial cell formation were seen in the blood vessels. Intranasal infection resulted in respiratory tract infection characterised by pneumonia. The model showed disease characteristics resembling the human NiV infection except that of myocarditis similar to that reported by NiV-Malaysia and NiV-Bangladesh isolates in hamster model. The variation observed in the genome of the Indian isolate at the amino acid levels should be explored further for any functional significance.

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Pathogenicity and virulence of henipaviruses

Paramyxoviruses are a family of single-stranded negative-sense RNA viruses, many of which are responsible for a range of respiratory and neurological diseases in humans and animals. Among the most notable are the henipaviruses, which include the deadly Nipah (NiV) and Hendra (HeV) viruses, the causative agents of outbreaks of severe disease and high case fatality rates in humans and animals. NiV and HeV are maintained in fruit bat reservoirs primarily in the family Pteropus and spillover into humans directly or by an intermediate amplifying host such as swine or horses. Recently, non-chiropteran associated Langya (LayV), Gamak (GAKV), and Mojiang (MojV) viruses have been discovered with confirmed or suspected ability to cause disease in humans or animals. These viruses are less genetically related to HeV and NiV yet share many features with their better-known counterparts. Recent advances in surveillance of wild animal reservoir viruses have revealed a high number of henipaviral genome sequences distributed across most continents, and mammalian orders previously unknown to harbour henipaviruses. In this review, we summarize the current knowledge on the range of pathogenesis observed for the henipaviruses as well as their replication cycle, epidemiology, genomics, and host responses. We focus on the most pathogenic viruses, including NiV, HeV, LayV, and GAKV, as well as the experimentally non-pathogenic CedV. We also highlight the emerging threats posed by these and potentially other closely related viruses.