Isolation of Nipah virus from Malaysian Island flying-foxes

Egyptian rousette bats maintain long-term protective immunity against Marburg virus infection despite diminished antibody levels

Although bats are natural reservoir hosts for numerous zoonotic viruses, little is known about the long-term dynamics of the host immune response following infection and how these viruses are maintained in nature. The Egyptian rousette bat (ERB) is a known reservoir host for Marburg virus (MARV). Following infection of ERBs with MARV, virus-specific IgG antibodies are induced but rapidly wane and by 3 months post-infection the bats are seronegative. To determine whether reinfection of ERBs plays a role in MARV maintenance, we challenge groups of ERBs that were “naturally” or experimentally infected with MARV 17–24 months prior. No bats in either group exhibit evidence of MARV replication or shedding and all bats develop virus-specific secondary immune responses. This study demonstrates that infection of ERBs with MARV induces long-term protective immunity against reinfection and indicates that other factors, such as host population dynamics, drive MARV maintenance in nature.

A VLP-based vaccine provides complete protection against Nipah virus challenge following multiple-dose or single-dose vaccination schedules in a hamster model

Nipah virus is a highly lethal zoonotic paramyxovirus that was first recognized in Malaysia during an outbreak in 1998. During this outbreak, Nipah virus infection caused a severe febrile neurological disease in humans who worked in close contact with infected pigs. The case fatality rate in humans was approximately 40%. Since 2001, NiV has re-emerged in Bangladesh and India where fruit bats (Pteropus spp.) have been identified as the principal reservoir of the virus. Transmission to humans is considered to be bat-to-human via food contaminated with bat saliva, or consumption of contaminated raw date palm sap, although human-to-human transmission of Nipah virus has also been documented. To date, there are no approved prophylactic options or treatment for NiV infection. In this study, we produced mammalian cell-derived native Nipah virus-like particles composed of Nipah virus G, F and M proteins for use as a novel Nipah virus vaccine. Previous studies demonstrated that the virus-like particles were structurally similar to authentic virus, functionally assembled and immunoreactive. In the studies reported here, purified Nipah virus-like particles were utilized either alone or with adjuvant to vaccinate golden Syrian hamsters with either three-dose or one-dose vaccination regimens followed by virus challenge. These studies found that Nipah virus-like particle immunization of hamsters induced significant neutralizing antibody titers and provided complete protection to all vaccinated animals following either single or three-dose vaccine schedules. These studies prove the feasibility of a virus-like particle-based vaccine for protection against Nipah virus infection.

Potential risk of viral transmission from flying foxes to domestic animals and humans on the southern coast of West Java, Indonesia

Flying foxes have been considered to be involved in the transmission of serious infectious diseases to humans. Using questionnaires, we aimed to determine the direct and/or indirect contacts of flying foxes in an Indonesian nature conservation area with domestic animals and humans living in the surrounding area. We surveyed 150 residents of 10 villages in West Java. Villages were classified into 3 groups: inside and/or within 1 km from the outer border of the conservation area and 1–5 km or 5–10 km away from the reserve’s outer border. Data were collected by direct interview using a structured questionnaire consisting of the respondent characteristics (age, sex and occupation); histories of contacts between flying foxes and humans, dogs and other domestic animals; and knowledge about infectious diseases, mainly rabies, in flying foxes. We found that flying foxes from the nature conservation area often enter residential areas at night to look for food, especially during the fruit season. In these residential areas, flying foxes had direct contacts with humans and a few contacts with domestic animals, especially dogs. People who encounter flying foxes seldom used personal protective equipment, such as leather gloves, goggles and caps. The residents living around the conservation area mostly had poor knowledge about flying foxes and disease transmission. This situation shows that the population in this region is at a quite high risk for contracting infectious diseases from flying foxes.

A Review of Zoonotic Infection Risks Associated with the Wild Meat Trade in Malaysia

The overhunting of wildlife for food and commercial gain presents a major threat to biodiversity in tropical forests and poses health risks to humans from contact with wild animals. Using a recent survey of wildlife offered at wild meat markets in Malaysia as a basis, we review the literature to determine the potential zoonotic infection risks from hunting, butchering and consuming the species offered. We also determine which taxa potentially host the highest number of pathogens and discuss the significant disease risks from traded wildlife, considering how cultural practices influence zoonotic transmission. We identify 51 zoonotic pathogens (16 viruses, 19 bacteria and 16 parasites) potentially hosted by wildlife and describe the human health risks. The Suidae and the Cervidae families potentially host the highest number of pathogens. We conclude that there are substantial gaps in our knowledge of zoonotic pathogens and recommend performing microbial food safety risk assessments to assess the hazards of wild meat consumption. Overall, there may be considerable zoonotic risks to people involved in the hunting, butchering or consumption of wild meat in Southeast Asia, and these should be considered in public health strategies.

Bat Astroviruses: Towards Understanding the Transmission Dynamics of a Neglected Virus Family

Bats belong to the order Chiroptera that represents the second largest order of mammals with more than 1200 species and an almost global distribution. Environmental changes and deforestation have severely influenced many ecosystems, intensifying the contact between wildlife and humans. In recent years, bats have been found to harbor a number of different viruses with zoonotic potential, as well as a great diversity of astroviruses, for which the question of zoonotic potential remains unanswered to date. Human astroviruses have been identified as the causative agent for diarrhea in children and immunocompromised patients. For a long time, astroviruses have been considered to be strictly species-specific. However, a great genetic diversity has recently been discovered among animal and human astroviruses that might indicate the potential of these viruses to cross species barriers. Furthermore, our knowledge about the tissue tropism of astroviruses has been expanded to some neurotropic strains that have recently been shown to be responsible for encephalitis in humans and livestock. This review gives an overview on what is known about astroviruses in bats, humans and livestock, especially bovines and pigs. Future research activities are suggested to unravel astrovirus infection dynamics in bat populations to further assess the zoonotic potential of these viruses.

Understanding the interaction between henipaviruses and their natural host, fruit bats: Paving the way toward control of highly lethal infection in humans

Hendra virus and Nipah virus (NiV) are highly pathogenic zoonotic paramyxoviruses, from henipavirus genus, that have emerged in late 1990s in Australia and South-East Asia, respectively. Since their initial identification, numerous outbreaks have been reported, affecting both domestic animals and humans, and multiple rounds of person-to-person NiV transmission were observed. Widely distributed fruit bats from Pteropodidae family were found to be henipavirus natural reservoir. Numerous studies have reported henipavirus seropositivity in pteropid bats, including bats in Africa, thus expanding notably the geographic distribution of these viruses. Interestingly, henipavirus infection in bats seems to be asymptomatic, in contrast to severe disease induced in numerous other mammals. Unique among the mammals by their ability to fly, these intriguing animals are natural reservoir for many other emerging and remerging viruses highly pathogenic for humans. This feature, combined with absence of clinical symptoms, has attracted the interest of scientific community to virus-bat interactions. Therefore, several bat genomes were sequenced and particularities of the bat immune system have been intensively analyzed during the last decade to understand their coexistence with viruses in the absence of disease. The peculiarities in inflammasome activation, a constitutive expression of interferon alpha, and some differences in adaptive immunity have been recently reported in fruit bats. Studies on virus-bat interactions have thus emerged as an exciting novel area of research that should shed new light on the mechanisms that regulate viral infection and may allow development of novel therapeutic approaches to control this highly lethal emerging infectious disease in humans.

Henipaviruses: bat-borne paramyxoviruses

Found on every continent except Antarctica, bats are one of the most abundant, diverse and geographically widespread vertebrates globally, making up approximately 20% of all known extant mammal species1,2. Noted for being the only mammal with the ability of powered flight, bats constitute the order Chiroptera (from the Ancient Greek meaning ‘hand wing’), which is further divided into two suborders: Megachiroptera known as megabats or flying foxes, and Microchiroptera comprising of echolocating microbats1,3.

Unlocking bat immunology: establishment of Pteropus alecto bone marrow-derived dendritic cells and macrophages

Bats carry and shed many emerging infectious disease agents including Ebola virus and SARS-like Coronaviruses, yet they rarely display clinical symptoms of infection. Bat epithelial or fibroblast cell lines were previously established to study the bat immune response against viral infection. However, the lack of professional immune cells such as dendritic cells (DC) and macrophages has greatly limited the significance of current investigations. Using Pteropus alecto (P. alecto) GM-CSF plus IL4, FLT3L and CSF-1, we successfully generated bat bone marrow-derived DC and macrophages. Cells with the phenotype, morphology and functional features of monocyte-derived DC, bona fide DC or macrophages were obtained in GM-CSF/IL4, FLT3L or CSF-1 cultures, respectively. The successful generation of the first bat bone marrow-derived immune cells paves the way to unlocking the immune mechanisms that confer host resilience to pathogens in bats.

A Generic Quantitative Risk Assessment Framework for the Entry of Bat-Borne Zoonotic Viruses into the European Union

Bat-borne viruses have been linked to a number of zoonotic diseases; in 2014 there have been human cases of Nipah virus (NiV) in Bangladesh and Ebola virus in West and Central Africa. Here we describe a model designed to provide initial quantitative predictions of the risk of entry of such viruses to European Union (EU) Member States (MSs) through four routes: human travel, legal trade (e.g. fruit and animal products), live animal movements and illegal importation of bushmeat. The model utilises available datasets to assess the movement via these routes between individual countries of the world and EU MSs. These data are combined with virus specific data to assess the relative risk of entry between EU MSs. As a case study, the model was parameterised for NiV. Scenario analyses showed that the selection of exporting countries with NiV and potentially contaminated trade products were essential to the accuracy of all model outputs. Uncertainty analyses of other model parameters identified that the model expected number of years to an introduction event within the EU was highly susceptible to the prevalence of NiV in bats. The relative rankings of the MSs and routes, however, were more robust. The UK, the Netherlands and Germany were consistently the most likely points of entry and the ranking of most MSs varied by no more than three places (maximum variation five places). Legal trade was consistently the most likely route of entry, only falling below human travel when the estimate of the prevalence of NiV in bats was particularly low. Any model-based calculation is dependent on the data available to feed into the model and there are distinct gaps in our knowledge, particularly in regard to various pathogen/virus as well as host/bat characteristics. However, the strengths of this model lie in the provision of relative comparisons of risk among routes and MSs. The potential for expansion of the model to include other routes and viruses and the possibility of rapid parameterisation demonstrates its potential for use in an outbreak situation.

Development and Evaluation of Recombinant Nucleocapsid Protein Based Diagnostic ELISA for Detection of Nipah Virus Infection in Pigs

The recombinant viral protein-based indirect enzyme-linked immunosorbent assay (ELISA) is a cost-effective, safe, specific, and rapid tool to diagnose the viral infection. Nipah virus nucleocapsid (NiV-N) protein was expressed in Escherichia coli and purified by histidine tag-based affinity chromatography. The N protein was selected based on its immuno dominance and conservation among different NiV strains. An indirect immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) for swine sera was optimized using the recombinant NiV-N protein as an antigen along with negative and positive controls. The background reading was blocked using skim milk powder and chicken serum. A total number of 1709 swine serum samples from various states of India were tested with indirect ELISA and Western blot. The test was considered positive only when its total reactivity reading was higher than 0.2 cut-off value and the ratio of the total reactivity to the background reading was more than 2.0. Since specificity is high for Western blotting it was used as standard test for comparison of results of indirect ELISA. Sensitivity and specificity of indirect ELISA was 100% and 98.7%, respectively, in comparison with Western blotting. Recombinant N protein-based ELISA can be used in screening large number of serum samples for epidemiological investigations in developing countries where high containment laboratories are not available to handle this zoonotic virus.

Eco-social processes influencing infectious disease emergence and spread

The complexity and connectedness of eco-social processes have major influence on the emergence and spread of infectious diseases amongst humans and animals. The disciplinary nature of most research activity has made it difficult to improve our understanding of interactions and feedback loops within the relevant systems. Influenced by the One Health approach, increasing efforts have recently been made to address this knowledge gap. Disease emergence and spread is strongly influenced by host density and contact structures, pathogen characteristics and pathogen population and molecular evolutionary dynamics in different host species, and host response to infection. All these mechanisms are strongly influenced by eco-social processes, such as globalization and urbanization, which lead to changes in global ecosystem dynamics, including patterns of mobility, human population density and contact structures, and food production and consumption. An improved understanding of epidemiological and eco-social processes, including their interdependence, will be essential to be able to manage diseases in these circumstances. The interfaces between wild animals, domestic animals and humans need to be examined to identify the main risk pathways and put in place appropriate mitigation. Some recent examples of emerging infectious disease are described to illustrate eco-social processes that are influencing disease emergence and spread.

Isolation of Tioman virus from Pteropus giganteus bat in North-East region of India

Bat-borne viral diseases are a major public health concern among newly emerging infectious diseases which includes severe acute respiratory syndrome, Nipah, Marburg and Ebola virus disease. During the survey for Nipah virus among bats at North-East region of India; Tioman virus (TioV), a new member of the Paramyxoviridae family was isolated from tissues of Pteropus giganteus bats for the first time in India. This isolate was identified and confirmed by RT-PCR, sequence analysis and electron microscopy. A range of vertebrate cell lines were shown to be susceptible to Tioman virus. Negative electron microscopy study revealed the "herringbone" morphology of the nucleocapsid filaments and enveloped particles with distinct envelope projections a characteristic of the Paramyxoviridae family. Sequence analysis of Nucleocapsid gene of TioV demonstrated sequence identity of 99.87% and 99.99% nucleotide and amino acid respectively with of TioV strain isolated in Malaysia, 2001. This report demonstrates the first isolation of Tioman virus from a region where Nipah virus activity has been noticed in the past and recent years. Bat-borne viruses have become serious concern world-wide. A Survey of bats for novel viruses in this region would help in recognizing emerging viruses and combating diseases caused by them.

Bats as Viral Reservoirs

Bats are hosts of a range of viruses, including ebolaviruses, and many important human viral infections, such as measles and mumps, may have their ancestry traced back to bats. Here, I review viruses of all viral families detected in global bat populations. The viral diversity in bats is substantial, and viruses with all known types of genomic structures and replication strategies have been discovered in bats. However, the discovery of viruses is not geographically even, with some apparently undersampled regions, such as South America. Furthermore, some bat families, including those with global or wide distributions such as Emballonuridae and Miniopteridae, are underrepresented on viral databases. Future studies, including those that address these sampling gaps along with those that develop our understanding of viral-host relationships, are highlighted.

It's not only what you say, it's also how you say it: communicating nipah virus prevention messages during an outbreak in Bangladesh

BACKGROUND

During a fatal Nipah virus (NiV) outbreak in Bangladesh, residents rejected biomedical explanations of NiV transmission and treatment and lost trust in the public healthcare system. Field anthropologists developed and communicated a prevention strategy to bridge the gap between the biomedical and local explanation of the outbreak.

METHODS

We explored residents' beliefs and perceptions about the illness and care-seeking practices and explained prevention messages following an interactive strategy with the aid of photos showed the types of contact that can lead to NiV transmission from bats to humans by drinking raw date palm sap and from person-to-person.

RESULTS

The residents initially believed that the outbreak was caused by supernatural forces and continued drinking raw date palm sap despite messages from local health authorities to stop. Participants in community meetings stated that the initial messages did not explain that bats were the source of this virus. After our intervention, participants responded that they now understood how NiV could be transmitted and would abstain from raw sap consumption and maintain safer behaviours while caring for patients.

CONCLUSIONS

During outbreaks, one-way behaviour change communication without meaningful causal explanations is unlikely to be effective. Based on the cultural context, interactive communication strategies in lay language with supporting evidence can make biomedical prevention messages credible in affected communities, even among those who initially invoke supernatural causal explanations.

Pathogenic Differences between Nipah Virus Bangladesh and Malaysia Strains in Primates: Implications for Antibody Therapy

Nipah virus (NiV) is a paramyxovirus that causes severe disease in humans and animals. There are two distinct strains of NiV, Malaysia (NiV_M) and Bangladesh (NiV_B). Differences in transmission patterns and mortality rates suggest that NiV_B may be more pathogenic than NiV_M. To investigate pathogenic differences between strains, 4 African green monkeys (AGM) were exposed to NiV_M and 4 AGMs were exposed to NiV_B. While NiV_B was uniformly lethal, only 50% of NiV_M-infected animals succumbed to infection. Histopathology of lungs and spleens from NiV_B-infected AGMs was significantly more severe than NiV_M-infected animals. Importantly, a second study utilizing 11 AGMs showed that the therapeutic window for human monoclonal antibody m102.4, previously shown to rescue AGMs from NiV_M infection, was much shorter in NiV_B-infected AGMs. Together, these data show that NiV_B is more pathogenic in AGMs under identical experimental conditions and suggests that postexposure treatments may need to be NiV strain specific for optimal efficacy.

Genomic characterization of a novel poxvirus from a flying fox: evidence for a new genus?

The carcass of an Australian little red flying fox (Pteropus scapulatus) which died following entrapment on a fence was submitted to the laboratory for Australian bat lyssavirus exclusion testing, which was negative. During post-mortem, multiple nodules were noted on the wing membranes, and therefore degenerate PCR primers targeting the poxvirus DNA polymerase gene were used to screen for poxviruses. The poxvirus PCR screen was positive and sequencing of the PCR product demonstrated very low, but significant, similarity with the DNA polymerase gene from members of the Poxviridae family. Next-generation sequencing of DNA extracted from the lesions returned a contig of 132 353 nucleotides (nt), which was further extended to produce a near full-length viral genome of 133 492 nt. Analysis of the genome revealed it to be AT-rich with inverted terminal repeats of at least 1314 nt and to contain 143 predicted genes. The genome contains a surprisingly large number (29) of genes not found in other poxviruses, one of which appears to be a homologue of the mammalian TNF-related apoptosis-inducing ligand (TRAIL) gene. Phylogenetic analysis indicates that the poxvirus described here is not closely related to any other poxvirus isolated from bats or other species, and that it likely should be placed in a new genus.

Molecular epidemiology and phylogeny of Nipah virus infection: A mini review

Nipah virus (NiV) is a member of the genus Henipavirus of the family Paramyxoviridae, characterized by high pathogenicity and endemic in South Asia. It is classified as a Biosafety Level-4 (BSL-4) agent. The case-fatality varies from 40% to 70% depending on the severity of the disease and on the availability of adequate healthcare facilities. At present no antiviral drugs are available for NiV disease and the treatment is just supportive. Phylogenetic and evolutionary analyses can be used to help in understanding the epidemiology and the temporal origin of this virus. This review provides an overview of evolutionary studies performed on Nipah viruses circulating in different countries. Thirty phylogenetic studies have been published from 2000 to 2015 years, searching on pub-med using the key words 'Nipah virus AND phylogeny' and twenty-eight molecular epidemiological studies from 2006 to 2015 have been performed, typing the key words 'Nipah virus AND molecular epidemiology'. Overall data from the published study demonstrated as phylogenetic and evolutionary analysis represent promising tools to evidence NiV epidemics, to study their origin and evolution and finally to act with effective preventive measure.

Detection of viruses using discarded plants from wild mountain gorillas and golden monkeys

Infectious diseases pose one of the most significant threats to the survival of great apes in the wild. The critically endangered mountain gorilla (Gorilla beringei beringei) is at high risk for contracting human pathogens because approximately 60% of the population is habituated to humans to support a thriving ecotourism program. Disease surveillance for human and non-human primate pathogens is important for population health and management of protected primate species. Here, we evaluate discarded plants from mountain gorillas and sympatric golden monkeys (Cercopithecus mitis kandti), as a novel biological sample to detect viruses that are shed orally. Discarded plant samples were tested for the presence of mammalian-specific genetic material and two ubiquitous DNA and RNA primate viruses, herpesviruses, and simian foamy virus. We collected discarded plant samples from 383 wild human-habituated mountain gorillas and from 18 habituated golden monkeys. Mammalian-specific genetic material was recovered from all plant species and portions of plant bitten or chewed by gorillas and golden monkeys. Gorilla herpesviral DNA was most consistently recovered from plants in which leafy portions were eaten by gorillas. Simian foamy virus nucleic acid was recovered from plants discarded by golden monkeys, indicating that it is also possible to detect RNA viruses from bitten or chewed plants. Our findings show that discarded plants are a useful non-invasive sampling method for detection of viruses that are shed orally in mountain gorillas, sympatric golden monkeys, and potentially other species. This method of collecting specimens from discarded plants is a new non-invasive sampling protocol that can be combined with collection of feces and urine to evaluate the most common routes of viral shedding in wild primates. Am. J. Primatol. 78:1222-1234, 2016. © 2016 Wiley Periodicals, Inc.

Isolation and identification of bat viruses closely related to human, porcine and mink orthoreoviruses

Bats have been identified as natural reservoirs of many viruses, including reoviruses. Recent studies have demonstrated the interspecies transmission of bat reoviruses to humans. In this study, we report the isolation and molecular characterization of six strains of mammalian orthoreovirus (MRV) from Hipposideros and Myotis spp. These isolates were grouped into MRV serotype 1, 2 or 3 based on the sequences of the S1 gene, which encodes the outer coat protein s1. Importantly, we found that three of six bat MRV strains shared high similarity with MRVs isolated from diseased minks, piglets or humans based on the S1 segment, suggesting that interspecies transmission has occurred between bats and humans or animals. Phylogenetic analyses based on the 10 segments showed that the genomic segments of these bat MRVs had different evolution lineages, suggesting that these bat MRVs may have arisen through reassortment of MRVs of different origins.

Serum from Nipah Virus Patients Recognises Recombinant Viral Proteins Produced in Escherichia coli

The genes for Nipah virus (NiV) proteins were amplified from viral RNA, cloned into the plasmid pTriEx-3 Hygro, expressed, and purified using immobilized metal affinity chromatography. The recombinant N, F, and G NiV proteins (rNiV-N, rNiV-F, and rNiV-G), were successfully expressed in Escherichia coli and purified with a yield of 4, 16, and 4 mg/L, respectively. All 3 recombinant viral proteins reacted with all 19 samples of NiV-positive human sera. The rNiV-N and rNiV-G proteins were the most immunogenic. The recombinant viral proteins did not react with any of the 12 NiV-negative sera. However, serum from a patient with a late-onset relapsing NiV infection complication was found to be primarily reactive to rNiV-G only. Additionally, there is a distinctive variation in the profile of antigen-reactive bands between the sample from a case of relapsing NiV encephalitis and that of acute NiV infection. The overall findings of this study suggest that the recombinant viral proteins have the potential to be developed further for use in the detection of NiV infection, and continuous biosurveillance of NiV infection in resource-limited settings.

Hendra virus and Nipah virus animal vaccines

Hendra virus (HeV) and Nipah virus (NiV) are zoonotic viruses that emerged in the mid to late 1990s causing disease outbreaks in livestock and people. HeV appeared in Queensland, Australia in 1994 causing a severe respiratory disease in horses along with a human case fatality. NiV emerged a few years later in Malaysia and Singapore in 1998-1999 causing a large outbreak of encephalitis with high mortality in people and also respiratory disease in pigs which served as amplifying hosts. The key pathological elements of HeV and NiV infection in several species of mammals, and also in people, are a severe systemic and often fatal neurologic and/or respiratory disease. In people, both HeV and NiV are also capable of causing relapsed encephalitis following recovery from an acute infection. The known reservoir hosts of HeV and NiV are several species of pteropid fruit bats. Spillovers of HeV into horses continue to occur in Australia and NiV has caused outbreaks in people in Bangladesh and India nearly annually since 2001, making HeV and NiV important transboundary biological threats. NiV in particular possesses several features that underscore its potential as a pandemic threat, including its ability to infect humans directly from natural reservoirs or indirectly from other susceptible animals, along with a capacity of limited human-to-human transmission. Several HeV and NiV animal challenge models have been developed which have facilitated an understanding of pathogenesis and allowed for the successful development of both active and passive immunization countermeasures.

Inhibition of the host antiviral response by Nipah virus: current understanding and future perspectives

Nipah virus (NiV) is a lethal paramyxovirus that has recently emerged as a human pathogen capable of causing acute respiratory disease and encephalitis. Like many viral pathogens, NiV has developed multiple means of antagonizing the host antiviral response. The viral proteins responsible for this antiviral inhibition are encoded in the NiV P gene and include the P, V, W and C proteins, which contain various unique and overlapping roles. This review examines the current data on inhibition of the host antiviral response for each of these proteins gathered from viral protein expression systems, in vitro data using recombinant NiV mutants and from in vivo studies using recombinant NiV mutants, as well as a future perspective regarding the direction of the field.

Detection of Campylobacter jejuni in rectal swab samples from Rousettus amplexicaudatus in the Philippines

Bats are the second diversity species of mammals and widely distributed in the world. They are thought to be reservoir and vectors of zoonotic pathogens. However, there is scarce report of the evidence of pathogenic bacteria kept in bats. The precise knowledge of the pathogenic bacteria in bat microbiota is important for zoonosis control. Thus, metagenomic analysis targeting the V3-V4 region of the 16S rRNA of the rectal microbiota in Rousettus amplexicaudatus was performed using high throughput sequencing. The results revealed that 103 genera of bacteria including Camplyobacter were detected. Campylobacter was second predominant genus, and Campylobacter coli and Campylobacter jejuni were identified in microbiome of R. amplexicaudatus. Campylobacteriosis is one of the serious bacterial diarrhea in human, and the most often implicated species as the causative agent of campylobacteriosis is C. jejuni. Therefore, we investigated the prevalence of C. jejuni in 91 wild bats with PCR. As a result of PCR assay targeted on 16S-23S intergenic spacer, partial genome of C. jejuni was detected only in five R. amplexicaudatus. This is the first report that C. jejuni was detected in bat rectal swab samples. C. jejuni is the most common cause of campylobacteriosis in humans, transmitted through water and contact with livestock animals. This result indicated that R. amplexicaudatus may be a carrier of C. jejuni.

Constraints on the Genetic and Antigenic Variability of Measles Virus

Antigenic drift and genetic variation are significantly constrained in measles virus (MeV). Genetic stability of MeV is exceptionally high, both in the lab and in the field, and few regions of the genome allow for rapid genetic change. The regions of the genome that are more tolerant of mutations (i.e., the untranslated regions and certain domains within the N, C, V, P, and M proteins) indicate genetic plasticity or structural flexibility in the encoded proteins. Our analysis reveals that strong constraints in the envelope proteins (F and H) allow for a single serotype despite known antigenic differences among its 24 genotypes. This review describes some of the many variables that limit the evolutionary rate of MeV. The high genomic stability of MeV appears to be a shared property of the Paramyxovirinae, suggesting a common mechanism that biologically restricts the rate of mutation.

Nipah Virus Transmission from Bats to Humans Associated with Drinking Traditional Liquor Made from Date Palm Sap, Bangladesh, 2011-2014

Nipah virus (NiV) is a paramyxovirus, and Pteropus spp. bats are the natural reservoir. From December 2010 through March 2014, hospital-based encephalitis surveillance in Bangladesh identified 18 clusters of NiV infection. The source of infection for case-patients in 3 clusters in 2 districts was unknown. A team of epidemiologists and anthropologists investigated these 3 clusters comprising 14 case-patients, 8 of whom died. Among the 14 case-patients, 8 drank fermented date palm sap (tari) regularly before their illness, and 6 provided care to a person infected with NiV. The process of preparing date palm trees for tari production was similar to the process of collecting date palm sap for fresh consumption. Bat excreta was reportedly found inside pots used to make tari. These findings suggest that drinking tari is a potential pathway of NiV transmission. Interventions that prevent bat access to date palm sap might prevent tari-associated NiV infection.

Molecular characterization of Nipah virus from Pteropus hypomelanus in Southern Thailand

Background

Nipah virus (NiV) first emerged in Malaysia in 1998, with two bat species (Pteropus hypomelanus and P. vampyrus) as the putative natural reservoirs. In 2002, NiV IgG antibodies were detected in these species from Thailand, but viral RNA could not be detected for strain characterization. Two strains of NiV (Malaysia and Bangladesh) have been found in P. lylei in central Thailand, although Bangladesh strain, the causative strain for the outbreak in Bangladesh since 2001, was dominant. To understand the diversity of NiV in Thailand, this study identified NiV strain, using molecular characterizations, from P. hypomelanus in southern Thailand.

Findings

Pooled bat urine specimens were collected from plastic sheet underneath bat roosts in April 2010, and then monthly from December 2010 to May 2011 at an island in southern Thailand. Five in 184 specimens were positive for NiV, using duplex nested RT-PCR assay on partial nucleocapsid fragment (357 bp). Whole sequences of nucleocapsid gene from four bats were characterized. All 5 partial fragments and 4 whole nucleocapsid genes formed a monophyletic with NiV-MY.

Conclusions

Our study showed that P. hypomelanus in southern Thailand and from Malaysia, a bordering country, harbored similar NiV. This finding indicates that NiV is not limited to central Thailand or P. lylei species, and it may be a source of inter-species transmission. This indicates a higher potential for a widespread NiV outbreak in Thailand. NiV surveillance in Pteropus bats, the major natural reservoirs, should be conducted continuously in countries or regions with high susceptibility to outbreaks.

Wildlife Trade and Human Health in Lao PDR: An Assessment of the Zoonotic Disease Risk in Markets

Although the majority of emerging infectious diseases can be linked to wildlife sources, most pathogen spillover events to people could likely be avoided if transmission was better understood and practices adjusted to mitigate risk. Wildlife trade can facilitate zoonotic disease transmission and represents a threat to human health and economies in Asia, highlighted by the 2003 SARS coronavirus outbreak, where a Chinese wildlife market facilitated pathogen transmission. Additionally, wildlife trade poses a serious threat to biodiversity. Therefore, the combined impacts of Asian wildlife trade, sometimes termed bush meat trade, on public health and biodiversity need assessing. From 2010 to 2013, observational data were collected in Lao PDR from markets selling wildlife, including information on volume, form, species and price of wildlife; market biosafety and visitor origin. The potential for traded wildlife to host zoonotic diseases that pose a serious threat to human health was then evaluated at seven markets identified as having high volumes of trade. At the seven markets, during 21 observational surveys, 1,937 alive or fresh dead mammals (approximately 1,009 kg) were observed for sale, including mammals from 12 taxonomic families previously documented to be capable of hosting 36 zoonotic pathogens. In these seven markets, the combination of high wildlife volumes, high risk taxa for zoonoses and poor biosafety increases the potential for pathogen presence and transmission. To examine the potential conservation impact of trade in markets, we assessed the status of 33,752 animals observed during 375 visits to 93 markets, under the Lao PDR Wildlife and Aquatic Law. We observed 6,452 animals listed by Lao PDR as near extinct or threatened with extinction. The combined risks of wildlife trade in Lao PDR to human health and biodiversity highlight the need for a multi-sector approach to effectively protect public health, economic interests and biodiversity.

Landscape Utilisation, Animal Behaviour and Hendra Virus Risk

Hendra virus causes sporadic fatal disease in horses and humans in eastern Australia. Pteropid bats (flying-foxes) are the natural host of the virus. The mode of flying-fox to horse transmission remains unclear, but oro-nasal contact with flying-fox urine, faeces or saliva is the most plausible. We used GPS data logger technology to explore the landscape utilisation of black flying-foxes and horses to gain new insight into equine exposure risk. Flying-fox foraging was repetitious, with individuals returning night after night to the same location. There was a preference for fragmented arboreal landscape and non-native plant species, resulting in increased flying-fox activity around rural infrastructure. Our preliminary equine data logger study identified significant variation between diurnal and nocturnal grazing behaviour that, combined with the observed flying-fox foraging behaviour, could contribute to Hendra virus exposure risk. While we found no significant risk-exposing difference in individual horse movement behaviour in this study, the prospect warrants further investigation, as does the broader role of animal behaviour and landscape utilisation on the transmission dynamics of Hendra virus.

Henipaviruses

The first henipaviruses, Hendra virus (HeV), and Nipah virus (NiV) were pathogenic zoonoses that emerged in the mid to late 1990s causing serious disease outbreaks in livestock and humans. HeV was recognized in Australia 1994 in horses exhibiting respiratory disease along with a human case fatality, and then NiV was identified during a large outbreak of human cases of encephalitis with high mortality in Malaysia and Singapore in 1998–1999 along with respiratory disease in pigs which served as amplifying hosts. The recently identified third henipavirus isolate, Cedar virus (CedPV), is not pathogenic in animals susceptible to HeV and NiV disease. Molecular detection of additional henipavirus species has been reported but no additional isolates of virus have been reported. Central pathological features of both HeV and NiV infection in humans and several susceptible animal species is a severe systemic and often fatal neurologic and/or respiratory disease. In people, both viruses can also manifest relapsed encephalitis following recovery from an acute infection, particularly NiV. The recognized natural reservoir hosts of HeV, NiV, and CedPV are pteropid bats, which do not show clinical illness when infected. With spillovers of HeV continuing to occur in Australia and NiV in Bangladesh and India, these henipaviruses continue to be important transboundary biological threats. NiV in particular possesses several features that highlight a pandemic potential, such as its ability to infect humans directly from natural reservoirs or indirectly from other susceptible animals along with a capacity of limited human-to-human transmission. Several henipavirus animal challenge models have been developed which has aided in understanding HeV and NiV pathogenesis as well as how they invade the central nervous system, and successful active and passive immunization strategies against HeV and NiV have been reported which target the viral envelope glycoproteins.

The Role of Bats as Reservoir Hosts of Emerging Neuroviruses

Recent studies have clearly shown that bats are the reservoir hosts of a wide diversity of novel viruses with representatives from most of the known animal virus families. In many respects bats make ideal reservoir hosts for viruses: they are the only mammals that fly, thus assisting in virus dispersal; they roost in large numbers, thus aiding transmission cycles; some bats hibernate over winter, thus providing a mechanism for viruses to persist between seasons; and genetic factors may play a role in the ability of bats to host viruses without resulting in clinical disease. Within the broad diversity of viruses found in bats are some important neurological pathogens, including rabies and other lyssaviruses, and Hendra and Nipah viruses, two recently described viruses that have been placed in a new genus, Henipaviruses in the family Paramyxoviridae. In addition, bats can also act as alternative hosts for the flaviviruses Japanese encephalitis and St Louis encephalitis viruses, two important mosquito-borne encephalitogenic viruses, and bats can assist in the dispersal and over-wintering of these viruses. Bats are also the reservoir hosts of progenitors of SARS and MERS coronaviruses, although other animals act as spillover hosts. This chapter presents the physiological and ecological factors affecting the ability of bats to act as reservoirs of neurotropic viruses, and describes the major transmission cycles leading to human infection.

Cloning, expression, and antiviral activity of interferon β from the Chinese microbat, Myotis davidii

Bats are natural reservoir hosts for many viruses that produce no clinical symptoms in bats. Therefore, bats may have evolved effective mechanisms to control viral replication. However, little information is available on bat immune responses to viral infection. Type I interferon (IFN) plays a key role in controlling viral infections. In this study, we report the cloning, expression, and biological activity of interferon β (IFNβ) from the Chinese microbat species, Myotis davidii. We demonstrated the upregulation of IFNB and IFN-stimulated genes in a kidney cell line derived from M. davidii after treatment with polyI:C or infection with Sendai virus. Furthermore, the recombinant IFNβ inhibited vesicular stomatitis virus and bat adenovirus replication in cell lines from two bat species, M. davidii and Rhinolophus sinicus. We provide the first in vitro evidence of IFNβ antiviral activity in microbats, which has important implications for virus interactions with these hosts.

Bats and zoonotic viruses: can we confidently link bats with emerging deadly viruses?

An increasingly asked question is 'can we confidently link bats with emerging viruses?'. No, or not yet, is the qualified answer based on the evidence available. Although more than 200 viruses - some of them deadly zoonotic viruses - have been isolated from or otherwise detected in bats, the supposed connections between bats, bat viruses and human diseases have been raised more on speculation than on evidence supporting their direct or indirect roles in the epidemiology of diseases (except for rabies). However, we are convinced that the evidence points in that direction and that at some point it will be proved that bats are competent hosts for at least a few zoonotic viruses. In this review, we cover aspects of bat biology, ecology and evolution that might be relevant in medical investigations and we provide a historical synthesis of some disease outbreaks causally linked to bats. We provide evolutionary-based hypotheses to tentatively explain the viral transmission route through mammalian intermediate hosts and to explain the geographic concentration of most outbreaks, but both are no more than speculations that still require formal assessment.

Henipavirus Encephalitis: Recent Developments and Advances

The genus Henipavirus within the family Paramyxoviridae includes the Hendra virus (HeV) and Nipah virus (NiV) which were discovered in the 1990s in Australia and Malaysia, respectively, after emerging to cause severe and often fatal outbreaks in humans and animals. While HeV is confined to Australia, more recent NiV outbreaks have been reported in Bangladesh, India and the Philippines. The clinical manifestations of both henipaviruses in humans appear similar, with a predominance of an acute encephalitic syndrome. Likewise, the pathological features are similar and characterized by disseminated, multi-organ vasculopathy comprising endothelial infection/ulceration, vasculitis, vasculitis-induced thrombosis/occlusion, parenchymal ischemia/microinfarction, and parenchymal cell infection in the central nervous system (CNS), lung, kidney and other major organs. This unique dual pathogenetic mechanism of vasculitis-induced microinfarction and neuronal infection causes severe tissue damage in the CNS. Both viruses can also cause relapsing encephalitis months and years after the acute infection. Many animal models studied to date have largely confirmed the pathology of henipavirus infection, and provided the means to test new therapeutic agents and vaccines. As the bat is the natural host of henipaviruses and has worldwide distribution, spillover events into human populations are expected to occur in the future.

Zoonotic Viruses and Conservation of Bats

Many of the recently emerging highly virulent zoonotic diseases have a likely bat origin, for example Hendra, Nipah, Ebola and diseases caused by coronaviruses. Presumably because of their long history of coevolution, most of these viruses remain subclinical in bats, but have the potential to cause severe illnesses in domestic and wildlife animals and also humans. Spillovers from bats to humans either happen directly (via contact with infected bats) or indirectly (via intermediate hosts such as domestic or wildlife animals, by consuming food items contaminated by saliva, faeces or urine of bats, or via other environmental sources). Increasing numbers of breakouts of zoonotic viral diseases among humans and livestock have mainly been accounted to human encroachment into natural habitat, as well as agricultural intensification, deforestation and bushmeat consumption. Persecution of bats, including the destruction of their roosts and culling of whole colonies, has led not only to declines of protected bat species, but also to an increase in virus prevalence in some of these populations. Educational efforts are needed in order to prevent future spillovers of bat-borne viruses to humans and livestock, and to further protect bats from unnecessary and counterproductive culling.

Network analysis of host-virus communities in bats and rodents reveals determinants of cross-species transmission

Bats are natural reservoirs of several important emerging viruses. Cross‐species transmission appears to be quite common among bats, which may contribute to their unique reservoir potential. Therefore, understanding the importance of bats as reservoirs requires examining them in a community context rather than concentrating on individual species. Here, we use a network approach to identify ecological and biological correlates of cross‐species virus transmission in bats and rodents, another important host group. We show that given our current knowledge the bat viral sharing network is more connected than the rodent network, suggesting viruses may pass more easily between bat species. We identify host traits associated with important reservoir species: gregarious bats are more likely to share more viruses and bats which migrate regionally are important for spreading viruses through the network. We identify multiple communities of viral sharing within bats and rodents and highlight potential species traits that can help guide studies of novel pathogen emergence.

Origin and evolution of Nipah virus

Nipah virus, member of the Paramyxoviridae family, is classified as a Biosafety Level-4 agent and category C priority pathogen. Nipah virus disease is endemic in south Asia and outbreaks have been reported in Malaysia, Singapore, India, and Bangladesh. Bats of the genus Pteropus appear to be the natural reservoir of this virus. The aim of this study was to investigate the genetic diversity of Nipah virus, to estimate the date of origin and the spread of the infection. The mean value of Nipah virus N gene evolutionary rate, was 6.5 × 10(-4) substitution/site/year (95% HPD: 2.3 × 10(-4)-1.18 × 10(-3)). The time-scaled phylogenetic analysis showed that the root of the tree originated in 1947 (95% HPD: 1888-1988) as the virus entered in south eastern Asiatic regions. The segregation of sequences in two main clades (I and II) indicating that Nipah virus had two different introductions: one in 1995 (95% HPD: 1985-2002) which correspond to clade I, and the other in 1985 (95% HPD: 1971-1996) which correspond to clade II. The phylogeographic reconstruction indicated that the epidemic followed two different routes spreading to the other locations. The trade of infected pigs may have played a role in the spread of the virus. Bats of the Pteropus genus, that are able to travel to long distances, may have contributed to the spread of the infection. Negatively selected sites, statistically supported, could reflect the stability of the viral N protein.

Immunology of bats and their viruses: challenges and opportunities

Bats are reservoir hosts of several high-impact viruses that cause significant human diseases, including Nipah virus, Marburg virus and rabies virus. They also harbor many other viruses that are thought to have caused disease in humans after spillover into intermediate hosts, including SARS and MERS coronaviruses. As is usual with reservoir hosts, these viruses apparently cause little or no pathology in bats. Despite the importance of bats as reservoir hosts of zoonotic and potentially zoonotic agents, virtually nothing is known about the host/virus relationships; principally because few colonies of bats are available for experimental infections, a lack of reagents, methods and expertise for studying bat antiviral responses and immunology, and the difficulty of conducting meaningful field work. These challenges can be addressed, in part, with new technologies that are species-independent that can provide insight into the interactions of bats and viruses, which should clarify how the viruses persist in nature, and what risk factors might facilitate transmission to humans and livestock.

Bats as reservoirs of severe emerging infectious diseases

In recent years severe infectious diseases have been constantly emerging, causing panic in the world. Now we know that many of these terrible diseases are caused by viruses originated from bats (Table 1), such as Ebola virus, Marburg, SARS coronavirus (SARS-CoV), MERS coronavirus (MERS-CoV), Nipah virus (NiV) and Hendra virus (HeV). These viruses have co-evolved with bats due to bats' special social, biological and immunological features. Although bats are not in close contact with humans, spillover of viruses from bats to intermediate animal hosts, such as horses, pigs, civets, or non-human primates, is thought to be the most likely mode to cause human infection. Humans may also become infected with viruses through aerosol by intruding into bat roosting caves or via direct contact with bats, such as catching bats or been bitten by bats.

Spatial characterization of colonies of the flying fox bat, a carrier of Nipah virus in Thailand

Background

A major reservoir of Nipah virus is believed to be the flying fox genus Pteropus, a fruit bat distributed across many of the world’s tropical and sub-tropical areas. The emergence of the virus and its zoonotic transmission to livestock and humans have been linked to losses in the bat’s habitat. Nipah has been identified in a number of indigenous flying fox populations in Thailand. While no evidence of infection in domestic pigs or people has been found to date, pig farming is an active agricultural sector in Thailand and therefore could be a potential pathway for zoonotic disease transmission from the bat reservoirs. The disease, then, represents a potential zoonotic risk. To characterize the spatial habitat of flying fox populations along Thailand’s Central Plain, and to map potential contact zones between flying fox habitats, pig farms and human settlements, we conducted field observation, remote sensing, and ecological niche modeling to characterize flying fox colonies and their ecological neighborhoods. A Potential Surface Analysis was applied to map contact zones among local epizootic actors.

Results

Flying fox colonies are found mainly on Thailand’s Central Plain, particularly in locations surrounded by bodies of water, vegetation, and safe havens such as Buddhist temples. High-risk areas for Nipah zoonosis in pigs include the agricultural ring around the Bangkok metropolitan region where the density of pig farms is high.

Conclusions

Passive and active surveillance programs should be prioritized around Bangkok, particularly on farms with low biosecurity, close to water, and/or on which orchards are concomitantly grown. Integration of human and animal health surveillance should be pursued in these same areas. Such proactive planning would help conserve flying fox colonies and should help prevent zoonotic transmission of Nipah and other pathogens.

How to reach the poor? Surveillance in low-income countries, lessons from experiences in Cambodia and Madagascar

Surveillance of animal diseases in developing countries faces many constraints. Innovative tools and methods to enhance surveillance in remote and neglected areas should be defined, assessed and applied in close connection with local farmers, national stakeholders and international agencies. The authors performed a narrative synthesis of their own publications about surveillance in Madagascar and Cambodia. They analysed the data in light of their fieldwork experiences in the two countries' very challenging environments. The burden of animal and zoonotic diseases (e.g. avian influenza, African swine fever, Newcastle disease, Rift Valley fever) is huge in both countries which are among the poorest in the world. Being poor countries implies a lack of human and financial means to ensure effective surveillance of emerging and endemic diseases. Several recent projects have shown that new approaches can be proposed and tested in the field. Several advanced participatory approaches are promising and could be part of an innovative method for improving the dialogue among different actors in a surveillance system. Thus, participatory modelling, developed for natural resources management involving local stakeholders, could be applied to health management, including surveillance. Data transmission could benefit from the large mobile-phone coverage in these countries. Ecological studies and advances in the field of livestock surveillance should guide methods for enhancing wildlife monitoring and surveillance. Under the umbrella of the One Health paradigm, and in the framework of a risk-based surveillance concept, a combination of participatory methods and modern technologies could help to overcome the constraints present in low-income countries. These unconventional approaches should be merged in order to optimise surveillance of emerging and endemic diseases in challenging environments.

Analysis of cathepsin and furin proteolytic enzymes involved in viral fusion protein activation in cells of the bat reservoir host

Bats of different species play a major role in the emergence and transmission of highly pathogenic viruses including Ebola virus, SARS-like coronavirus and the henipaviruses. These viruses require proteolytic activation of surface envelope glycoproteins needed for entry, and cellular cathepsins have been shown to be involved in proteolysis of glycoproteins from these distinct virus families. Very little is currently known about the available proteases in bats. To determine whether the utilization of cathepsins by bat-borne viruses is related to the nature of proteases in their natural hosts, we examined proteolytic processing of several viral fusion proteins in cells derived from two fruit bat species, Pteropus alecto and Rousettus aegyptiacus. Our work shows that fruit bat cells have homologs of cathepsin and furin proteases capable of cleaving and activating both the cathepsin-dependent Hendra virus F and the furin-dependent parainfluenza virus 5 F proteins. Sequence analysis comparing Pteropus alecto furin and cathepsin L to proteases from other mammalian species showed a high degree of conservation; however significant amino acid variation occurs at the C-terminus of Pteropus alecto furin. Further analysis of furin-like proteases from fruit bats revealed that these proteases are catalytically active and resemble other mammalian furins in their response to a potent furin inhibitor. However, kinetic analysis suggests that differences may exist in the cellular localization of furin between different species. Collectively, these results indicate that the unusual role of cathepsin proteases in the life cycle of bat-borne viruses is not due to the lack of active furin-like proteases in these natural reservoir species; however, differences may exist between furin proteases present in fruit bats compared to furins in other mammalian species, and these differences may impact protease usage for viral glycoprotein processing.

Detailed analysis of the African green monkey model of Nipah virus disease

Henipaviruses are implicated in severe and frequently fatal pneumonia and encephalitis in humans. There are no approved vaccines or treatments available for human use, and testing of candidates requires the use of well-characterized animal models that mimic human disease. We performed a comprehensive and statistically-powered evaluation of the African green monkey model to define parameters critical to disease progression and the extent to which they correlate with human disease. African green monkeys were inoculated by the intratracheal route with 2.5 × 10(4) plaque forming units of the Malaysia strain of Nipah virus. Physiological data captured using telemetry implants and assessed in conjunction with clinical pathology were consistent with shock, and histopathology confirmed widespread tissue involvement associated with systemic vasculitis in animals that succumbed to acute disease. In addition, relapse encephalitis was identified in 100% of animals that survived beyond the acute disease phase. Our data suggest that disease progression in the African green monkey is comparable to the variable outcome of Nipah virus infection in humans.

Animal models of disease shed light on Nipah virus pathogenesis and transmission

Nipah virus is an emerging virus infection that causes yearly disease outbreaks with high case fatality rates in Bangladesh. Nipah virus causes encephalitis and systemic vasculitis, sometimes in combination with respiratory disease. Pteropus species fruit bats are the natural reservoir of Nipah virus and zoonotic transmission can occur directly or via an intermediate host; human-to-human transmission occurs regularly. In this review we discuss the current state of knowledge on the pathogenesis and transmission of Nipah virus, focusing on dissemination of the virus through its host, known determinants of pathogenicity and routes of zoonotic and human-to-human transmission. Since data from human cases are sparse, this knowledge is largely based on the results of studies performed in animal models that recapitulate Nipah virus disease in humans.

Exposure-based screening for Nipah virus encephalitis, Bangladesh

We measured the performance of exposure screening questions to identify Nipah virus encephalitis in hospitalized encephalitis patients during the 2012-13 Nipah virus season in Bangladesh. The sensitivity (93%), specificity (82%), positive predictive value (37%), and negative predictive value (99%) results suggested that screening questions could more quickly identify persons with Nipah virus encephalitis.

A Review of Hendra Virus and Nipah Virus Infections in Man and Other Animals

Hendra virus (HeV) and Nipah virus (NiV) emerged in the last decade of the twentieth century. They were the cause of a number of outbreaks of respiratory and neurological disease infecting horses and pigs respectively. Transmission from infected domestic animal species resulted in human infections as well, with high case fatality rates a feature. Today they continue to cause outbreaks of human and animal disease. NiV causes yearly disease outbreaks in humans in Bangladesh, and HeV causes sporadic disease outbreaks in horses in north eastern Australia. Due to their zoonotic nature, they have been ideal candidates for collaborative projects in the One Health space, bringing public health and animal health professionals together. This has lead to insightful epidemiological studies, which has resulted in practical disease prevention solutions including a horse vaccine for HeV and NiV spill-over prevention interventions in the field. As more surveillance is undertaken, their known distributions have expanded, as has the range of reservoir host species. The majority of bat species for which there is evidence of henipavirus infection belong to the group known as the Old World family of fruit and nectar feeding bats (Family Pteropodidae, Suborder Megachiroptera). This review of the bat borne henipaviruses discusses the epidemiology, pathology, transmission and disease symptoms in these closely related viruses which belong to the Genus Henipavirus, Family Paramyxoviridae.

Birth and pathogenesis of rogue respiratory viruses

Emerging infectious diseases of zoonotic origin are shaping today's infectious disease field more than ever. In this article, we introduce and review three emerging zoonotic viruses. Novel hantaviruses emerged in the Americas in the mid-1990s as the cause of severe respiratory infections, designated hantavirus pulmonary syndrome, with case fatality rates of around 40%. Nipah virus emerged a few years later, causing respiratory infections and encephalitis in Southeast Asia, with case fatality rates ranging from 40% to more than 90%. A new coronavirus emerged in 2012 on the Arabian Peninsula with a clinical syndrome of acute respiratory infections, later designated as Middle East respiratory syndrome (MERS), and an initial case fatality rate of more than 40%. Our current state of knowledge on the pathogenicity of these three severe, emerging viral infections is discussed.

Serological evidence of henipavirus exposure in cattle, goats and pigs in Bangladesh

Background

Nipah virus (NiV) is an emerging disease that causes severe encephalitis and respiratory illness in humans. Pigs were identified as an intermediate host for NiV transmission in Malaysia. In Bangladesh, NiV has caused recognized human outbreaks since 2001 and three outbreak investigations identified an epidemiological association between close contact with sick or dead animals and human illness.

Methodology

We examined cattle and goats reared around Pteropus bat roosts in human NiV outbreak areas. We also tested pig sera collected under another study focused on Japanese encephalitis.

Principal Findings

We detected antibodies against NiV glycoprotein in 26 (6.5%) cattle, 17 (4.3%) goats and 138 (44.2%) pigs by a Luminex-based multiplexed microsphere assay; however, these antibodies did not neutralize NiV. Cattle and goats with NiVsG antibodies were more likely to have a history of feeding on fruits partially eaten by bats or birds (PR = 3.1, 95% CI 1.6–5.7) and drinking palmyra palm juice (PR = 3.9, 95% CI 1.5–10.2).

Conclusions

This difference in test results may be due to the exposure of animals to one or more novel viruses with antigenic similarity to NiV. Further research may identify a novel organism of public health importance.

Nipah virus (NiV), is an emerging disease that causes severe encephalitis and respiratory illness in humans. Pigs were identified as an intermediate host for NiV transmission in Malaysia, and in Bangladesh three NiV outbreak investigations since 2001 identified an epidemiological association between close contact with sick or dead animals and human illness. We collected samples from cattle and goats reared around Pteropus bat roosts in human NiV outbreak areas in Bangladesh, and tested pig sera collected for a Japanese encephalitis study. We detected antibodies against NiV glycoprotein in 26 (6.5%) cattle, 17 (4.3%) goats and 138 (44.2%) pigs by a Luminex-based multiplexed microsphere assay, but none were virus neutralizing. There may have been exposure of Luminex positive animals to one or more novel viruses with antigenic similarity to NiV. Further research may identify a novel organism of public health importance.