"Why won't they just vaccinate?" Horse owner risk perception and uptake of the Hendra virus vaccine

Biosecurity perceptions among Ontario horse owners during the COVID-19 pandemic

BACKGROUND

Disease outbreaks present a significant challenge to horse health and welfare and the economic stability of horse industries internationally. This is a particular concern in Ontario, Canada, where there have been frequent outbreaks of respiratory infectious diseases among horses. Despite these risks, there has been limited research on whether Ontario horse owners engage in biosecurity measures sufficient to mitigate risk of equine diseases, and whether current events such as the COVID-19 pandemic influence attitudes towards equine biosecurity practices.

OBJECTIVE

To explore Ontario horse owners' perceptions, attitudes and experiences relating to on-farm biosecurity during the COVID-19 pandemic.

STUDY DESIGN

Qualitative study using virtual semi-structured interviews.

METHODS

Participants (horse owners, frequent horse riders and part boarders) were recruited using social media snowball sampling where advertisements were shared by equine and veterinary organisations. Interviews were conducted virtually between June and September 2022 and were analysed using reflexive thematic analysis.

RESULTS

Three key themes relating to biosecurity perceptions among the 14 participants were identified. Participants relied on minimal preventative measures (such as vaccines) where perceived risk of disease was low, but implemented additional measures including quarantine and handwashing when perceived risk of disease was high. Participants' choice of biosecurity practices often mirrored those recommended by the barn manager. Moreover, participants felt that responsibility for biosecurity was not shared equally across horse owners, with more emphasis placed on those engaging in high-risk situations for disease spread. Despite experiencing biosecurity during the COVID-19 pandemic, horse owners were not consistently applying these practices to their horse care routines.

MAIN LIMITATIONS

The perspectives reported here are from a small sample of horse owners and may not be generalisable to all populations.

CONCLUSIONS

Our findings indicate that horse owners need improved access to and engagement with educational initiatives that emphasise the importance and purpose of all biosecurity measures.

Perceptions of Sheep Farmers and District Veterinarians towards Sheep Disease Management in New South Wales, Australia

The study objectives were to understand the practices and perceptions of sheep farmers and district veterinarians (DVs) towards sheep health management and, the impact of disease at the farm level in addition to the availability, accessibility, and use of veterinary services. Data were collected using question-based surveys, distributed online and in-person to sheep farmers (45 respondents) and DVs (25 respondents). Most farmers were male, ≥51 years old, who placed a high priority on the health and welfare of their sheep. For disease prevention most farmers vaccinated their sheep (91%) and 86.7% had a farm biosecurity plan, although its components and their application varied, e.g., the isolation of new or sick sheep. Fencing costs were most frequently identified (70.5% respondents) as a financial concern for sheep farmers. Their most common sources of information about disease control and prevention were DVs (66.7%), private veterinarians (60.0%), the internet (42.9%), rural suppliers (35.7%), and farmers/neighbours (28.6%). Fifty-eight percent of farmers reported a long distance from veterinarian services. Farmers preferred to receive information via email (77.8%), whereas 56% of DVs preferred to share information via phone call. This discrepancy presents an opportunity to align these mechanisms more closely for effective dissemination of information and increased producer engagement.

Organising for One Health in a developing country

Globally, zoonotic diseases pose an enormous and growing public health challenge, and developing countries like India are at the epicentre of it. Although there is general recognition of this reality, governments around the world have struggled to organise appropriately to respond to it. The widely held view is that organising for One Health requires effective cross-sectoral collaboration, but the prerequisites to enable such collaboration appear almost unattainable. Perhaps an entirely different approach is needed, which is over and above effective collaborations between competing government ministries. The approach would have to recognise that while any organisational response will need to be able to address identified zoonotic diseases and respond effectively to them in times of crises, it would also be required to have the ability to shape the response to megatrends such as climate change, deforestation, and the underlying development models of the country. The paper analyses the success and failures associated with the way in which India, Bangladesh, Kenya, and Rwanda have organised for One Health. It also studies the underlying pathways through which zoonotic spillovers take place, and epidemics gather momentum. Based on these critical analyses, the paper concludes that attempts to build single overarching units to address these challenges have only been partially effective. Given the scale and complexity of the challenge, it recommends that, even at the risk of duplication and the very real possibility that unaddressed gaps will remain, an approach, which builds multiple sharply focused units, would have a greater chance of success.

Policies to prevent zoonotic spillover: a systematic scoping review of evaluative evidence

BACKGROUND

Emerging infectious diseases of zoonotic origin present a critical threat to global population health. As accelerating globalisation makes epidemics and pandemics more difficult to contain, there is a need for effective preventive interventions that reduce the risk of zoonotic spillover events. Public policies can play a key role in preventing spillover events. The aim of this review is to identify and describe evaluations of public policies that target the determinants of zoonotic spillover. Our approach is informed by a One Health perspective, acknowledging the inter-connectedness of human, animal and environmental health.

METHODS

In this systematic scoping review, we searched Medline, SCOPUS, Web of Science and Global Health in May 2021 using search terms combining animal health and the animal-human interface, public policy, prevention and zoonoses. We screened titles and abstracts, extracted data and reported our process in line with PRISMA-ScR guidelines. We also searched relevant organisations' websites for evaluations published in the grey literature. All evaluations of public policies aiming to prevent zoonotic spillover events were eligible for inclusion. We summarised key data from each study, mapping policies along the spillover pathway.

RESULTS

Our review found 95 publications evaluating 111 policies. We identified 27 unique policy options including habitat protection; trade regulations; border control and quarantine procedures; farm and market biosecurity measures; public information campaigns; and vaccination programmes, as well as multi-component programmes. These were implemented by many sectors, highlighting the cross-sectoral nature of zoonotic spillover prevention. Reports emphasised the importance of surveillance data in both guiding prevention efforts and enabling policy evaluation, as well as the importance of industry and private sector actors in implementing many of these policies. Thoughtful engagement with stakeholders ranging from subsistence hunters and farmers to industrial animal agriculture operations is key for policy success in this area.

CONCLUSION

This review outlines the state of the evaluative evidence around policies to prevent zoonotic spillover in order to guide policy decision-making and focus research efforts. Since we found that most of the existing policy evaluations target 'downstream' determinants, additional research could focus on evaluating policies targeting 'upstream' determinants of zoonotic spillover, such as land use change, and policies impacting infection intensity and pathogen shedding in animal populations, such as those targeting animal welfare.

Langya virus outbreak: current challenges and lesson learned from previous henipavirus outbreaks in China, Australia, and Southeast Asia

Background and aims

A new novel virus, Langya virus (LayV), was detected in China in August 2022, 3 years after the COVID-19 pandemic. LayV is similar to the previously discovered Mojiang henipavirus. Other zoonotic henipaviruses include the Hendra and Nipah viruses. The emergence of the zoonotic Langya virus is attributed to climate change and wildlife encroachment, as LayV is detected in shrews. Those who are infected in China showed various symptoms, but no deaths have been recorded yet. This review aims to shed light on the current state of Langya virus outbreak, its infection control efforts, and the remaining challenges that need to be addressed to curb the outbreak.

Methods

We utilized online publication databases such as PubMed, Google Scholar, and Scopus in writing this review article.

Results

A surveillance study on thirty-five febrile patients in Eastern China identified the Langya virus outbreak. The current efforts from the Chinese government and health authorities to reduce the transmission and spread of Langya virus such as isolation and characterization of LayV, challenges associated with the increase in cases of LayV, and trackable recommendations such as strengthening the healthcare system in China, sensitization of people about risks associated with Langya virus outbreaks, creating an intensive surveillance system network, etc. were discussed.

Conclusion

It is germane and pertinent that the Chinese government and health authorities continue to intensify efforts against Langya virus and address the challenges to effectively reduce transmission.

Communication Interventions and Assessment of Drivers for Hendra Virus Vaccination Uptake

Hendra virus disease (HeVD) is an emerging zoonosis in Australia, resulting from the transmission of Hendra virus (HeV) to horses from Pteropus bats. Vaccine uptake for horses is low despite the high case fatality rate of HeVD in both horses and people. We reviewed evidence-based communication interventions to promote and improve HeV vaccine uptake for horses by horse owners and conducted a preliminary evaluation of potential drivers for HeV vaccine uptake using the Behavioural and Social Drivers of Vaccination (BeSD) framework developed by the World Health Organization. Six records were eligible for review following a comprehensive search and review strategy of peer-reviewed literature, but evidence-based communication interventions to promote and improve HeV vaccine uptake for horses were lacking. An evaluation of potential drivers for HeV vaccine uptake using the BeSD framework indicated that horse owners' perceptions, beliefs, social processes, and practical issues are similar to those experienced by parents making decisions about childhood vaccines, although the overall motivation to vaccinate is lower amongst horse owners. Some aspects of HeV vaccine uptake are not accounted for in the BeSD framework (for example, alternative mitigation strategies such as covered feeding stations or the zoonotic risk of HeV). Overall, problems associated with HeV vaccine uptake appear well-documented. We, therefore, propose to move from a problems-focused to a solutions-focused approach to reduce the risk of HeV for humans and horses. Following our findings, we suggest that the BeSD framework could be modified and used to develop and evaluate communication interventions to promote and improve HeV vaccine uptake by horse owners, which could have a global application to promote vaccine uptake for other zoonotic diseases in animals, such as rabies.

Hendra Virus: An Update on Diagnosis, Vaccination, and Biosecurity Protocols for Horses

Hendra virus (HeV) emerged as a zoonotic pathogen in the 1990s, causing low morbidity but high mortality in humans and horses. Pteropid bats are the natural reservoir of HeV and other important zoonotic viruses such as Nipah and Ebola viruses. Equivac HeV, manufactured by Zoetis (Parkville, Victoria, Australia), is the only commercially available vaccine for horses. There is no commercial vaccine for humans. The epidemiology, clinical features, pathology, diagnosis, management, and prevention of HeV will be reviewed.

Implementation of biosecurity on equestrian premises: A narrative overview

Biosecurity measures are designed to prevent the introduction and spread of pathogens, and play a vital role in the equine industry, controlling endemic diseases and reducing the threat of exotic disease incursion. Equestrian premises differ with respect to disease risks, biosecurity requirements and available facilities. This narrative review summarises reported frequency of implementation for selected biosecurity measures, as well as evidence relating to potential barriers to implementation of biosecurity on equestrian premises. Possible opportunities for improvement in the adoption of equine biosecurity measures are also discussed.

Willingness to adopt personal biosecurity strategies on thoroughbred breeding farms: Findings from a multi-site pilot study in Australia's Hunter Valley

There are almost 9,500 full-time employees in Australia's thoroughbred horse breeding industry. During foaling, they can be exposed to bodily fluids and mucous membranes which may present risks for zoonotic disease. These risks can be mitigated through personal biosecurity strategies. The aim of this study was to identify which personal biosecurity strategies were more or less likely to be adopted by workers. Seventeen participants representing 14 thoroughbred breeding farms and three equine veterinary practices in Australia's largest thoroughbred breeding region trialed up to 16 stakeholder-nominated personal biosecurity strategies over the 2021 foaling season. The strategies encompassed personal protective equipment (PPE), zoonotic disease awareness, policies and protocols, supportive environments, and leadership. Strategy adoption was monitored through three repeated self-audit surveys designed around the Transtheoretical Model of change (TTM) and findings were reviewed in exit interviews. For all survey waves in aggregate, 13 strategies were practiced by at least 50.0% of participants. Participants were most likely to use a ready-made foaling box (98.0%), communicate the message that PPE usage is a personal responsibility (94.1%) and use ready-made PPE kits (88.2%). However, 31.4% had no intention of doing practice sessions and/or dummy runs for PPE use and 27.5% had no intention of using a buddy system on farm/practice to check use of PPE. Whilst these rates indicate workers' willingness to adopt and maintain personal biosecurity strategies, they also indicate capacity for more practices to be implemented more often. Overall, the findings highlight the need for personal biosecurity interventions to be sensitive to the demands of the annual thoroughbred breeding calendar, the size of the breeding operation and the availability of skilled staff.

Novel variant Hendra virus genotype 2 infection in a horse in the greater Newcastle region, New South Wales, Australia

In October 2021, the first contemporary detection of Hendra virus genotype 2 (HeV-g2) was made by veterinary priority disease investigation in a horse near Newcastle, New South Wales, Australia, as part of routine veterinary priority disease surveillance.

This discovery followed an update of Hendra virus diagnostic assays following retrospective identification of this variant from 2015 via sentinel emerging infectious disease research, enabling timely detection of this case. The sole infected horse was euthanized in moribund condition. As the southernmost recognised HeV spill-over detection to date, it extends the southern limit of known cases by approximately 95 km. The event occurred near a large urban centre, characterised by equine populations of diverse type, husbandry, and purpose, with low HeV vaccination rates.

Urgent multi-agency outbreak response involved risk assessment and monitoring of 11 exposed people and biosecurity management of at-risk animals. No human or additional animal cases were recognised.

This One Health investigation highlights need for research on risk perception and strategic engagement to support owners confronted with the death of companion animals and potential human exposure to a high consequence virus. The location and timing of this spill-over event diverging from that established for prototype HeV (HeV-g1), highlight benefit in proactive One Health surveillance and research activities that improve understanding of dynamic transmission and spill-over risks of both HeV genotypic lineages and related but divergent emerging pathogens.

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In October 2021 an equine case of Hendra virus genotype 2 (HeV-g2) was detected near Newcastle, Australia

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Detection was facilitated through recent adoption by animal health of an updated PCR assay able to detect HeV-g2

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The case occurred outside of the southern winter season typical for HeV and marks the southernmost equine detection to date

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This event highlights the expanded geographical risk of spillover from flying-foxes to horses that is presented by HeV-g2

Serological Hendra Virus Diagnostics Using an Indirect ELISA-Based DIVA Approach with Recombinant Hendra G and N Proteins

Since the identification of Hendra virus (HeV) infections in horses in Australia in 1994, more than 80 outbreaks in horses have been reported, and four out of seven spillover infections in humans had a fatal outcome. With the availability of a subunit vaccine based on the HeV-Glycoprotein (HeV-G), there is a need to serologically Differentiate the Infected from the Vaccinated Animals (DIVA). We developed an indirect ELISA using HeV-G expressed in Leishmania tarentolae and HeV-Nucleoprotein (HeV-N) expressed in recombinant baculovirus-infected insect cells as antigens. During evaluation, we tested panels of sera from naïve, vaccinated and infected horses that either originated from a Hendra-virus free region, or had been pre-tested in validated diagnostic tests. Our data confirm the reliability of this approach, as HeV-N-specific antibodies were only detected in sera from infected horses, while HeV-G-specific antibodies were detected in infected and vaccinated horses with a high level of specificity and sensitivity. Given the excellent correlation of data obtained for German and Australian HeV-negative horses, we assume that this test can be applied for the testing of horse serum samples from a variety of geographical regions.

Henipaviruses-A constant threat to livestock and humans

In this review, we highlight the risk to livestock and humans from infections with henipaviruses, which belong to the virus family Paramyxoviridae. We provide a comprehensive overview of documented outbreaks of Nipah and Hendra virus infections affecting livestock and humans and assess the burden on the economy and health systems. In an increasingly globalized and interconnected world, attention must be paid to emerging viruses and infectious diseases, as transmission routes can be rapid and worldwide.

Development and validation of an IgM antibody capture ELISA for early detection of Hendra virus

Zoonotic transmission of Hendra virus (HeV) from primary hosts (pteropid bats) to horses, and, occasionally, onward adventitious spread to humans, is associated with high mortality rates in both affected secondary species. The introduction of an effective recombinant G protein vaccine for use in horses has been a major advance for the suppression of disease risk. However, equine HeV vaccination induces neutralising antibody that is indistinguishable from a post infection immune response when using most first line serology assays (eg. VNT and some ELISAs). We have constructed and evaluated an IgM antibody capture (MAC) ELISA which employs yeast expressed HeV nucleoprotein (N). All other serology tests use the G protein which does not detect early infection and is present in the current Hendra virus vaccine and may cause ambiguity in interpretation of results. Thus, this is the first test developed using a N protein which can successfully detect a recent (primarily within the last four weeks) infection of horses with HeV and is not affected by vaccination induced antibody. Testing a limited panel (21 samples) of post infection sera, a normal serum panel (288 samples) and a post vaccination panel (163 samples), we have estimated DSe to be 100 % (95 % CI, 83.9-100.0 %) and DSp to be 98.4 % (95 % CI, 96.8-99.4 %) relative to assigned serology results (VNT, ELISA and Luminex) for the test panels. The HeV IgM MAC ELISA is intended to supplement other molecular and serology test results, with selective use, and is the only serology test which can provide an indication for recent infection which is otherwise not available.

Sero-Monitoring of Horses Demonstrates the Equivac® HeV Hendra Virus Vaccine to Be Highly Effective in Inducing Neutralising Antibody Titres

Hendra virus (HeV) is a high consequence zoonotic pathogen found in Australia. The HeV vaccine was developed for use in horses and provides a One Health solution to the prevention of human disease. By protecting horses from infection, the vaccine indirectly protects humans as well, as horses are the only known source of infection for humans. The sub-unit-based vaccine, containing recombinant HeV soluble G (sG) glycoprotein, was released by Pfizer Animal Health (now Zoetis) for use in Australia at the end of 2012. The purpose of this study was to collate post-vaccination serum neutralising antibody titres as a way of assessing how the vaccine has been performing in the field. Serum neutralization tests (SNTs) were performed on serum samples from vaccinated horses submitted to the laboratory by veterinarians. The SNT results have been analysed, together with age, dates of vaccinations, date of sampling and location. Results from 332 horses formed the data set. Provided horses received at least three vaccinations (consisting of two doses 3–6 weeks apart, and a third dose six months later), horses had high neutralising titres (median titre for three or more vaccinations was 2048), and none tested negative.

The Hendra virus vaccine: perceptions regarding the role of antibody titre testing

OBJECTIVES

To elucidate veterinarians' and horse owners' perceptions towards the use of Hendra virus (HeV) antibody titre testing and how it influences veterinary advice.

METHODS

Six semi-structured phone interviews were conducted with veterinarians who have submitted samples for HeV antibody titre testing. Interviews were recorded, transcribed and thematically analysed to identify and report common themes within the data.

RESULTS

Veterinarians are predominantly using the titre tests as an alternative to vaccination due to clients' fear of vaccine reactions. The high cost of titre testing, the difficulty interpreting titre results and a lack of titre test recognition by authorities were the major barriers reported to using this test. Some veterinarians detailed difficulties communicating titre test procedures and results to their clients. The majority of veterinarians accepted titres of 64 or greater as evidence of protective immunity and would rely on those results for 12 months. However, there was discrepancy of these values and the level of confidence veterinarians had in interpreting the results of HeV antibody titre tests varied.

CONCLUSION

This study has provided an overview of the attitudes of horse owners and veterinarians towards HeV antibody titre testing. Although evidence for HeV vaccination titres as an indication of protective immunity is still inadequate, it will assist veterinarians in interpreting and communicating titre results.

Using a Bayesian Network Predictive Model to Understand Vulnerability of Australian Sheep Producers to a Foot and Mouth Disease Outbreak

To maintain and strengthen Australia's competitive international advantage in sheep meat and wool markets, the biosecurity systems that support these industries need to be robust and effective. These systems, strengthened by jurisdictional and livestock industry investments, can also be enhanced by a deeper understanding of individual producer risk of exposure to animal diseases and capacity to respond to these risks. This observational study developed a Vulnerability framework, built from current data from Australian sheep producers around behaviors and beliefs that may impact on their likelihood of Exposure and Response Capacity (willingness and ability to respond) to an emergency animal disease (EAD). Using foot and mouth disease (FMD) as a model, a cross-sectional survey gathered information on sheep producers' demographics, and their practices and beliefs around animal health management and biosecurity. Using the Vulnerability framework, a Bayesian Network (BN) model was developed as a first attempt to develop a decision making tool to inform risk based surveillance resource allocation. Populated by the data from 448 completed questionnaires, the BN model was analyzed to investigate relationships between variables and develop producer Vulnerability profiles. Respondents reported high levels of implementation of biosecurity practices that impact the likelihood of exposure to an EAD, such as the use of appropriate animal movement documentation (75.4%) and isolation of incoming stock (64.9%). However, adoption of other practices relating to feral animal control and biosecurity protocols for visitors were limited. Respondents reported a high uptake of Response Capacity practices, including identifying themselves as responsible for observing (94.6%), reporting unusual signs of disease in their animals (91.0%) and daily/weekly inspection of animals (90.0%). The BN analysis identified six Vulnerability typologies, with three levels of Exposure (high, moderate, low) and two levels of Response Capacity (high, low), as described by producer demographics and practices. The most influential Exposure variables on producer Vulnerability included adoption levels of visitor biosecurity and visitor access protocols. Findings from this study can guide decisions around resource allocation to improve Australia's readiness for EAD incursion and strengthen the country's biosecurity system.

Stakeholder mapping in animal health surveillance: A comparative assessment of networks in intensive dairy cattle and extensive sheep production in Australia

The capacity to rapidly identify and respond to suspicion of animal disease is fundamental to protecting the integrity of the Australian livestock industry. An incursion of a nationally significant endemic, emerging or exotic animal disease could be disruptive and economically damaging for the industry, broader community and national economy. To counter this potential threat, a surveillance system that includes general and targeted activities exists at a jurisdictional and national level. Such a system requires a collaborative effort from all involved to work towards a common goal, reflecting the notion of shared responsibility. As in all systems, the animal health surveillance system can be enhanced or constrained by the relationships of the players involved. This study focusses on two livestock industries, dairy cattle and sheep, exploring the interrelationships between all stakeholders, and their role within the Australian animal health surveillance system. A stakeholder mapping exercise was undertaken, including a depiction of the perceived level of stakeholder interest and influence on producers' animal health surveillance practices and/or the surveillance system. Results from these activities were expanded upon through interviews. The findings reveal complex networks and a system that is, at times, constrained by institutional and individual barriers such as communication between and within stakeholders, and uncertainty about the consequences of reporting a suspected emergency disease. Whilst these challenges have the potential to negatively impact the robustness of the animal disease surveillance system, the study also provides clear evidence of strong and effective relationships amongst many of the key individuals and organisations.

Hendra virus: Epidemiology dynamics in relation to climate change, diagnostic tests and control measures

Hendra virus (HeV) continues to pose a serious public health concern as spillover events occur sporadically. Terminally ill horses can exhibit a range of clinical signs including frothy nasal discharge, ataxia or forebrain signs. Early signs, if detected, can include depression, inappetence, colic or mild respiratory signs. All unvaccinated ill horses in areas where flying foxes exist, may potentially be infected with HeV, posing a significant risk to the veterinary community. Equivac® HeV vaccine has been fully registered in Australia since 2015 (and under an Australian Pesticides and Veterinary Medicines Authority special permit since 2012) for immunization of horses against HeV and is the most effective and direct solution to prevent disease transmission to horses and protect humans. No HeV vaccinated horse has tested positive for HeV infection. There is no registered vaccine to prevent, or therapeutics to treat, HeV infection in humans. Previous equine HeV outbreaks tended to cluster in winter overlapping with the foaling season (August to December), when veterinarians and horse owners have frequent close contact with horses and their bodily fluids, increasing the chance of zoonotic disease transmission. The most southerly case was detected in 2019 in the Upper Hunter region in New South Wales, which is Australia's Thoroughbred horse breeding capital. Future spillover events are predicted to move further south and inland in Queensland and New South Wales, aligning with the moving distribution of the main reservoir hosts. Here we (1) review HeV epidemiology and climate change predicted infection dynamics, (2) present a biosecurity protocol for veterinary clinics and hospitals to adopt, and (3) describe diagnostic tests currently available and those under development. Major knowledge and research gaps have been identified, including evaluation of vaccine efficacy in foals to assess current vaccination protocol recommendations.

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Hendra virus (HeV) continues to pose a serious public health threat to the equine and veterinary industries.

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HeV cases are likely to expand further south and inland due to climate change.

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Strict HeV specific biosecurity protocols should be implemented to protect veterinary staff.

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Research into HeV vaccination protocols in foals is required for evidence-based recommendations.

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Point-of-care and other diagnostic tests for HeV are currently under development.

The goat industry in Australia: Using Bayesian network analysis to understand vulnerability to a foot and mouth disease outbreak

Australia's goat industry is one of the largest goat product exporters in the world, managing both farmed and wild caught animals. To protect and maintain the competitive advantage afforded to the Australian goat industry by the absence of many diseases endemic elsewhere, it is important to identify the vulnerability of producers to livestock disease incursions. This study developed a framework of producer vulnerability built from the beliefs and practices of producers that may impact on their likelihood of exposure and response capacity to an emergency animal disease (EAD), using foot and mouth disease as a model. A cross-sectional questionnaire gathered information on producer/enterprise demographics, animal health management and biosecurity practices, with 107 participating in the study. The biosecurity measures that were most commonly implemented by producers were always using animal movement documentation for purchased stock (74.7 %) and isolating new stock (73.1 %). However, moderate to low uptake of biosecurity protocols related to visitors to the property were reported. Response capacity variables such as checking animals daily (72.0 %) and record keeping (91.7 %) were reported by the majority of respondents, with 40.7 % reporting yearly veterinary inspection of their animals. Using the vulnerability framework, a Bayesian Network model was developed and populated by the survey data, and the relationships between variables were investigated. Six vulnerability profiles were developed, with three levels of exposure (high, moderate, low) and two levels of response capacity (high, low), as described by producer demographics and practices. The most sensitive exposure variables on producer vulnerability included implementation of visitor biosecurity and control of feral animals. Results from this study can inform risk based perspectives and decisions around biosecurity and surveillance resource allocation within the goat industry. The results also highlight opportunities for improving Australia's preparedness for a future EAD incursion by considering producer behaviour and beliefs by applying a vulnerability framework.

Equine influenza vaccination in the UK: Current practices may leave horses with suboptimal immunity

BACKGROUND

Vaccination is integral to preventive healthcare. Despite numerous guidelines on equine vaccination, evidence of current vaccination practices is lacking.

OBJECTIVES

To describe current vaccination practices advised by vets treating horses in the United Kingdom (UK) and compare practices with manufacturer datasheets and current guidelines.

STUDY DESIGN

Cross-sectional survey.

METHODS

An online questionnaire was distributed using email addresses acquired through professional registration listings and social media, targeting vets who treat horses in the UK. The questionnaire collected demographic data and information regarding vaccination practices and vaccine hesitancy. Descriptive statistical analysis was performed.

RESULTS

Questionnaires were completed by 304 UK vets working with horses used for leisure (97.4%, n = 296/304), competition (86.2%, n = 262/304), stud-work (47.7%, n = 145/304) and racing (40.5%, n = 123/304). Variation was identified in vaccine protocols for competition and noncompetition horses. Fifty-seven per cent (n = 170/298) of respondents reported variation in advised 'booster' frequency; most commonly (n = 118) advising a 6-monthly vaccination in competition horses and annual vaccination in noncompetition horses. Most common vaccination guidelines volunteered were British Horseracing Authority (68.8%, n = 172/250) and Federation Equestre Internationale (66.4%, n = 166/250). Most vaccination practices were not consistent with datasheet guidance. Only 7.7% (n = 23/300) of respondents complied with datasheet timeframes between the second and third vaccination. Adverse events following vaccination in the previous year were encountered by 66% (n = 199/304) of respondents, representing 2760 adverse events; but only 526 (19.1%) cases were reported to the Veterinary Medicines Directorate. Most common reactions were transient, including stiffness (931), localised swelling (835), lethargy (559) and pyrexia (355). 86.4% respondents reported vaccine hesitancy from horse owners, most commonly due to perception of over-vaccination, cost and concern regarding adverse events.

MAIN LIMITATIONS

Potential selection, respondent and recall bias. The recent Equine Influenza (EI) and Equine Herpes Virus (EHV) outbreaks in the UK may have altered responses.

CONCLUSIONS

Current equine vaccination practices, although complying with competition rules, are mostly noncompliant with datasheet guidelines, potentially risking suboptimal immunity.

Socially vs. Privately Optimal Control of Livestock Diseases: A Case for Integration of Epidemiology and Economics

This paper aims to illustrate the interdependencies between key epidemiological and economic factors that influence the control of many livestock infectious diseases. The factors considered here are (i) farmer heterogeneity (i.e., differences in how farmers respond to a perceived disease risk), (ii) off-farm effects of farmers' actions to control a disease (i.e., costs and benefits borne by agents that are external to the farm), and (iii) misalignment between privately and socially optimal control efforts (i.e., privately optimal behavior not conducive to a socially optimal outcome). Endemic chronic diseases cause a wide range of adverse social and economic impacts, particularly in low-income countries. The actions taken by farmers to control livestock diseases minimize some of these impacts, and heterogeneity in those actions leads to variation in prevalence at the farm level. While some farmers respond to perceived disease risks, others free-ride on the actions of these individuals, thereby compromising the potential benefits of collective, coordinated behavior. When evaluating a plausible range of disease cost to price of control ratios and assuming that farmers choose their privately optimal control effort, we demonstrate that achievement of a socially optimal disease control target is unlikely, occurring in <25% of all price-cost combinations. To achieve a socially optimal disease control outcome (reliant on farmers' voluntary actions), control policies must consider farmer heterogeneity, off-farm effects, and the predicted uptake of control measures under the assumption of optimized behavior.

Hendra in the Hunter Valley

In June 2019 the first equine case of Hendra virus in the Hunter Valley, New South Wales, Australia was detected. An urgent human and animal health response took place, involving biosecurity measures, contact tracing, promotion of equine vaccinations and investigation of flying fox activity in the area.

No human or additional animal cases occurred. Equine vaccination uptake increased by over 30-fold in the surrounding region in the three months following the case. Black flying fox and grey-headed flying fox species were detected in the Valley. The incident prompted review of Hendra virus resources at local and national levels.

This event near the “horse capital of Australia”, is the southernmost known equine Hendra case. Management of the event was facilitated by interagency collaboration involving human and animal health experts. Ongoing One Health partnerships are essential for successful responses to future zoonotic events.

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In June 2019 the southernmost known equine case of Hendra virus was detected in the Hunter Valley, Australia.

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This signified an increase in potential equine and human populations at risk of infection.

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Interagency collaboration between animal and human health experts is essential in managing Hendra virus spillover events.

Citizens' juries give verdict on whether private practice veterinarians should attend unvaccinated Hendra virus suspect horses

BACKGROUND

Hendra virus (HeV) is endemic in Australian flying foxes, posing a threat to equine and human health. Equine vaccination remains the most effective risk mitigation strategy. Many horses remain unvaccinated - even in higher-risk regions. Debate surrounding the vaccine's use is characterised by conflicting perspectives, misunderstanding and mistrust. Private veterinary practitioners are critical to early identification of public health risk through recognition, sampling and management of suspect-equine-HeV-cases. However, managing such cases can be burdensome, with some veterinarians opting not to attend unvaccinated horses or to abandon equine practice because of risk posed by HeV disease and liability.

OBJECTIVE

Ascertain the perspectives of informed citizens on what obligations (if any) private veterinarians have to attend unvaccinated horses with HeV or HeV-like disease.

METHODS

Three citizens' juries were tasked with considering approaches to managing HeV risk in Australia, including (reported here) roles and obligations of private veterinarians in responding to HeV-suspect-cases.

RESULTS

Jurors acknowledged that HeV management posed an important challenge for private veterinarians. A clear majority (27 of 31 jurors) voted that veterinarians should not be obliged to attend unvaccinated horses. All recognised that greater support for veterinarians should be a priority.

CONCLUSIONS

When informed of HeV risks and strategies for control and management, citizens appreciated the need to support veterinarians performing this critical 'One Health' role for public benefit. The current governance framework within which zoonotic disease recognition and response operates limits the contingency and scope for increasing support and efficacy of these important veterinary public health practices.

Equine influenza vaccination as reported by horse owners and factors influencing their decision to vaccinate or not

BACKGROUND

Equine influenza virus is a highly contagious respiratory pathogen that causes pyrexia, anorexia, lethargy and coughing in immunologically naïve horses. Vaccines against equine influenza are available and vaccination is mandatory for horses that participate in affiliated competitions, but this group forms a small proportion of the total horse population. The aims of this study were to: i) identify the equine influenza vaccination rate as reported in 2016 by horse owners in the United Kingdom (UK); ii) examine the demographics of owners and horses which were associated with significantly lower influenza vaccination rates and iii) explore factors that influence horse owners' decisions around influenza vaccine uptake.

RESULTS

Responses from 4837 UK horse owners who were responsible for 10,501 horses were analysed. An overall equine influenza vaccination rate of 80% (8385/10501) was reported. Several owner demographic characteristics were associated with significantly lower (p<0.05) reported equine influenza vaccination rates including: some geographical locations, increasing horse owner age, annual household income of less that £15,000 and owning more than one horse. Horse-related features which were associated with significantly lower reported equine influenza vaccination rates included age ranges of <4 years and > 20 years, use as a companion or breeding animal or leaving their home premises either never or at most once a year. The most common reasons cited for failing to vaccinate horses was no competition activity, lack of exposure to influenza and expense of vaccines. In contrast, the most common underlying reasons given by horse owners who vaccinated their horse were protection of the individual horse against disease, veterinary advice and to protect the national herd. Owners of vaccinated horses had less previous experience of an influenza outbreak or adverse reaction to vaccination compared with owners of unvaccinated horses.

CONCLUSIONS

This study documented a high rate of equine influenza vaccination as reported by owners in a substantial number of horses in the UK, but this does not reflect the level of protection. Sub-populations of horses which were less likely to be vaccinated and the factors that influence each owner's decision around vaccination of their horses against equine influenza were identified, but may alter following the 2019 European influenza outbreak. This information may nevertheless help veterinary surgeons identify "at-risk" patients and communicate more personalised advice to their horse-owning clients. It may also influence educational campaigns about equine influenza directed to horse owners, which aim to improve uptake of vaccination against this pathogen.

Obstacles to vaccination of animals and prospective solutions

On the 17th of October 2019, a workshop was held at Wageningen Bioveterinary Research in Lelystad, the Netherlands, to discuss the obstacles to vaccination in the veterinary field. Participants from academia, OIE, FAO, EC, EMA, USDA, national regulatory and veterinary health authorities, and the animal health industry discussed how availability and access to animal vaccines can be improved not just in the EU and US but also in Low to Middle Income Countries (LMIC) across the world and agreed that this requires innovations in both the scientific and the regulatory field. The workshop called for engaging all stakeholders to improve regulatory acceptance of novel vaccine technologies and encourage their registration. There is a need for better mutual understanding between academia, industry and regulators, and more openness to discuss framework, requirements, and product authorisations, and to converge the regulatory rules between regions. The next leap forward could be a broader application of novel technologies using RNA- or DNA-based vaccine platforms, where the "backbone" is maintained, while the gene of interest coding for an immunogenic protein can be exchanged in a standardised manner. This approach enables rapid response in outbreak situations and should lower the risk and cost of vaccine development.

Time of year, age class and body condition predict Hendra virus infection in Australian black flying foxes (Pteropus alecto)

Hendra virus (HeV) continues to cause fatal infection in horses and threaten infection in close-contact humans in eastern Australia. Species of Pteropus bats (flying-foxes) are the natural reservoir of the virus. We caught and sampled flying-foxes from a multispecies roost in southeast Queensland, Australia on eight occasions between June 2013 and June 2014. The effects of sample date, species, sex, age class, body condition score (BCS), pregnancy and lactation on HeV antibody prevalence, log-transformed median fluorescent intensity (lnMFI) values and HeV RNA status were assessed using unbalanced generalised linear models. A total of 1968 flying-foxes were sampled, comprising 1012 Pteropus alecto, 742 P. poliocephalus and 214 P. scapulatus. Sample date, species and age class were each statistically associated with HeV RNA status, antibody status and lnMFI values; BCS was statistically associated with HeV RNA status and antibody status. The findings support immunologically naïve sub-adult P. alecto playing an important role in maintaining HeV infection at a population level. The biological significance of the association between BCS and HeV RNA status, and BCS and HeV antibody status, is less clear and warrants further investigation. Contrary to previous studies, we found no direct association between HeV infection and pregnancy or lactation. The findings in P. poliocephalus suggest that HeV exposure in this species may not result in systemic infection and virus excretion, or alternatively, may reflect assay cross-reactivity with another (unidentified) henipavirus.

Understanding the vulnerability of beef producers in Australia to an FMD outbreak using a Bayesian Network predictive model

Effective and adaptable biosecurity and surveillance systems are crucial for maintaining and increasing Australia's competitive advantages in international markets, and for the production of high quality, safe animal products. These systems are continuously strengthened by ongoing government and industry investment. However, a better understanding of evolving disease risks and the country's capacity to respond to these risks is needed. This study developed a vulnerability framework based on characteristics and behaviours of livestock producers that impact exposure and response capacity to an emergency animal disease (EAD) outbreak among beef producers in Australia, with a focus on foot and mouth disease (FMD). This framework articulated producer vulnerability typologies to better inform surveillance resource allocation and future research direction. A cross-sectional study of beef producers in Australia was conducted to gather information on producers' demographics, husbandry characteristics, biosecurity and animal health management practices and beliefs, including those specific to FMD risk and response capacity. A Bayesian Network (BN) model was developed from the vulnerability framework, to investigate the complex interrelationships between variables and identify producer typologies. A total of 375 usable responses were obtained from the cross-sectional study. Regarding EAD exposure, producers implemented appropriate biosecurity practices for incoming stock, such as isolation (72.0 %), inspection for disease (88.7 %) and the use of vendor declarations (78.5 %); however, other biosecurity practices were limited, such as restriction of visitor access, visitor biosecurity requirements or feral animal control. In relation to response capacity, a moderate uptake of practices was observed. Whilst daily or weekly visual inspection of animals was reported by most producers (90.1 %), physical inspection was less frequent. Most producers would call a private veterinarian in response to unusual signs of disease in their cattle; however, over 40 % of producers did not cite calling a government veterinarian as a priority action. Most producers believe an FMD outbreak would have extremely serious consequences; however, their level of concern was moderate and their confidence in identifying FMD symptoms was low. The BN analysis identified six vulnerability typologies, with three levels of exposure (high, moderate, low) and two levels of response capacity (high, low), as described by producer demographics and practices. The model identified property size, number of cattle and exposure variables as the most influential to the overall producer vulnerability. Results from this study can inform how to best use current biosecurity and surveillance resources and identify where opportunities exist for improving Australia's preparedness for future EAD incursions.

Preliminary insight into horse owners' perceptions of, and attitudes towards, exotic diseases in the United Kingdom

Background

The potential for an exotic disease incursion is a significant concern for the United Kingdom (UK) equine industry. Horse owners’ perceptions of, and attitudes towards, exotic diseases can influence decisions to adopt disease preparedness strategies. The objectives of this study were to describe horse owners’ 1) perceptions of the term ‘exotic disease’, and 2) attitudes towards their risk of being affected by an exotic disease. In order to address these objectives, qualitative content analysis was undertaken on data collected using two open-ended survey questions.

Results

Horse owners (n = 423) perceived exotic diseases as 1) belonging somewhere else, and 2) a dangerous threat to their horse(s). The term ‘exotic’ was associated with being foreign, non-native, and out-of-place in the UK. Attitudes towards exotic disease risk were summarised into four categories: 1) responsible horse owners prevent disease, 2) horse owners need support to stop disease spread, 3) risk depends on proximity to the ‘risky’ horse, and 4) some risk is inevitable. A ‘responsible’ owner was aware of health hazards and took actions to protect their horse from disease. Reliance on others, including stakeholders, to uphold disease prevention in the community led to feeling vulnerable to disease threats. When evaluating risk, horse owners considered which horses were the ‘riskiest’ to their horse’s health (horses that travelled, participated in competitions, or were simply unfamiliar) and avoided situations where they could interact. Despite undertaking disease prevention measures, the perceived uncontrollable nature of exotic diseases led some owners to feel an incursion was inevitable.

Conclusions

Without accounting for horse owners’ perceptions of, and attitudes towards, exotic diseases, recommendations to increase preparedness may be ineffective. Improved communication among stakeholders in the industry may assist in clarifying expectations for exotic disease-specific prevention measures. A collaborative approach among horse owners and stakeholders is recommended to improve disease preparedness within the industry.

Ecological interventions to prevent and manage zoonotic pathogen spillover

Spillover of a pathogen from a wildlife reservoir into a human or livestock host requires the pathogen to overcome a hierarchical series of barriers. Interventions aimed at one or more of these barriers may be able to prevent the occurrence of spillover. Here, we demonstrate how interventions that target the ecological context in which spillover occurs (i.e. ecological interventions) can complement conventional approaches like vaccination, treatment, disinfection and chemical control. Accelerating spillover owing to environmental change requires effective, affordable, durable and scalable solutions that fully harness the complex processes involved in cross-species pathogen spillover.

This article is part of the theme issue ‘Dynamic and integrative approaches to understanding pathogen spillover’.

A cross-sectional study of horse owners' awareness and perceived risk of exotic diseases in the United Kingdom

The international nature of the equine industry provides opportunities for the spread of infectious diseases between countries. While incursions of exotic diseases into the United Kingdom (UK) equine population have been rare, the potential socioeconomic and welfare impacts are a significant concern. However, little is known about leisure horse owners' ability or willingness to prepare for an exotic disease incursion. The objectives of this study were to describe UK leisure horse owners' awareness and perceptions of exotic diseases, and to identify clusters of horse owners characterised by their awareness and perceived risk of exotic diseases. A cross-sectional study of leisure horse owners in the UK was conducted between April and July 2018. Participants (n = 403) completed an online questionnaire with questions pertaining to demographics, experiences with endemic diseases, and awareness and perceptions of exotic diseases. Hierarchical cluster analysis was used to identify groups of participants that were similar in regard to their awareness and perceived risk of exotic diseases. Participants identified a median of 3 (IQR 2-4) exotic diseases, with the most recognised exotic diseases being African horse sickness and West Nile virus. The most frequently mentioned clinical signs that participants thought were associated with exotic diseases included high temperature (57.2%), discharge (46.5%), and lack of energy (41.2%). Hierarchical cluster analysis identified three clusters of participants: 1) those who were aware of exotic diseases and perceived a high amount of risk (n = 78); 2) those who were aware of exotic diseases but perceived a low amount of risk (n = 111); and 3) those who were less aware of exotic diseases and perceived a low amount of risk (n = 214). Efforts to communicate the relevance and consequences of exotic diseases to horse owners should consider the potential difference in receptiveness among horse owners in each cluster. Further investigations are required to determine the implications of horse owners' perceived risk on exotic disease preparedness.

Henipaviruses at the Interface Between Bats, Livestock and Human Population in Africa

Nipah virus (NiV) and Hendra virus (HeV) are closely related members within the genus Henipavirus, family Paramyxoviridae, for which fruit bats serve as the reservoir. The initial emergence of NiV infections in pigs and humans in Malaysia, and HeV infections in horses and humans in Australia, posed severe impacts on human and animal health, and continues threatening lives of humans and livestock within Southeast Asia and Australia. Recently, henipavirus-specific antibodies have also been detected in fruit bats in a number of sub-Saharan African countries and in Brazil, thereby considerably increasing the known geographic distribution of henipaviruses. Africa is progressively being recognized as a new high prevalence zone for henipaviruses, as deduced from serological and molecular evidence of past infections in Madagascar, Ghana, Republic of Congo, Gulf of Guinea, Zambia, Tanzania, Cameroon, and Nigeria lately. Serological data suggest henipavirus spillover from bats to livestock and human populations in Africa without reported clinical disease in any of these species. All virus isolation attempts have been abortive, highlighting the need for further investigations. The genome of the Ghanaian bat henipavirus designated Ghana virus (GhV), which was detected in a pteropid Eidolon helvum bat, is the only African henipavirus that has been completely sequenced limiting our current knowledge on the genetic diversity and pathogenesis of African henipaviruses. In this review, we summarize the available data on the circulation of henipaviruses in Africa, discuss potential sources for virus spillover, and highlight existing research gaps.

Managing the risk of Hendra virus spillover in Australia using ecological approaches: A report on three community juries

BACKGROUND

Hendra virus (HeV) infection is endemic in Australian flying-fox populations. Habitat loss has increased the peri-urban presence of flying-foxes, increasing the risk of contact and therefore viral 'spillovers' into horse and human populations. An equine vaccine is available and horse-husbandry practices that minimize HeV exposure are encouraged, but their adoption is suboptimal. Ecological approaches-such as habitat creation and conservation-could complement vaccination and behavioural strategies by reducing spillover risks, but these are controversial.

METHODS

We convened three community juries (two regional; one metropolitan) to elicit the views of well-informed citizens on the acceptability of adding ecological approaches to current interventions for HeV risk. Thirty-one participants of diverse backgrounds, mixed genders and ages were recruited using random-digit-dialling. Each jury was presented with balanced factual evidence, given time to ask questions of expert presenters and, after deliberation, come to well-reasoned conclusions.

RESULTS

All juries voted unanimously that ecological strategies should be included in HeV risk management strategies but concluded that current interventions-including vaccination and changing horse-husbandry practices-must remain the priority. The key reasons given for adopting ecological approaches were: (i) they address underlying drivers of disease emergence, (ii) the potential to prevent spillover of other bat-borne pathogens, and (iii) there would be broader community benefits. Juries differed regarding the best mechanism to create/conserve flying-fox habitat: participants in regional centres favoured direct government action, whereas the metropolitan jury preferred to place the burden on landholders.

CONCLUSIONS

Informed citizens acknowledge the value of addressing the drivers of bat-borne infectious risks but differ substantially as to the best implementation strategies. Ecological approaches to securing bat habitat could find broad social support in Australia, but disagreement about how best to achieve them indicates the need for negotiation with affected communities to co-develop fair, effective and locally appropriate policies.

Viral glycoproteomes: technologies for characterization and outlook for vaccine design

It has long been known that surface proteins of most enveloped viruses are covered with glycans. It has furthermore been demonstrated that glycosylation is essential for propagation and immune evasion for many viruses. The recent development of high-resolution mass spectrometry techniques has enabled identification not only of the precise structures but also the positions of such post-translational modifications on viruses, revealing substantial differences in extent of glycosylation and glycan maturation for different classes of viruses. In-depth characterization of glycosylation and other post-translational modifications of viral envelope glycoproteins is essential for rational design of vaccines and antivirals. In this Review, we provide an overview of techniques used to address viral glycosylation and summarize information on glycosylation of enveloped viruses representing ongoing public health challenges. Furthermore, we discuss how knowledge on glycosylation can be translated to means to prevent and combat viral infections.

Investigation of the effect of Equivac® HeV Hendra virus vaccination on Thoroughbred racing performance

OBJECTIVE

To evaluate the effect of Equivac® HeV Hendra virus vaccine on Thoroughbred racing performance.

DESIGN

Retrospective pre-post intervention study.

METHODS

Thoroughbreds with at least one start at one of six major south-eastern Queensland race tracks between 1 July 2012 and 31 December 2016 and with starts in the 3-month periods before and after Hendra virus vaccinations were identified. Piecewise linear mixed models compared the trends in 'Timeform rating' and 'margin to winner' before and after initial Hendra virus vaccination. Generalised linear mixed models similarly compared the odds of 'winning', 'placing' (1st-3rd) and 'winning any prize money'. Timeform rating trends were also compared before and after the second and subsequent vaccinations.

RESULTS

Analysis of data from 4208 race starts by 755 horses revealed no significant difference in performance in the 3 months before versus 3 months after initial Hendra vaccination for Timeform rating (P = 0.32), 'Margin to winner' (P = 0.45), prize money won (P = 0.25), wins (P = 0.64) or placings (P = 0.77). Further analysis for Timeform rating for 7844 race starts by 928 horses failed to identify any significant change in Timeform rating trends before versus after the second and subsequent vaccinations (P = 0.16) or any evidence of a cumulative effect for the number of vaccines received (P = 0.22).

CONCLUSION

No evidence of an effect of Hendra virus vaccination on racing performance was found. The findings allow owners, trainers, industry regulators and animal health authorities to make informed decisions about vaccination.