Australian Centre for Disease Preparedness (ACDP), Commonwealth Scientific and Industrial Research Organisation (CSIRO), East Geelong, VIC 3219, Australia
Dr. Kim Halpin
Australian Centre for Disease Preparedness (ACDP), Commonwealth Scientific and Industrial Research Organisation (CSIRO), East Geelong, VIC 3219, Australia
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.
In this paper, the authors: (a) list methods used to diagnose zoonotic diseases in humans and animals; (b) identify between-species differences in diagnostic approaches, providing commentary on the benefits that might arise from simultaneous interpretation of data from human and animal health surveillance systems; and (c) reiterate the importance of using species-specific, validated diagnostic tests for surveillance and disease outbreak investigations. Emerging and endemic zoonotic diseases are likely to provide a continued threat to global health in the short- to medium-term future. A good deal of knowledge about the drivers of infectious disease emergence has been developed based on numerous examples from the recent past. Sharing of diagnostic resources across human and animal health sectors, sharing of human and animal health surveillance data, development of skills in the interpretation of that data and awareness of issues related to the validation and interpretation of diagnostic test data are necessary prerequisites for an effective endemic disease surveillance system. A good understanding of the epidemiological patterns of endemic disease will allow human and animal health professionals be able to more quickly detect the presence of emerging disease threats. Los autores proceden aquí a: a) relacionar los métodos empleados para diagnosticar enfermedades zoonóticas en personas y animales; b) señalar las diferencias que existen entre los distintos planteamientos de diagnóstico según la especie de que se trate, comentando asimismo las ventajas que podrían derivarse de la interpretación simultánea de los datos de los sistemas de vigilancia sanitaria y de los de vigilancia zoosanitaria; y c) reiterar la importancia que reviste el uso de pruebas de diagnóstico no solo validadas, sino también adaptadas específicamente a cada especie, para las labores de vigilancia y estudio de brotes. Lo más probable es que a corto y medio plazo las enfermedades zoonóticas, ya sean emergentes o endémicas, sigan constituyendo una amenaza para la salud mundial. Gracias a numerosos ejemplos del pasado reciente se ha ido constituyendo un buen conocimiento de los factores que propician la aparición de enfermedades infecciosas. Para disponer de un eficaz sistema de vigilancia de enfermedades endémicas hay una serie de requisitos previos indispensables: utilización compartida de los recursos de diagnóstico entre los sectores de la salud humana y la sanidad animal; intercambio de los datos de vigilancia sanitaria y de vigilancia zoosanitaria; adquisición de competencias para interpretar esos datos; y buen conocimiento de las cuestiones ligadas a la validación de pruebas de diagnóstico y a la interpretación de los datos que arrojan. Si los profesionales de la salud humana y la sanidad animal conocen debidamente los patrones epidemiológicos de las enfermedades endémicas, estarán en condiciones de detectar con más celeridad la presencia de enfermedades emergentes que constituyan una amenaza. Après avoir répertorié les méthodes utilisées pour diagnostiquer les maladies zoonotiques chez l’homme comme chez les animaux, les auteurs définissent les différentes approches diagnostiques suivant les espèces considérées et commentent les avantages qui pourraient découler d’une interprétation simultanée des données par les systèmes de surveillance en santé animale et en santé publique ; il réitèrent ensuite l’importance de recourir à des tests diagnostiques validés et spécifiques de l’espèce considérée dans le cadre de la surveillance et des enquêtes suite à l’apparition d’un foyer. Les maladies zoonotiques émergentes et endémiques représentent potentiellement une menace continue pour la santé mondiale à court et à moyen terme. Les facteurs favorisant l’émergence des maladies infectieuses sont désormais beaucoup mieux connus grâce aux enseignements tirés de nombreux exemples récents. Le partage des ressources diagnostiques entre les secteurs de la santé humaine et animale, les échanges des données de la surveillance sanitaire réunies par les deux secteurs, le renforcement des compétences en matière d’interprétation des données et la sensibilisation aux problématiques de la validation et de l’interprétation des données générées par les tests de diagnostic sont des conditions préalables à la mise en place d’un système efficace de surveillance des maladies endémiques. Une bonne compréhension des profils épidémiologiques des maladies endémiques permettra aux professionnels de la santé humaine et animale de détecter plus rapidement la présence de menaces émergentes.
Hendra virus (HeV) emerged in Australia in 1994, causing a devastating outbreak among horses in Brisbane with spread to humans, resulting in one death. This nonsegmented, negative-stranded RNA virus belongs to the family Paramyxoviridae and represents the first zoonotic paramyxovirus isolated from bats. Flying foxes (genus Pteropus ) serve as the natural reservoir, with all four mainland Australian species carrying antibodies with no apparent disease. HeV initiates infection by binding ephrin-B2 receptors on vascular endothelial cells, driving characteristic pathology involving vasculitis, thrombosis, and neurological complications. Horses are amplifying hosts, shedding virus abundantly in respiratory secretions and posing transmission risks to humans during invasive procedures. To date, seven confirmed human infections have been documented, with a 57% fatality rate, presenting as severe respiratory disease or progressive encephalitis. Two genetic variants are now recognized: the original HeV genotype 1 and the emerging HeV genotype 2, identified in limited equine cases. Recent surveillance of bat roosts revealed substantial viral diversity, with peak shedding occurring during winter—coinciding with equine spillover peaks. Prevention integrates multiple strategies: the licensed equine vaccine Equivac which provides One Health protection for both horses and human contacts; biosecurity measures including proper PPE; and habitat restoration to reduce nutritional stress in bat populations. Emerging therapeutics include monoclonal antibodies, with m102.4 showing cross-protective activity against both HeV and the closely related Nipah virus. No licensed human vaccines currently exist, though candidates are in development. Future prevention strategies increasingly recognize the importance of Indigenous-led conservation approaches alongside biomedical interventions. This review will focus on the history of HeV, virus replication and diversity, epidemiology, clinical manifestations, diagnosis, treatment, prevention, as well as ecological and interdisciplinary countermeasures.