Emerging infectious disease prevention: Veterinary action required.

Emerging and re-emerging infectious disease outbreaks have increased significantly over the past century, largely due to human actions, leading to distress, death and severe socio-economic implications. Coordinated actions by multiple sectors and disciplines are required to address these drivers. The challenge for the veterinary profession is to identify and prioritise the actions to which it can and should contribute. This review explores: the extent to which veterinary oaths promote attention to ecological sustainability; challenges faced during One Health implementation across diverse settings and possible solutions; and opportunities for veterinarians to assist with pandemic prevention by working to stop viral spillover at source. It aims to stimulate a discussion within the veterinary profession regarding how our current approaches: prevent or promote emerging infectious diseases and re-emerging infectious diseases; provide opportunities to improve our preventive contributions going forward; and can yield significant cobenefits.

Planetary boundaries and Veterinary Services.

National Veterinary Services (NVS) play a crucial role in animal health, production and welfare. They are also intimately involved with safeguarding global health security and the health of the planet. Climate change is just one of the nine planetary boundaries (PBs), i.e. Earth system processes, that can be used to monitor the vital signs of our living planet. In this paper, the authors identify the positive and negative impacts of humaninduced management of aquatic and terrestrial animals in relation to these PBs. In the context of NVS, the authors provide an overview of the real and potential impacts of NVS policies on Earth systems and offer suggestions as to how new sustainability paradigms may assist with reviewing and revising NVS mandates and facilitating stakeholder engagement. Opportunities are proposed for the World Organisation for Animal Health to contribute to the global debate on the role of aquatic and terrestrial animal agriculture and wildlife in sustainable development. In addition, the paper suggests that a wider debate is required in relation to recent significant increases in domestic animal populations and PBs. Intersectoral and interdisciplinary collaboration are required to achieve the transformation of the framework in which NVS operate. While such transformations cannot be driven by the veterinary profession alone, veterinarians have proven very effective operators in the One Health arena. By building on these intersectoral linkages, it will be possible for our profession and NVS to actively contribute to the crucial discussions and transformations required to pull Earth system metrics back within safe boundaries.

Les Services vétérinaires nationaux jouent un rôle crucial dans les domaines de la santé animale, de la production animale et du bien-être des animaux. Mais ils sont aussi fortement engagés dans la protection de la sécurité sanitaire mondiale et de la santé de la planète. Le changement climatique est l'une des neuf frontières planétaires existantes, c'est-à-dire les neuf processus du système terrestre qui peuvent nous aider à surveiller les signes vitaux de notre planète vivante. Les auteurs font le point sur les impacts positifs et négatifs de la gestion par l'homme des animaux aquatiques et terrestres dans la perspective de ces frontières planétaires. S'agissant des Services vétérinaires nationaux, les auteurs donnent un aperçu de l'impact réel des politiques des Services vétérinaires sur les systèmes terrestres ainsi que des possibilités en la matière et font quelques propositions pour que les mandats de ces Services soient repensés et modifiés et la participation des parties prenantes facilitée à la lumière des nouveaux paradigmes de durabilité. Ils évoquent plusieurs occasions au cours desquelles l'Organisation mondiale de la santé animale (OIE) pourrait contribuer aux discussions à l'échelle mondiale sur le rôle des animaux terrestres et aquatiques, tant d'élevage que sauvages, dans le développement durable. En outre, les auteurs estiment qu'un débat plus général est nécessaire concernant l'augmentation récente et significative des populations d'animaux domestiques et les frontières planétaires. Une collaboration intersectorielle et interdisciplinaire sera nécessaire pour transformer le cadre dans lequel interviennent les Services vétérinaires nationaux. Certes, une transformation de cette nature ne peut être menée par la profession vétérinaire seule, mais les vétérinaires ont déjà fait preuve de l'efficacité de leurs capacités opérationnelles dans l'arène Une seule santé. En s'appuyant sur ces liens intersectoriels, la profession vétérinaire et les Services vétérinaires nationaux seront à même de contribuer activement aux discussions cruciales ainsi qu'aux transformations indispensables pour ramener les variables mesurables de la Terre à l'intérieur de frontières sûres.

La función de los Servicios Veterinarios nacionales, además de ser crucial para la sanidad, la producción y el bienestar animales, guarda estrecha relación con la salvaguarda de la seguridad sanitaria mundial y la salud del planeta. El cambio climático es solo uno de los nueve límites planetarios, esto es, procesos del sistema terrestre, que cabe utilizar para seguir de cerca los signos vitales del ser vivo que es nuestro planeta. Los autores exponen los efectos tanto positivos como negativos que en relación con estos límites planetarios trae consigo la gestión antrópica de animales acuáticos y terrestres. Por lo que respecta a los Servicios Veterinarios nacionales, los autores presentan a grandes líneas las repercusiones que las políticas de estos Servicios Veterinarios tienen o pueden tener en los sistemas terrestres y proponen fórmulas para que los nuevos paradigmas de la sostenibilidad ayuden a examinar y revisar el mandato de los Servicios Veterinarios nacionales y a facilitar la participación de los demás interlocutores. También señalan las oportunidades que tiene ante sí la Organización Mundial de Sanidad Animal para contribuir a las deliberaciones mundiales sobre la función de la producción de animales acuáticos y terrestres y de la gestión de la fauna silvestre con vistas al desarrollo sostenible. Los autores, además, consideran necesario un debate más amplio en relación con el reciente y considerable crecimiento de las poblaciones de animales domésticos y los límites planetarios. Para lograr una transformación de las coordenadas en las que operan los Servicios Veterinarios de los países se requiere una colaboración tanto intersectorial como interdisciplinar. Aunque estos cambios no pueden venir únicamente de la mano de la profesión veterinaria, la labor de los veterinarios en el ruedo de Una sola salud ha demostrado que son agentes muy eficaces. Profundizando en estos vínculos intersectoriales, será posible que nuestra profesión y los Servicios Veterinarios nacionales contribuyan activamente a las cruciales deliberaciones y transformaciones que se necesitan para que el valor de los parámetros del sistema terrestre vuelva a situarse dentro de los márgenes de seguridad.

One Health, veterinarians and the nexus between disease and food security.

Achieving ecologically sustainable food systems for people and animals is one of the greatest challenges facing our world today. Four interdisciplinary approaches that promote a holistic, systems approach to disease prevention and food security are introduced. Current domestic and international initiatives that link disease prevention with food and nutrition security are presented, with an emphasis on animal-source food and examples from Australia, Tanzania and Timor-Leste. Veterinarians are uniquely placed to use their training in comparative physiology in support of the production of sustainable, nutritious, ethical and safe food delivered with minimal waste to promote human, animal and environmental health.

Challenges and constraints to vaccination in developing countries.

The challenges and constraints to vaccinating poultry in areas where adequate infrastructure and human resources are lacking are addressed in both a technical and a socioeconomic framework. The key issues discussed are: (1) selection of an appropriate vaccine and vaccination technique, including the advantages and disadvantages of a combined vaccine against highly pathogenic avian influenza (HPAI) and Newcastle disease and addressing the differences between endemic disease and emergency disease control; (2) vaccine conservation and distribution; (3) evaluation of the flocks to be vaccinated in terms of their disease status, immunocompetence and production systems; (4) design of effective information, education and communication materials and methods with and for veterinary and extension staff as well as commercial and smallholder producers and community vaccinators in rural areas; (5) evaluation and monitoring systems for technical and socioeconomic factors that affect vaccination; (6) support and coordination of and by relevant public and private agencies; (7) the role of simultaneous implementation of other control activities in addition to vaccination; (8) the importance of assessing the costs and cost-effectiveness of various approaches to the control of HPAI, including the prevention of other endemic killer diseases and options for cost-sharing; (9) evaluation of the incentives for poultry-holders, vaccinators and vaccine producers to contribute to and participate in effective vaccination campaigns; and (10) policy development and the organizational framework for short- and long-term implementation and communication to decision-makers.

Lymphocyte subpopulations in lymph and blood draining from the uterus and ovary in sheep.

Lymphocyte subsets in utero-ovarian peripheral lymph and uterine and jugular venous blood were analysed with the aid of monoclonal antibodies, polyclonal antisera and flow microfluorometry. The proportion of various lymphocyte subpopulations, as determined by monoclonal antibodies (mAbs) and polyclonal antisera, was found to vary between utero-ovarian peripheral lymph and jugular and uterine venous blood. T cell levels were higher in utero-ovarian peripheral lymph (approx. 80% CD5+, 50% CD4+ and 23% CD8+) than peripheral blood (approx. 55% CD5+, 18% CD4+ and 12% CD8+). Conversely, in lymph, 10% of lymphocytes were B cells compared to 30% in blood. There were 20-30% MHC II+ cells in utero-ovarian peripheral lymph and 40-50% in blood. The level of CD45R+ cells in utero-ovarian peripheral lymph was low (2%) compared to peripheral blood (approx. 55% in pregnant and 25% in non-pregnant ewes). The proportion of lymphocyte subpopulations in lymph was similar for pregnant and non-pregnant ewes. However, some differences in levels in peripheral blood were evident between uterine and jugular venous blood and pregnant and non-pregnant ewes. CD4+ cells were higher in the uterine vein (14%) than in the jugular vein (11%) of pregnant ewes. The uterine and jugular veins in pregnant ewes contained approx. 50% MHC II+ cells compared to 30% in non-pregnant ewes. Likewise, the proportion of CD45R+ cells was higher in uterine and jugular venous blood of pregnant ewes (approx. 58%) compared to non-pregnant ewes (around 25%).

Cellular composition of utero-ovarian lymph during the exogenous gonadotrophin-stimulated oestrous cycle in sheep.

Utero-ovarian peripheral lymph was collected for extended periods from sheep that had received exogenous gonadotrophins. High lymph flow rates and progesterone outputs, over 13 mL h-1 and 65 nmol h-1 respectively, were observed during the subsequent oestrous cycles. A positive correlation was found between the maximum lymph flow rate and the number of corpora lutea in the draining ovary. At periods approximating the beginning and end of the luteal phase of the oestrous cycle there were increases in the output of red blood cells and, towards the end of the luteal phase, eosinophils constituted over 10% of the white blood cells in the lymph. Lymph provides a dynamic record of the changing internal environment of the ovary and as such may yield useful information on intraovarian control mechanisms in sheep.

Mg2+-dependent adenosine triphosphatase: an enzyme marker for ovine T lymphocytes.

Sheep T lymphocytes showed a cell surface magnesium-dependent adenosine triphosphatase (Mg2+-ATPase) reaction, which is reported to be characteristic of human B lymphocytes. In cryostat sections of lymph nodes, spleen and thymus, Mg2+-ATPase positive regions closely matched those labelled by sheep pan T monoclonal antibodies (Moab). An Mg2+-ATPase reaction was also found in fibroblastic recticulum cells of T cell regions in lymph nodes. Double labelling of cells from peripheral blood and peripheral lymph for Mg2+-ATPase and the pan T marker showed that 78% of the lymphocytes were positive for both of these markers. In cell suspensions enriched for B lymphocytes the percentage of cells positively labelled was decreased to 37%. Samples of each cell population which were labelled with a pan T Moab and analysed by flow microfluorometry revealed T cell levels which were not significantly different from those obtained by histochemical or immunohistochemical techniques. Less than 1% of lymphocytes positive for heavy and light chains of immunoglobulin (Ig) G were labelled with Mg2+-ATPase. Veiled cells in lymph and monocytes showed a cytoplasmic Mg2+-ATPase reaction.

Analysis of ovine peripheral blood lymphocyte subsets following Ficoll-Hypaque separation or erythrocyte lysis.

Peripheral blood lymphocyte subsets were analysed with the aid of monoclonal antibodies and flow microfluorometry following separation by either the Ficoll-Hypaque method or erythrocyte lysis of the buffy coat. The percentage of lymphocytes labelled by the monoclonal antibodies SBU-T1, SBU-T4 and SBU-T8 were significantly greater (P less than 0.05) in samples obtained by erythrocyte lysis. In contrast, a lower percentage of lymphocytes was labelled by SBU-T6 following erythrocyte lysis (P less than 0.02). These data suggest caution when choosing a method for separation of peripheral blood lymphocytes.

Chronic nephritis in a horse.

An 11 year old Anglo-Arabian mare was presented with a five month history of gradual weight loss and inappetence. On physical examination the mare was in fair body condition with no localising signs of illness. Persistently elevated blood urea nitrogen and isothenuria indicated the presence of primary renal failure. At necropsy both kidneys were shrunken and contracted. Histopathology revealed lesions consistent with end stage renal disease which were characterised by severe and diffuse interstitial fibrosis.