View all veterinary jobs
The Equine Veterinary Journal has published a special early view article reviewing the science behind enhanced equine influenza vaccination schedules, in particular the replacement of annual boosters with a mandatory bi-annual vaccination programme.The article argues that as the equine influenza (EI) vaccine supply returns to normal, there is sound scientific evidence why bi-annual vaccination schedules should be re-implemented promptly.
Whilst the scale and number of outbreaks has been relatively small since the introduction of mandatory EI vaccination by most competitive equestrian disciplines in the 1980s, disease events such as those experienced in the UK in 1989, 2003 and most recently in 2019 have demonstrated EI’s epidemic potential, even in vaccinated horse populations.
In their article 'Equine influenza bi-annual boosters: what does the evidence tell us?' Victoria Colgate and Richard Newton discuss what has been learnt from previous outbreaks and explain the evidence from mathematical models to show why bi-annual boosters are beneficial.
The authors say that epidemiological data from previous natural EI outbreaks have repeatedly demonstrated the impermanent nature of the protection provided by vaccination and observational field studies have repeatedly highlighted the potential for 12-monthly boosters to leave a vulnerable immunity gap at both the individual animal and population level.
Mathematical models of EI transmission confirm that six-monthly rather than annual EI booster vaccinations are preferable to establish and maintain effective population level immunity to EI.
Ideally vaccine strains should be updated in a timely manner to ensure inclusion of the most epidemiologically-relevant strains, however, this is a slow and expensive process for equine vaccine manufacturers.
In the absence of updated vaccine strains, bi-annual vaccination is strongly recommended to help compensate for antigenic drift between vaccine and circulating EI viral strains
Professor Celia Marr, Editor of the EVJ said: “Although the recent EI vaccine shortage has necessitated a temporary relaxation of competition vaccine schedules, we must now renew the message that six-monthly boosters are optimal and necessary.”
The Editorial can be found at https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.13898 and is free to view.
Two related articles can be found here: https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.13874 and here: https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.13885
Until now, research in equine veterinary science has focused primarily on the information needed to prevent and cure disease, with little attention paid to the attitudes and actions of horse owners, veterinary surgeons, and numerous other professionals to implementing science-based advice.
This special EVJ collection showcases studies that seek to understand horse owner behaviour around their horse’s health, supplementing clinical evidence with information about the real-life behaviours of equine owners and professionals and the factors that influence them.
It includes papers on horse owner knowledge and opinions on recognising colic, treating infectious disease, uptake of some of the most basic preventive health measures such as vaccination and deworming as well as attitudes and behaviour around equine obesity and laminitis.
Other studies highlight the importance of professionals other than vets such as farriers, equine podiatrists, physiotherapists, dental technicians, chiropractors, and equestrian organisations such as the British Horse Society.
Guest Editor Tamzin Furtado added: “As our understanding of the drivers of behaviour develops, pre-existing behaviour change models will help us to understand the barriers and enablers to uptake.
“With dissemination of this knowledge, we have a better chance of communicating effectively and implementing change that will have a positive impact on equine welfare at individual, community, and national level.”
Professor Celia Marr, Editor of the EVJ said: “This collection is both compelling and eye-opening.
"It is dangerous to assume an understanding of the motivators of horse owner behaviours and actions; these papers confirm the current lack of comprehension, providing an invaluable insight, which will ultimately help us to accelerate improvements in equine veterinary practice and, most importantly, equine welfare.”
The virtual issue can be found at https://beva.onlinelibrary.wiley.com/doi/toc/10.1001/(ISSN)2042-3306.owner-behaviours and will be free to view until 26 December 2022.
Two equine journals have joined forces to create a free online collection of their recent articles on endocrinology to raise awareness of these common disorders and to provide veterinary surgeons with what they say is a definitive source of references all in one place.
The collection of references published by Equine Veterinary Education (EVE) and Equine Veterinary Journal (EVJ) covers a range of topics within the field of endocrinology and includes authoritative review articles on insulin dysregulation2, glucocorticoids and laminitis3 and paraneoplastic syndromes4.
The initiative has been made possible with the support of British Equine Veterinary Association Trust and has been compiled by leading international authorities on equine endocrinology, Professor Philip Johnson, of University of Missouri and Professor Nicholas Frank of Tufts University, Boston and the University of Nottingham.
They say that equine endocrine disorders, such as Pituitary pars intermedia dysfunction (PPID), are becoming more promptly identified and treated, thanks to ongoing research and advances in diagnosis, pharmacokinetics and management protocols.
PPID, or Cushing's, is a progressive neurodegenerative condition that is more easily recognised in its advanced form in older horses. Surveys show a PPID prevalence rate of up to 22% in horses over the age of 155, with the odds of developing clinical signs associated with PPID increasing by approximately 20% per year after this age.
Insulin dysregulation (ID), characterised by increased insulin response to oral sugars, hyperinsulinaemia and insulin resistance, is identified in both PPID and equine metabolic syndrome (EMS)2. Both PPID and EMS have been linked to the development of recurrent laminitis with subsequent high risk of mortality6. The exact mechanisms which link insulin to laminitis remain to be clarified1 but this online collection highlights several studies, which partially address this important jigsaw7-12.
Best practice for the management of EMS is outlined by Professors Nick Frank and Ray Geor in the December issue of EVE13. The first goal is to induce weight loss, and guidelines for designing diets for obese equids are provided. Exercise and dietary management14 have been shown to reduce the clinical signs and indices of inflammation in equine metabolic syndrome13 - 15, however, further studies are needed to quantify the efficacy of these management changes on long-term outcomes.
The online collection also includes several studies addressing the diagnosis of PPID. The value of plasma adrenocorticotropin hormone (ACTH), when interpreted with seasonally adjusted reference ranges, is discussed by several authors18-20. Professors Frank and Geor advocate it as the most readily accessible test for monitoring PPID cases in a field setting, although they maintain that the thyrotropin- releasing hormone (TRH) stimulation test is more sensitive and therefore has advantages when diagnosing PPID in its early stages13.
Pergolide has emerged as the drug of first choice for treatment of PPID13. While many vets recommend the early introduction of medication in the hope that it may avert the specter of laminitis, at present, there are no trials comparing pergolide with alternatives. Furthermore, there have been no long-term studies to show that horses treated with pergolide before the onset of clinical signs of PPID have better outcomes, including a reduced incidence of developing laminitis, than horses in which treatment is delayed until clinical signs become apparent.
Professor Celia Marr, Editor of Equine Veterinary Journal said: "Better control of PPID and insulin dysregulation should lower the risk of laminitis to help improve the health and longevity of many predisposed horses and ponies.
"Raising awareness of the benefits of early diagnosis and sharing the latest research on these and other associated conditions are imperative to provide horse owners with the best diagnostic and treatment programmes for their horses. However, it is easy to under-estimate obesity: horse owners need to think about improving management of their horses' feeding and exercise in order to avert problems before they become a veterinary issue."
References