Why do endemic livestock diseases persist? An interdisciplinary perspective

Epidemiology is a field in which the aim is to identify the characteristics, causes and means of control of conditions that exist outside of physiological norms. For both infectious and non-infectious diseases, genetic, physiological, environmental, and behavioural factors can all influence the risk of acquiring disease, meaning that, despite differences in how they manifest, the problems and solutions associated with them can be remarkably similar. Epidemiology has always made use of ideas and techniques from other disciplines that help to achieve its aims, but typically takes a “toolbox” approach, bringing in data, techniques and methods and insights that support epidemiologists to solve problems they already perceive as important. However, it is not necessarily sufficient for tackling “wicked” disease problems which may require long-term investments in interdisciplinary teams, with members working together in finding shared solutions to disease, and to educate and be educated in different disciplinary perspectives on the problem. For endemic diseases in particular, while methods of control and even eradication do exist it is often the case that they are not put into practice. Here, we address two exemplar endemic diseases in the context of farming in England: Bovine Viral Diarrhoea (BVD) in cows, and lameness in cattle and sheep. These diseases were selected because of their significance to UK livestock agriculture and their contrasting epidemiologies. Both are highly impactful and have been recognised for at least half a century as among the biggest threats to livestock health, welfare and productivity in England. In both cases, while historically embedded social factors have been central to their persistence, the reluctance of social scientists and and historians to issue normative guidelines means that they are less able to offer explicit advice to policy, hindering the adoption of broader interdisciplinary perspectives. To fill some of the gaps in that advice, here we suggest approaches to bringing a broad range of observers to bear on them. First, while BVD and lameness are both quite well understood and ‘educating’ farmers (as often advocated in studies informed by ‘theory of planned behaviour approaches’) by treating veterinary perspectives as normative is unlikely to be universally successful. Farmers’ perspectives often have their own logics that are informed by individual circumstances and past experiences which veterinarians and other advisors can fail to appreciate. Second, we note that both farmers and consumers have shown they value health in terms of impacts on welfare and production, however ‘welfare’, like ‘health’ is likely to be perceived differently by farmers compared to veterinarians, and this requires further study. Finally, the new policy contexts of animal health as public good presents important opportunities. Beyond these general lessons, there are also particular issues for each disease. For BVD, with the uneven distribution of costs and benefits, differences in farming perspectives make it highly unlikely that the industry will come together around a voluntary BVD eradication scheme that rests on testing and trading controls. and much can be learned from the countries that are already on that journey or have reached their destination. By contrast, for lameness, where risk-factors are multi-factorial and usually highly localized, universal approaches make little sense. Here, industry-led schemes make more sense because lameness control (unlike BVD) is not a zero-sum game. Moreover, because lameness is pathologically and epidemiologically complex, and rooted in farming systems that can be difficult to change substantially, eradication is extremely hard if not impossible to achieve so local measures make more sense. In both cases, greater understanding of farmer priorities can help to identify ways to make farmers and other farm-based actors such as family members and farm workers more amenable to scientific advances, by identifying (ahead of time) potential barriers. Animal disease problems inevitably involve a complex presentation of natural and behavioural factors. By working together, we have been better placed to understand how those pieces can fit together.