Plenary Session II: Joint Human-Animal Wildlife Assessments on Zoonotic Diseases
Chaired by Martyn Jeggo
This session began with a talk by Jakob Zinsstag on how examining the theoretical underpinnings of One Health can help understand its potential. In his 'One Medicine', Calvin Schwabe noted the biological closeness of animals and humans. He believed that there is no difference in paradigm between human and animal medicine. In fact, it is notable that the human genome is 99 per cent the same as that of the great apes and 95 per cent the same as that of pigs. This may help explain the co-creational attitude of the ancient Egyptians, but modern animal welfare has its origins in South German protestant pietism, as well as Albert Schweitzer's advocacy of respect for life. Nevertheless, there are many discrepancies in the value that humans give to animals, and they tend to be culturally determined. Although the intensification of livestock production may be inhumane, for many small farmers it is a way out of the poverty trap. Humanity attributes widely varying emotional and economic values to animals: could this be the start of a new subjectivism in science?
Regarding costs, a new article entitled A One Health Framework for Estimating the Economic Costs of Zoonosis is about to appear in the journal EcoHealth. One of its conclusions is that rabies control by vaccinating dogs as well as humans may have high initial costs, but it is much more effective than only vaccinating humans. Hence, the wider benefits need to be compared with the costs. For example, this approach increases the benefit-cost ratio of vaccinating livestock in Mongolia. To understand the benefits and costs, an animal human transmission model needs to be supplemented by a multi-sectoral economic model.
We must recognise the inextricable linkage between humans, livestock, companion animals and wildlife. In our work, added value must be demonstrated. These are the necessary conditions for establishing One Health as a science that is not reductionist.
Delia Grace considered international agricultural research in relation to associated diseases. In the latter half of the 20th century fear of a Malthusian crisis led to massive efforts to increase the food supply. However, the more people who are fed successfully, the more health problems arise from intensive ways of growing and producing food. An enquiry into this is being led by the International Food Policy Research Institute (Washington, DC) and the International Livestock Research Institute. It transpires that livestock are potent forces for both good and evil. As income grows, so does demand for meat and milk. Livestock demand is very dynamic. Sub-Saharan Africa and Southeast Asia dominate world growth in intensive monoculture systems. The result is huge vulnerability and lack of security of the food chain. In poor countries 40 per cent of disease is infective and 5 per cent comes from animals. Of the total disease burden, 2.5 per cent is zoonotic, and much of that is under-reported. Food safety is paradoxical: studies suggest that in some countries it may be better in traditional markets than in modern supermarkets.
Control of zoonoses often does not work. The epidemics may cure themselves eventually, irrespective of measures adopted. It is essential that in promoting the One Health ideal, new structures are not founded if they could lead to overlapping mandates and inefficiencies. However, One Health requires considerable change and investment in change. The evidence base is still very thin: successful case studies are only just above the level of anecdote.
Bernard Vallat noted that in Lyons Louis XV of France created the world's first veterinary medicine school. Despite opposition to the move, he was swayed by the argument that it would help understand issues of human health. Nowadays, there is an altered equilibrium between humans, domestic animals and wildlife. Some 75 per cent of emerging infectious diseases have a zoonotic origin. Moreover, 80 per cent of agents with potential for use by biological terrorists have an animal origin. OIE promotes veterinary services and their governmental partners. The aim is to protect and improve animal health, including that of wildlife. This requires that surveillance and early detection be increased. Wildlife and domestic populations have different health statuses. Key tools for assessment include standards and safe trading mechanisms. It is important to promote the harmonisation of national legislation worldwide. The companion programme of standard setting is capacity building. In Europe, one success story of these processes is rabies control. Harmonisation of standards seeks to minimise risks in the relationship between humans, domestic animals and wildlife, and thus to reduce disease transmission. In this process, it is important to safeguard biological diversity and threatened species. Wildlife diseases will shortly become notifiable and listed by OIE, which releases a wildlife report annually. In another development, the agricultural ministers of the G20 have released a declaration on inter-agency co-operation to ensure food security.
Michael Manfredo noted that the human-animal interface is complex and dynamically changing. In the USA the hunting and fishing industry is worth $66 billion annually. The protection and exploitation of wildlife is managed at the state level. In the modern world, what is 'natural' in wildlife systems is socially defined. Wildlife is now less a source of food and material, and more a source of companionship. Thus the need for affiliation has grown in modern society and this is an important transition. The utilitarian approach to wildlife contrasts with the mutualist (or egalitarian) one. Both may be present in the same state. The richer the state, the higher the level of mutualism present in it: this is the modernisation theory. However, there are conflicting views of what is right. Mutualism leads to increasing biological diversity, but with risks from predators and disease transmission.
Francisco Reviriego described the application of the One Health concept in the European Union. He explained the work of the EC Directorate General for Health and Consumers. The EC has realised that there is a need for a holistic approach. A formal position was taken in 2011 and an action plan was produced. It was, perhaps, a late action, but it did propose twelve actions.