Plenary Session VII: Urban Health - One Health: Intersectoral and Interdisciplinary Challenges

Chaired by Oliver Hagon

Roderick Lawrence inaugurated the session with a talk on the interdisciplinary aspects of urban health management. Urban health has a long history. In 19th century Europe there was a historic fight against infectious diseases, such as cholera and tuberculosis. There was explicit collaboration between professionals in medicine, public health, and engineering, and proponents of the housing reform movement. Such collaborations are needed again now. 'Multidisciplinary', 'interdisciplinary' and 'transdisciplinary' are not synonyms and need to be distinguished from one another. The health status of urban populations is the result of many factors, whose relative importance differs from that which they have in the rural environment. Population density in cities is proportional ton contagion. Intra-urban health differences are significant in cities in many different countries throughout the wealth spectrum. The difference in life expectancy between adjoining neighbourhoods can be as much as ten years.

One quarter of the global burden of disease can be attributed to environmental factors. Human ecology can provide the broader perspective that we need in order to understand the problems involved. There are cross-boundary linkages between dimensions of the natural and built environment, and with transportation policy. Studies of human ecology in Chicago and Hong Kong were seminal in revealing the linkages. In this respect, 'multidisciplinary' refers to the juxtaposition of disciplines; 'interdisciplinary' to their overlapping, with integration and collaboration; and 'transdisciplinary' goes beyond the academic aspects to include practical know-how. It is important to integrate academic knowledge, not juxtapose it.

Nino K├╝nzli spoke on the subject of traffic management in the urban environment considered as a One Health problem. In order for us to respect health and the integrity of humans, animals and ecology, traffic research must necessarily be transdisciplinary. Road accidents are the ninth leading cause of death in the modern world, but they look set to rise to fourth or fifth position. Worldwide, there are 10-30 deaths per 100,000 of the population. Injuries are more numerous and 10-20 per cent of them lead to disability. Pedestrians tend to be forgotten in the management of traffic, and so do animals. Hence, traffic is correlated with obesity. Moreover, road traffic is a leading source of urban air pollution, the peak values of which are experienced within a few tens of metres of busy roads. Air pollutants jeopardise the ability of the immune system to combat infectious diseases. This leads to "the silent every-day epidemic". In Barcelona, for example, there is an average of ten premature deaths a day as a result of air pollution. Worldwide, more than 800,000 premature deaths a year are attributable to air pollution. The impact is therefore larger than that of traffic accidents.

Pollution and accidents are not the inevitable price of prosperity. Swiss studies show that improved air quality leads to better health and it can be combined with rising prosperity. Air pollution causes crop yield losses of 3-12 per cent and is thus also a food security issue. Moreover, smog pollution kills cattle as well as people.

Mark Rosenberg described how urbanisation, now encompassing the majority of the world's population will by mid-century rise to 70 per cent of people. There are already 27 'megacities' with populations of more than ten million inhabitants. The migration of the rural poor and their livestock to urban areas can bring pathogens to the city. More than one third of the world's drinking water supply is lost before it reaches consumers. This amounts to 32 billion litres a year. Thus, although we have the technology to produce clean water in quantity, we still have enormous problems in delivering it. Moreover, one third of the global population lives in urban slums. We need models and surveillance systems for threats to human health in urban areas. It is as well to remember that every improvement to urban infrastructure is a siren call to the disadvantaged residents of rural areas who are contemplating moving to the city.

Virginia Murray talked about extreme events and disaster management as an interdisciplinary challenge. The UK Health Protection Agency is a front-line body. Its aims are to reduce key infections and to minimise the health impacts of environmental hazards and extreme events. It coordinates investigations and the control of outbreaks. Finally, it advises government and responds to international health research. HPA has dealt with floods, heatwaves, droughts and cold spells. The last of these prematurely killed 27,000 people in the UK during the winter of 2010-11. Disaster risk is made up of the nature and severity of the event, together with vulnerability and exposure. The natural variability and anthropogenic change of climate are important drivers. Disaster risk management is therefore closely linked to climate change adaptation.

European heatwaves are an urban issue. Climate models predict that there will be more frequent hot days throughout the 21st century. Heavy rain and prolonged drought will also intensify. This requires better risk management and adaptation. Sustainable management must be practised with respect to water, farming and crops. Improved forecasting is also a necessary prelude. In disaster risk reduction and the IPCC, health issues have been neglected.

The One Health community could derive significant inspiration from the UNISDR's Hyogo Framework for Action (HFA), which has 168 national signatories. The HFA has five key points: creating governance and giving priority to disaster risk reduction; knowing risk and taking action; building understanding and awareness; reducing underlying risk factors; and being prepared and ready to act. These are very pertinent to the One health agenda, as are sustainability and the Millennium development goals. Tools have been developed by HPA to help manage disasters and health issues. Communicable diseases, nutrition and climate risk management are three of the 17 topics covered in short, practical documents. WHO has produced country-level assessments of crisis management capacity. Worldwide, natural hazards and extreme events have an increasing impact on human health, of which One Health is a part. This offers an interdisciplinary challenge, especially as climate change will affect health and health systems. Taking inspiration from the Hyogo Framework for Action, a One Health 'umbrella' could be created.