ONE WORLD, ONE HEALTH

Epizootics, Zoonosis and Epidemics

Hygia pecoris, Salus Populis
Miguel A. Márquez
Mexico

The emerging challenge of old and new transboundery zoonotic diseases in a globalized world

Zoonosis (Greek: zoon animal; nosos disease), is defined as an infectious disease in animals that can be transmitted to people. The natural reservoir for the infectious agent is an animal. Examples of zoonoses include rabies (a viral disease that can be transmitted to humans through an infected animal's bite) and psittacosis (a chlamydial infection resembling influenza that is spread to humans by the droppings of infected birds). Anthrax for example, is a zoonosis too. It normally affects animals, especially ruminants (such as goats, cattle, sheep, and horses), but can be transmitted to humans by contact with infected animals or their products or by biological warfare.

As mankind expands and human population explodes, economic development proceeds in certain subsectors of the population and new technologies arise, societies around the globe face more complex and previously unknown challenges. Without a doubt human population is experiencing a rapidly evolving world: a place where domestic struggles meet regional priorities that are moulded by international concerns and global issues. We now face climatic change, energy insecurity, nuclear proliferation, hegemonic contestation, deepening regionalism, international terrorism, radicalism, a new multipolar order, and novel diseases.

In other words, the emergence of zoonotic diseases such as Nipah virus in 1999 in Malaysia, Severe Acute Respiratory Syndrome (SARS) in 2002 in China, Monkey Pox in mid 2003 in the United States, Highly Pathogenic Avian Influenza A virus subtype H5N1 (HPAI H5N1) during the second semeter of 2003 in Southeast Asia and also in Europe and Africa, and finally the Pandemic Influenza virus A/H1N1 in March-April 2009 in San Diego and Mexico City, that later extended to North America and the rest of the world, have heightened public awareness of the multidimensional relationship between wild animals, livestock production and global public health.

In an increasingly affluent, informed and interconnected world heading towards nine billion by year 2050, animal production systems of all types will be pressed to provide the kind of high quality protein people crave. Moreover, as four billion people in countries with emerging economies move slowly out of poverty, global meat consumption will grow at about five millions metric tons per year; while globally, in 2009, it reached about 280 millions metric tons. In fact recently, a report by the International Panel for Sustainable Resource Management (IPSRM) titled Environmental Impacts of Consumption and Production concluded that energy, in the form of fossil fuels, and agriculture, especially the raising of livestock for meat and dairy products, are the two areas currently having a disproportionately high impact on people and the planet’s life support systems. This and other publications provide further evidence that, as academics, opinion leaders, influential institutions, scholars and civic actions groups advocate for transformational measures to mitigate impacts and reduce pressures on the environment, the forthcoming decades will bring more extraodinary changes.

Despite strong economic incentives, excessive livestock production to meet growing demand of food animals can exacerbate problems of soil degradation, forest encroachment via deforestation and land clearing, biological impoverishment, and through overgrazing and intensive feed production, a loss in the soil’s ability to sequester carbon, as well as reductions in the amounts of cereals available for human consumption. As of right now, world agricultural production accounts for 18 percent of the total greenhouse gas emissions that are contributing to atmospheric imbalances and 60 percent of the phosphorus and nitrogen pollution.

For comparison, the largest contributor to greenhouse gases is the world energy sector with 62 percent of total emissions, according to the United Nations Environmental Programme (UNEP). Ironically, as if this is not enough, further climatic changes are expected to affect agricultural production via water and heat stress, and changes in the spread of diseases, infections and pests. In summary, as concentrations of atmospheric gases reach record levels, global temperatures are expected to increase by 1.8 to 5.8°C by the end of this century. The hydrologic cycle will be altered, since warmer air can retain more moisture than cooler air. This means that some geographic areas will have more rainfall, while others more drought and severe weather events. If this comes true in the future, rising temperatures and changing rainfall patterns will have a substantial effect on the burden of infectious diseases that are transmitted by insect vectors, contaminated waters, and through humid-environment macroparasites.

As global public health is repositioned in international agendas, it is imperative for disease emergence not be looked at in isolation, but must now be systematically viewed alongside dynamic changes in farming landscapes, animal agriculture intensifications, natural resource depletions, land utilisation patterns, trade globalization, human behaviours, food consumption, and evolving trends in agricultural production, distribution and marketing systems. Attention to and analysis of these changes will reveal the feasible and viable options to address the root causes that underpin pathogen evolution, establishment and persistence.

Additionally, with population growth and labour opportunities arising in urban centres, mass movements within resource-poor countries against a backdrop of collapsed public health systems can create devastating epidemics. Migrants in their cross (country treks are exposed to disease vectors to which they have little resistance, and the diseases they pick up then move with them to their new places of residence) also infecting the people already living in that area. Conversely, individuals travelling between countries and continents for business or pleasure may find themselves in the midst of new urban centres within few hours, but for less than the incubation period for a typical infection to ensue. We must admit that these changes will drive our approach and actions.

Another factor to consider is that there are communities who have gotten used to recurrent natural disasters and living with infectious diseases who have developed deeply embedded understandings of risks and resilience that ultimately influence the way they view and respond to hazards and threats. It is for this reason that cultural and social dimensions must be adopted, leveraged and made central to bring people, with their incentives and motivations, back into spotlight. In years to come, an important challenge in veterinary public health will be to balance the need for adequate population intake of animal-source protein and essential nutrients with the rapid selection, amplification and spread of pathogens in animal production systems. Evidently, addressing disease burdens on host populations must also consider livelihoods, poverty alleviation, food security, animal welfare and environmental protection while constantly reassessing successes, failures, threats and opportunities.

We must recognize that decades of extraordinary scientific and technological progress now grant collective confidence that development and diffusion of best practices and continuing innovation can advance our world much further in forecasting emerging zoonotic diseases that arise at the animal-human-ecosystem interface, and also now offers other key directions for a healthy and prosperous environment for all.

Diseases will be always part of our lives. Pathogenic agents need animal, human and plant hosts to survive and thrive. The science and art dealing with the maintenance of health and the prevention, alleviation, or cure of diseases rests firmly on this premise. Veterinary and human medicine have spoken for long to each other, but with the emergence of H5N1 HPAI, and A/H1N1 pandemic influenza viruses, a realization that these two disciplines needed to closely interact became absolute. This is the perfect case that illustrates how health within medical communities was seen then, and how it is perceived now. We can no longer address health independently.

The simple truth is that there is only “One Health and One World”. With this rationale in mind, the Food and Agriculture Organization of the United Nations (FAO), the World Organisation for Animal Health (OIE), the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF), in collaboration with the World Bank and the United Nations System Influenza Coordination (UNSIC), conceptualized the “One World, One Health” approach, which is a collaborative, international, cross-sectoral, multidisciplinary mechanism to address threats and reduce risks of detrimental infectious diseases at the animal-human-ecosystem interface.

It strategically builds on the lessons learned from, and achievements of, the responses to the H5N1 epizootic and the H1N1 epidemic. This approach is acknowledged as a feasible and viable model to address the multidimensional challenges that are rapidly evolving in a changing world. While some regions are bound to benefit more than others, it is expected that the potential for One Health approaches to reduce disease burdens might be greater in specific hotspots, especially in developing countries in the tropics, than those estimated in studies conducted in developed countries.

Although very likely to deliver substantial benefits to animal and human health and the
environment, One Health will probably encounter commercial, cultural, and political resistance, and face numerous technical and logistical challenges. However, as all great movements and initiatives in history, “One World, One Health” shall prevail.


One World, One Medicine, One Health
Healthy Animals, Healthy People
One Profession, One Vision, One Voice



Miguel A. Márquez
México
October, 2010
miguelmarquez42@hotmail.com