William Karesh, BBC Green Room 27 Jul 09;
Geographic and environmental boundaries that once protected us from widespread disease outbreaks are no more, says William Karesh. In this week's Green Room, he calls for the West to adopt a "prevention is better than cure" approach to human and animal health.
During the 1918 Spanish Flu pandemic that killed up to 100 million people worldwide, children sang a nursery rhyme: "I had a little bird, Its name was Enza, I opened the window, and in-flu-enza."
Today, the expanding human population and activity has opened the pandemic "window" even wider.
A major component of any strategy to protect ourselves must involve treating disease before it gets to us.
We are reminded by the recent World Health Organization designation of a H1N1 pandemic that infectious diseases have little regard for the Darwinian divide.
Humans share more than 60% of "known" infectious organisms with animals, and the majority of new or emerging diseases are linked in some way to wild animals; ebola, HIV/Aids, Sars, and Avian influenza are just a few examples.
But don't blame the animals; these diseases in humans stem from how we move about the planet, interact with animals and the environment, educate our citizens, provide or don't provide health services, and deal with poverty and hunger.
Going global
Animal health is tightly linked to the conditions of its surrounding environment, and humans are increasingly changing or affecting those conditions.
The trade in wildlife for food, traditional medicine, or pets, for example, has increased in response to human demand.
This flourishing trade - both legal and illegal - of domesticated animals, wildlife and wild animal parts is often marked by unsanitary conditions that can give rise to zoonotic diseases (those transmitted from animals to people).
As modern transportation is made available to more of the world, geographic boundaries that once protected us from remote disease outbreaks are nearly obsolete.
Viruses and bacteria long confined to living in a single species, or in one part of the world, can now quickly be moved to new areas and thrive in environments, animals or people unprepared for their arrival.
Other human-induced environmental conditions can have an effect as well, and are not predicated on human physical presence in a specific place.
Disturbances, such as fluctuating precipitation levels and increasing temperatures brought about by climate change, can have far reaching consequences on ecosystems and animal health, and thus, ultimately drive changes in disease proliferation and redistribution.
Not surprisingly, predicting outbreaks of zoonotic diseases is an increasingly complex, but critically important, undertaking.
It is a mistake to believe that stockpiling vaccines or drugs will be enough to ensure that we are protected from future pandemic threats.
The next pandemic may not come in the form of an influenza virus. There is no guarantee that in response to a viral threat, we will have time to modify a vaccine or that current drugs will remain effective.
Many of us have been actively promoting the concept of One World, One Health - a philosophy that dictates a comprehensive approach to pandemic preparedness that starts "upstream", and attacks disease at its origins.
That means working with people in the poorest areas of the world who have little access to health care for themselves or their livestock, or to proper hygienic provisions for raising and handling animals.
In many of these places, the order of the day is simply survival.
To really protect those of us "downstream", in places like the US and Europe, from emerging pandemic diseases, we must focus a portion of our efforts on collaborating with those upstream populations to create a safer and healthier future.
This means building capacity in the developing world to monitor wildlife, domestic animals and people for disease.
It also means giving those living at the frontlines of an outbreak the ability to respond.
This may sound like an ominous task, but in the long run, preventing or solving a potential pandemic disease crisis at its source will prove far more cost effective than paying for the effects after its devastating impacts.
The nascent beginnings of such a comprehensive, global approach to pandemic disease have been initiated by the US government and a number of UN agencies.
Formal and informal networks of public health agencies, infectious disease scientists, veterinarians, conservation organisations and technology firms are sharing resources and enabling access to disease distribution data, sample analyses and outbreak information.
This is vital to predicting, identifying and responding to new emerging diseases in countries most in need of help and at the highest risk.
As with climate change, we are learning that what we do locally affects our global community, and that all nations both developed and developing, will play an important role in the future condition of our shared planet.
Working as partners within a One World, One Health philosophy is a critical approach to answering our environmental challenges - including minimising the impacts of a future pandemic.
Just as we share the planet's atmosphere, we share all of its infectious organisms.
Dr William B Karesh is vice president of the Wildlife Conservation Society and director of its Global Health Program
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
