Where the Wild Things Are

National governments are also beginning to acknowledge the links among wildlife, domestic animal, ecosystem, and human health and the resulting need to address the threat of disease across sectors. In October 2007, the Brazilian government held its first One World-One Health congress, which brought together the ministries of agriculture, environment, and health along with major livestock producers. One outcome of the Brazil meeting was the increased recognition that forest degradation can not only lead to an increase in greenhouse gases but also act as a driver of both wildlife and human disease. For example, clearing tropical forests can create breeding grounds for several types of Anopheles mosquitoes that carry malaria.

In the United States, the Centers for Disease Control created the National Center for Zoonotic, Vector-Borne, and Enteric Diseases in 2007. Staffed with more than 600 epidemiologists, physicians, and veterinarians, this new center brings together some of the oldest components of the agency -- those dealing with viral, bacterial, parasitic, and other communicable diseases -- to examine diseases that can affect both wildlife and humans within a larger ecologic context.

Improvements in global information-sharing have allowed scientists from around the world to more easily communicate findings and ideas, an essential step toward meeting the challenge of protecting people and animals from infectious diseases. New networks for sharing viral gene sequences are beginning to release the world from the old system of having to wait for a few individuals to identify a new pathogen or for them to publish their findings a year or two later in a scientific journal. With the H1N1 outbreak, as soon as the new strain was identified, its genetic code was transmitted to influenza experts around the world for further evaluation.    

When avian influenza emerged in 2005, scientists and researchers had little information on how common it was and where it was occurring in wild and domestic birds. Those studying the disease needed to know where wild birds were migrating and whether they carried the virus from its incubation points in large duck and chicken farms. The creation of the Global Avian Influenza Network for Surveillance in 2006 was designed to answer some of these questions. Participants from 30 GAINS partner organizations around the world have since recorded the movements and locations of more than 100 million wild birds and collected over 40,000 samples for influenza testing. These findings are available in a public database and mapping system. For the first time in history, thousands of people from government agencies, universities, and NGOs have been trained to safely and effectively participate in a global wildlife-health-monitoring system.

Expanding this approach to a wide range of diseases would enhance the early detection of new diseases, as well as the occurrence of known diseases in new places, and help to rapidly identify the genetic origins of pathogens. The U.S. Agency for International Development is now using GAINS as a model for a new program designed to predict and respond to diseases emerging from animals around the world. It will focus on building local capacity in places such as the Amazon basin, Asia, and the Congo basin, where diseases such as avian influenza, Ebola hemorrhagic fever, SARS, and HIV/AIDS first emerged.    

New challenges will continue to arise. Climate change, for example, is a concern not only because of the environmental fallout but also because warmer temperatures and altered rainfall levels may foster the spread and emergence of infectious diseases. Wildlife may be the canary in the coal mine for the dangers of climate change: even minor disturbances in the environment can influence its susceptibility to disease. Microbes are even more responsive; temperature and rainfall patterns significantly affect the viability of viruses, bacteria, and parasites. Little data currently exists on how diseases will spread in response to climate change. To uncover such trends, disease surveillance efforts should be examined together with meteorological data. 

The drivers of global change -- namely, population growth, expanding agriculture and livestock production, wildlife trade, biodiversity loss, and climate change -- all disturb the balance of disease pathogens in the world's ecosystems. Scientists are beginning to gain a better understanding of the vulnerabilities of certain species, disease transmission routes, and ways to prevent disease problems from occurring.

But there is a long way to go. Organisms dangerous to people and animals continue to mutate, adapt, and spread, and opportunities for new diseases to emerge and travel globally are increasing. In response, it is necessary to quickly build new partnerships and strengthen capabilities for global health surveillance that are not limited to disease in humans. It is equally important to find innovative ways of using that information to more effectively protect the health of wildlife, domestic animals, and people everywhere.