The Human-Animal Link

William B. Karesh and Robert A. Cook

From Foreign Affairs, July/August 2005

Summary:  Recent outbreaks of avian flu, SARS, the Ebola virus, and mad cow disease wreaked havoc on global trade and transport. They also all originated in animals. Humanity today is acutely vulnerable to diseases that start off in other species, yet our health care remains dangerously blinkered. It is time for a new, global approach.

William B. Karesh is Director of the Field Veterinary Program at the Wildlife Conservation Society and Co-chair of the World Conservation Union's Veterinary Specialist Group. Robert A. Cook is Vice President of and Chief Veterinarian at the Wildlife Conservation Society.

RISING TO THE OCCASION

As many of these examples suggest, preventing or controlling future outbreaks of animal-borne diseases and mitigating their impact will require a far broader approach than has so far been attempted by the generally isolated health systems of highly developed countries. Too often, the global response to new pathogens has been driven by fear, which has only magnified the economic and other costs of disease control.

That said, a few brave individuals have already begun the process of creating a new international and interdisciplinary approach to disease control. Working in some of the most remote places on earth, they have slowly established knowledge-sharing networks, such as the World Conservation Union's Veterinary Specialist Group. And their contributions have already been significant. For example, when avian influenza first appeared, much attention was mistakenly directed at controlling its spread among wild birds in Northeast and Southeast Asia. It was these new informal participants in health discussions -- such as conservation biologists and veterinarians working with the Wildlife Conservation Society in Cambodia and linked to staff at the Food and Agriculture Organization -- who were the first to point out that the migratory routes and timing of wild birds did not actually correspond with the spread of the disease and that domestic birds were more likely the culprit. Without this insight, valuable resources would have been wasted trying to control the disease among the wrong animal population.

As important as such contributions have been, however, many individuals trying to develop a new global approach to health-care work for nongovernmental organizations or for local governments lack the resources and a larger, formal network that could fill in the gaps in health care as it relates to wildlife and humanity. Were their resources improved, the results would be enormously beneficial; building bridges across disciplines to solve health problems can have simple but profound effects.

For example, studies in South America have shown that, contrary to common opinion, livestock diseases pose many more threats to wildlife than the other way around. In much of the world, reducing disease in domestic animals would benefit several industries, improve human health and livelihoods, and help safeguard wild animals. As this suggests, strategically increasing protections in one area of health care can benefit another. For example, gorillas and chimpanzees in central Africa have little to no immunity to common human diseases, and so they are endangered by contact with local people and tourists. This risk could be dramatically reduced by implementing good preventive health programs and practices in local villages, which would benefit both people and wildlife. Already, work with the Ebola virus in gorillas and chimpanzees has shown that investments in wildlife health can protect urban human populations; in Africa, animal health workers detected the presence of Ebola in wildlife months before the first human cases occurred, providing critical lead-time to warn villagers not to hunt or handle the animals that were a source of the infection. Such a broad, "one health" approach to disease can be much more effective and inexpensive than the traditional "quarantine and stamping out" strategy for fighting an illness after an outbreak has already begun. Specialists in human and animal health, in conjunction with wildlife conservation professionals, have already developed a set of guiding concepts on these themes, called the Manhattan Principles. But the ideas still need much broader acceptance to be more effective.

To further improve the chances of heading off and limiting the effect of animal-related diseases, a number of additional steps are necessary. To begin with, better worldwide surveillance to detect infectious diseases among wildlife is needed to improve response time and reduce the costs of new outbreaks. Such surveillance differs from traditional hypothesis-driven disease research because it involves very broad searching rather than attempts to answer a highly focused question. Investment in gathering advance information can pay off handsomely; early warning of how diseases work and of their normal characteristics among animals can help limit the damage when the illnesses start to spread.

New public-private partnerships could also be hugely helpful. Currently, the failure of public-sector programs to comprehensively monitor, prevent, and respond to unusual diseases is being compensated for by the private sector. Coordination between these efforts and governments remains limited -- in some cases due to regulations and restrictions that prevent such collaboration. For example, under its agreement with member states, the World Animal Health Organization cannot accept information on wildlife diseases in a country unless that information has been submitted officially by a national agricultural authority -- few of which are mandated or organized to monitor wildlife diseases. These policies should be reformulated to facilitate cooperation among governments, corporations, and nonprofit organizations, and formal mechanisms for sharing information should be established.

It would also help to shift responsibility for the costs of outbreak prevention and control to animal traders, since this would provide them with incentives for reducing disease and would lower the costs of disease surveillance, control, and prevention by third parties. One way to force traders to shoulder more of the costs would be to require them to buy disease outbreak insurance on all animal imports or shipments. Doing so would discourage dangerous activities among animal traders by hitting them where it hurts: in their wallets.

Financial incentives are not enough, however; the World Trade Organization and other appropriate international bodies must also start requiring governments to better regulate the health aspects of international trade in wild and domestic animals. Individual states also need to implement new laws to prevent the spread of diseases within their borders. There is now plenty of evidence to suggest that human trade and consumption of wildlife have led to global health disasters; governments must therefore immediately start making serious efforts both to reduce and to regulate properly the trade of such animals internationally, regionally, and even locally.

On the health-care side, decisions still tend to be made without sufficient input from all appropriate stakeholders. For example, the decision of a Southeast Asian government in 2004 to control avian influenza by culling wild migratory birds failed to identify the real source of the problem (domestic livestock) or to recognize that the wild birds were protected by at least two separate international conventions. Involving experts in public health, agriculture, and environmental conservation, as well as legal counsel, in such decisions would help governments avoid repeating these mistakes and adopt more sound strategies in the future.