09/27/2012 - 19:34

The One Health solution

Laura H. Kahn

Laura H. Kahn



The popular press is finally recognizing the important connections among human, animal, and environmental health. Environmental destruction, global trade and travel, intensive agriculture, and other human activities all lead to the emergence of previously unknown microbes that can infect across species, causing zoonotic disease outbreaks like West Nile virus, avian influenza, hantavirus, HIV/AIDS, and others. No wonder the media is paying attention.

These zoonotic diseases typically emerge from wildlife and occasionally from domestic animals. Most bioterrorism agents, as recognized by the US Centers for Disease Control and Prevention, are zoonotic as well. Think: anthrax, plague, tularemia, the viral hemorrhagic fevers, brucellosis, glanders, psittacosis, Q fever. Adequately addressing these emerging infectious diseases and bioterrorism agents requires a new interdisciplinary approach -- a "One Health" approach.

The One Health movement (which I support and participate in) is based on a simple concept that recognizes the inextricable links among human, animal, and environmental health and calls for professionals in these realms to communicate and collaborate as colleagues. For most nations, that means a paradigm shift in how infectious diseases are approached. Rabies is an excellent example. There are tens of millions of dogs in India; many of which are infected with rabies. One-third of the world's rabies deaths each year (20,000 people) occur in India. A One Health solution would target the dogs -- through sterilization and vaccination -- as a way to control the disease rather than wait for people to become infected through bites. Such a paradigm shift would require changes to institutions, funding, education, and jobs -- changes that will improve global biosurveillance and prevent outbreaks.

Institutions. Many microbes can't tell the difference between humans and other animals, but for over a century, governments, academic institutions, and businesses have built up silos, each with different missions. In the United States, for example, human health is largely overseen by the Health and Human Services Department; its mission is to protect the health of all Americans. But there is no equivalent institution for animal health. A 2005 National Academy of Sciences report, Animal Health at the Crossroads, found that responsibility for animal health in the United States is divided across many different agencies, including the Agriculture Department, the Interior Department, the Defense Department, the Commerce Department, and the Health and Human Services Department -- none of which includes animal health in its core mission. For example, the mission of the Agriculture Department is to protect and promote food, agriculture, natural resources, and related issues. Nowhere does it mention protecting the health of animals -- even though healthy animals contribute to healthy people.

Most governments are arranged this way: Health departments oversee human health; while agriculture departments promote agriculture, not animal health. Few organizations include animal health in their missions. One exception is the World Organization for Animal Health (OIE), the mission of which includes animal disease control. Predictably, the OIE is hindered by a dearth of funding and resources.

Funding. Since missions determine funding priorities, it's not surprising that there are vast discrepancies in human and animal health funding. For example, the 2013 budget for basic and clinical research for human diseases at the National Institutes of Health is $29 billion. But the National Institute of Food and Agriculture has a total 2013 budget for research and education activities of approximately $738 million -- with $0 budgeted for animal health and disease research. This is serious. Some of the greatest discoveries in the history of medicine and public health were made studying animal diseases. For example, the fundamental discovery that diseases could be spread by arthropods like ticks was made by a 19th century physician-veterinarian team studying cattle fever. This monumental finding led the way to the discovery that yellow fever is spread by mosquitoes. Advances in animal disease research leads to improved disease surveillance, treatment, and prevention in both animals and humans. Researchers are starting to recognize this.

At the global level, the World Health Organization and Food and Agriculture Organization receive sizeable billion-dollar-plus budgets. But the OIE had a 2011 budget of approximately $24 million. The OIE is so small, it cannot even place staff in field offices around the world, diminishing its ability to help countries with minimal to no veterinary medical expertise.

It would be unrealistic to expect funding parity between human and animal health. But, given the current vast funding discrepancies, implementing an integrated approach is virtually impossible. Policy makers need to learn that supporting animal and environmental health improves human health.

Education and jobs. Globally, the ratio of medical to veterinary medical schools is roughly the same as it is in the United States: about five to one. This is a concern because there aren't enough veterinarians to put One Health approaches into practice and not enough working physicians and public health professionals interested in doing so.

Some countries lack schools of veterinary medicine altogether and thus have no workforce trained to monitor animal health. Couple this lack of training with a lack of incentive -- few jobs in the veterinary medical specialties that deal with zoonotic diseases and bioterrorism agents -- and there's a perfect and unmonitored situation for microbes to run rampant. In the United States, for example, nearly 80 percent of veterinarians practice pet medicine due to societal demand. While important, companion-animal medicine alone isn't enough. Without funding for animal health institutions and imperatives, there aren't enough jobs in veterinary epidemiology, livestock and wildlife health, or animal disease research to entice veterinary medical graduates to dedicate their careers to them.

A vision for the future. Some organizations are beginning to change the paradigm. The University of Florida is offering a Ph.D. program in public health with a One Health concentration. And the US Defense Department has started integrating zoonotic disease surveillance with biodefense. But these programs are few and far between.

Meanwhile, silos persist. Though organizations that monitor public health might have a veterinarian on staff or access to a veterinary consultant, there are few of the interdisciplinary collaborations needed to make meaningful, lasting improvements in global health -- despite plenty of fiscal incentive. In June 2012, the World Bank issued a report finding that six major zoonotic disease outbreaks occurring between 1997 and 2009 cost at least $80 billion. If these outbreaks had been prevented, the savings would have averaged around $6.7 billion per year. The World Bank further estimated that investments needed for an integrated, preventive approach would cost somewhere between $1.9 to $3.4 billion per year -- substantially less than the cost of the outbreaks. Governments responsible for responding to outbreaks need to realize that One Health could save dollars and lives.