Experts urge collaboration between veterinarians, physicians in wake of emerging zoonotic diseases, potential epidemics.
The One Health Initiative, a movement to forge partnerships between physicians and veterinarians, has been endorsed by various major medical organizations and health agencies, including the CDC, the American Medical Association, the American Veterinary Medical Association and the American Society of Tropical Medicine and Hygiene. Additionally, more than 300 prominent scientists, physicians and veterinarians worldwide have endorsed the initiative.
These endorsements pave the way for the implementation of the One Health Initiatives proposals, which are designed to increase cooperation and reduce communication barriers between physicians and veterinarians.
Experts believe there is a growing need for greater collaboration between physicians and veterinarians. More than 35 of the most recent emerging diseases including Ebola, monkeypox, West Nile virus and SARS have been recognized as zoonotic in origin.
The One Health Initiative is a direct response to increasing concerns about the threat of emerging diseases worldwide and the significant threats such outbreaks pose to the health of humans and domesticated animals. These threats also have the potential to affect regional and global economies.
One of the major goals of the One Health Initiative is the integration of educational systems within and between human medical schools, veterinary medical schools and schools of public health. The initiative also calls for improved cross-disciplinary communication in professional journals, conferences and allied health networks.
More than 35 of the most recent emerging diseases – including West Nile virus – have been recognized as zoonotic in origin.
Source: CDC/Cynthia Goldsmith
Furthermore, the One Health Initiative will promote increased research on cross-species disease transmission and the integration of human, veterinary and wildlife disease surveillance and control systems. The initiative will encourage and foster comparative research on diseases affecting both humans and animals, including diabetes, cancer, autoimmune disorders and obesity.
The initiative encourages partnerships in academia, industry and government for the development and evaluation of new diagnostic methods, medicines and vaccines for the prevention and control of cross-species diseases, along with a joint effort to inform and educate political leaders and the public.
The One Health Initiative Task Force held its first meeting in November 2007.
We are off to an excellent start, Lonnie J. King, DVM, director of the National Center for Zoonotic, Vector-Borne and Enteric Diseases, said in a press release. By the end of our second meeting, we will have completed the framework of a comprehensive report with final recommendations and actions that will support and sustain One Health. This will encourage the veterinary profession to take a leadership role that ensures both the acceptance of the concept and its central purpose of improving the health of humans, animals and the environment on a global basis.
The One Health Initiative will foster partnerships between physicians and veterinarians, leading to better research and surveillance in zoonotic and emerging diseases. Bolstering defenses against emerging human infections of animal origin worldwide is a key objective for global public health.
There are many lessons the two groups can learn from one another, and communication must be improved, James Hughes, MD, director of the global infectious disease program at Emory University in Atlanta and member of the Infectious Disease News editorial advisory board, said in an interview. For example, SARS was a previously unrecognized virus with an animal source, and when it emerged, clinicians and public health officials recognized the need to learn more about coronavirus infections in animals.
The One Health Initiatives concepts stem in part from divisions between medical disciplines that have hampered educational programs, communications campaigns and public health systems.
Clinicians should recognize that if they have a patient with a zoonotic infection, veterinarians could know more about it than they do, Hughes said.
Disciplines converge, divide
Although the dividing line between veterinary and human medicine was not as marked in previous centuries as it is today, a split in the two disciplines formed in the 20th century. Some reasons are geographical; few medical schools and veterinary schools are housed within the same academic setting. Other factors are societal. Ecology and microbiology are not discussed as much in medical school as they are in veterinary school; thus, medical students might not be aware of the importance of zoonotic disease in human health. In addition, veterinary schools have shifted focus from livestock and research to companion animal medicine to meet societal needs.
The concept of One Health has been around for centuries, but collaborations have languished in the 21st century, Roger Mahr, DVM, immediate past American Veterinary Medical Association president, said in a press release. The challenges of the 21st century demand we invigorate it.
Presentations about the initiative were made at the 56th Annual Meeting of the American Society of Tropical Medicine and Hygiene, held recently in Philadelphia.
Experts echoed Mahrs call to action and the need for One Health at this meeting. The interdependency and complexity of our world is demanding a new way of thinking and doing business. That is what we would like to accomplish with the new center, said King. Animal health and public health are a continuum; we must not look at them as separate systems.
Zoonosis through the ages
Recent outbreaks have served as wake-up calls to many experts as a further indicator of the need for a melding of the two disciplines. Two simultaneous outbreaks of West Nile virus in the United States in 1999 brought the need for communication to the forefront of public health.
One outbreak of West Nile virus was in humans and the other in crows; it was the efforts of an astute veterinarian at the Bronx Zoo in New York City who was able to tie it together, Laura H. Kahn, PhD, a researcher in the Program on Science and Global Security at Princeton University, said at the meeting. Since then, it has been recognized that human and animal health are inextricably linked.
The link between animal and human health is not novel. Kahn described the history of the convergence of human and animal diseases as illustrious, wrought with opposition and bold experimentation.
Kahn discussed one of the earliest examples of research of the convergence of human and animal diseases: the controversial research of Edward Jenner, MD (1749-1843), known for his experiments with variolation. As a physician, Jenner learned of patients who were immune to smallpox after acquiring cow pox. Jenner injected smallpox pus into a scratch on the skin of a young boy, who became sick but did not die. The experiment was then repeated with other people. When Jenner wrote to the Royal Academy with his findings, it not only rejected his hypothesis but threatened his career. He remained undaunted and self-published his work amid great opposition.
Veterinary and human health
Veterinary medicine has its roots in human health. Culling of livestock as a way to control rinderpest, a lethal viral disease in cattle, began in the 18th century as a way to protect the human food supply. The first school of veterinary medicine was established in order to ensure healthy animals as food for humans.
Louis Pasteur studied chicken cholera in 1880, and after injecting chickens with weakened forms of the disease, he discovered chickens developed immunity to cholera. His concepts were later expanded to anthrax and rabies. Many scientists followed his hypothesis, building the framework for advancements in understanding yellow fever and equine encephalitis.
In a joint effort in 1967, an expert committee from the Food and Agriculture Organization and WHO recognized more than 150 zoonotic diseases of concern.
By 2000, more than 200 diseases occurring in humans and animals were known to be transmitted mutually, which led to the recognition of a more than 30% increase in zoonotic diseases in the last third of the 20th century.
West Nile virus triggered the recognition that animal health affects human health, and of course, the knowledge that most of the agents of bioterrorism are zoonotic, Kahn said.
A multitude of human behaviors worldwide contribute to the emergence of zoonotic disease, including population pressures, deforestation, intensive agriculture and the consumption of bushmeat.
Used tires that are imported and dumped are mosquito incubators; air travel and the global trade of exotic animals are also contributors, Kahn said. The magnitude of the challenge is considerable; many of these newly identified zoonotic agents are RNA viruses few scientists have recognized, and we can expect more to emerge as our activities continue.
It is estimated that the oceans alone contain 4x1030 viruses, Kahn said, which is larger than the number of stars in the observable universe. – by Kirsten H. Ellis
For more information:
- Kahn LH. One Medicine: A brief historical overview. #107. Presented at: The 56th Annual Meeting of the American Society of Tropical Medicine and Hygiene; Nov. 4-8, 2007; Philadelphia.