One Health has been defined as "the collaborative effort of multiple disciplines — working locally, nationally, and globally — to attain optimal health for people, animals and the environment".
One Health is a new phrase, but the concept extends back to ancient times. The recognition that environmental factors can impact human health can be traced as far back as to the Greek physician Hippocrates (c. 460 BCE – c. 370 BCE) in his text "On Airs, Waters, and Places". He promoted the concept that public health depended on a clean environment.
The Italian physician Giovanni Maria Lancisi (1654–1720) was a pioneering epidemiologist, physician, and veterinarian, with a fascination in the role the physical environment played in the spread of disease in humans and animals. Lancisi may have been the first to advocate the use of mosquito nets for prevention of malaria in humans but was also a pioneer in the control of rinderpest in cattle. The idea that human, animal and environmental healths are linked was further revived during the French Revolution by Drs Louis-René Villerme (1782–1863) and Alexandre Parent-Duchâtelet(fr) (1790–1835) who developed the specialty of public hygiene.
In the late 19th century, German physician and pathologist Rudolf Virchow (1821–1902) coined the term "zoonosis", and said "...between animal and human medicine there are no dividing lines – nor should there be". Canadian physician Sir William Osler (1849–1919) traveled to Germany to study with Virchow. He returned to Canada and held joint faculty appointments at the McGill University Medical School and the Montreal Veterinary College. Osler was active as a clinical pathologist and internist at the Montreal General Hospital, but was also active in the promotion of veterinary health, and helped investigate a swine typhoid outbreak near Quebec City in 1878; he subsequently co-authored a monograph on parasites in Montreal's pork supply with A. W. Clement, a veterinary student at Montreal Veterinary College.
In 1947, James H. Steele, DVM (Doctor of veterinary medicine), furthered the concept in the U.S. by establishing the field of veterinary public health at the CDC. The phrase "One Medicine" was developed and promoted by Calvin W. Schwabe (1927–2006), a veterinary epidemiologist and parasitologist in his textbook "Veterinary Medicine and Human Health".
Emerging infectious diseases
Many emerging health issues are linked to increasing contact between humans and wildlife, intensification and integration of food production, and the expansion of international travel. As the number of new infectious diseases emerged in the 20th century, scientists began to recognize the challenges societies face regarding these threats that largely come from animals. Of the 1,415 microbes that are known to infect humans, 61 percent come from animals. For example, rodents transmit plague and typhus to humans, and domestic livestock are the original source of crowd diseases such as measles, mumps, and pertussis. One important exception is Mycobacteria tuberculosis. Genetic evidence suggests that Mycobacteria tuberculosis originated in human populations and spread to animals. Chimpanzees were a reservoir host for the human immunodeficiency virus. Global trade of wildlife exacerbates the problem of disease emergence.
The 1999 West Nile virus outbreak in New York City highlighted the links between human and animal health. In this outbreak, wild crows began dying about a month or so before people began getting sick. The simultaneous outbreaks were not recognized as caused by the same entity until Dr. Tracey McNamara, an astute veterinarian at the Bronx Zoo, tied them together when her exotic birds began getting sick. After it was recognized that the outbreaks were caused by West Nile virus, a new entity in the Western Hemisphere, the CDC established the National Center for Zoonotic, Vector-Borne, and Enteric Diseases, now the National Center for Emerging and Zoonotic Infectious Diseases.
In 2004, the Wildlife Conservation Society (WCS) convened a group of health experts at Rockefeller University in New York and developed the phrase "One World - One Health" in order to promote the recognition of the impact of land use and wildlife health on human health. William B. Karesh, one of the leaders of the WCS effort, wrote articles in Foreign Affairs about the health links between humans, animals, and the environment.
The avian influenza (HPAI H5N1) epidemic that began in Hong Kong in 1997 forced the global community to recognize that animal health and human health are linked. The 1997 outbreak affected 18 people, killed 6, and provoked the culling of 1.5 million birds. The HPAI H5N1 virus resurfaced in isolated outbreaks between 1998–2003, but a widespread outbreak occurred in mid-2003 in South Korea. Delays in international reporting and weak response measures contributed to the spread of the virus across Southeast Asia. In recognition of the global threat that avian influenza (HPAI H5N1) and other emerging zoonotic diseases posed, the Food and Agriculture Organization (FAO), World Health Organization (WHO), and World Organization for Animal Health (OIE) developed a strategic framework, a tripartite agreement, to work more closely together to address the animal-human-ecosystem interface.
Animals suffer from many of the same chronic diseases such as heart disease, cancer, diabetes, asthma, and arthritis as humans. Sometimes a disease entity is recognized in animals long before it is recognized in humans. For example, fear-induced heart failure was described in wildlife about thirty years before it was recognized in humans. Comparative medicine is the study of disease processes across species and is based on the study of naturally occurring diseases of animals that also afflict humans. The concept of comparative medicine is very old. The ancient Greeks understood that dissecting and studying animals could yield important clues to understanding human diseases. From Galen to William Harvey, comparative anatomical and physiological studies have been responsible for significant advances in medicine; Frederick Banting and Charles Best discovered insulin through such work.
The musculoskeletal system is particularly well-suited to comparative medicine studies since acute and chronic disorders of bones and joints have the same counterparts in humans and animals. Information gained from one species can be directly translated to another, thereby advancing the diagnosis and treatment of musculoskeletal disorders. Since the early 1930s, comparative orthopaedic research has incorporated the One Health concept. Otto Stader, a small animal veterinarian, used a comparative medicine approach and developed the first form of external skeletal fixation, the Stader splint, as a way to stabilize fractures in dogs. During World War II, Navy surgeons improved the treatment of fractures in sailors by incorporating Stader's advances. During the 1940s and 50's, Jacques Jenny, a veterinary surgeon, performed one of the first intra-medullary pinning procedures in animals and significantly advanced fracture repair strategies in horses and humans. In 1966, Sten-Erik Olsson VMD, MD and John L. Marshall DVM, MD, both of whom had medical and veterinary medical degrees, founded the first laboratory dedicated to comparative orthopaedic research at the Hospital for Special Surgery in New York. In the 21st century, comparative orthopaedic laboratories are located throughout the world and use both a comparative and translational research approach in an effort to improve diagnostic capabilities, enhance preventive and therapeutic strategies, and advance the understanding of disease mechanisms. Advances in fracture fixation, total joint replacement, and cartilage repair are a few examples of how knowledge flows in both directions, to benefit both human and animal health.
Urbanization, globalization, climate shift, and terrorism have brought the need for a more diverse public health workforce to the forefront of public planning. Changes in land use, creation and operation of large terrestrial and marine food production units, and microbial and chemical pollution of land and water sources have created new threats to the health of both animals and humans. For example, deforestation for agriculture can lead to the emergence of zoonotic diseases. Medical doctors are turning to environmental health scientists and practitioners to help them track disease outbreaks to the source, prevent chronic disease caused by chemical exposure, and create healthier living environments. Veterinarians are also turning to environmental health scientists and practitioners to prevent and control outbreaks and public health emergencies. One Health is the perfect unifying concept to bring together human health care practitioners, veterinarians, and public health professionals under the umbrella of environmental health. By strengthening epidemiologic and laboratory investigations that assess the role of environmental influences, this partnership can help to develop and apply sustainable and effective community health interventions.
The One Health Commission: in 2007, Dr. Roger Mahr, the President of the American Veterinary Medical Association (AVMA), met with Dr. Ronald Davis, the President of the American Medical Association, to discuss bringing the animal and human medical communities together. Dr. Davis suggested that the best way for the AMA to get involved in such an endeavor would be to pass a formal "One Health" resolution. In June 2007, the AMA unanimously adopted this resolution. The AVMA established a One Health Initiative Task Force and passed a One Health resolution analogous to the AMA's resolution in July 2008. The One Health Task Force eventually became the One Health Commission headed by Dr. Roger Mahr. It is headquartered at Iowa State University.
The One Health Initiative is separate from the One Health Commission. The One Health Initiative website has been serving as a global repository for all news and information pertaining to One Health. Organizations promoting this movement are listed on this website and include the American Medical Association, American Veterinary Medical Association, the American Society of Tropical Medicine and Hygiene, The American Association of Public Health Physicians, the Centers for Disease Control and Prevention (CDC), the United States Department of Agriculture (USDA), and the U.S. National Environmental Health Association (NEHA). Additionally, more than 700 prominent scientists, physicians and veterinarians worldwide have endorsed the initiative. Additional history about the One Health Initiative is available at Horizon International, a non-profit organization based at Yale University, working to find and advance solutions to inter-related concerns of global health, the environment, and poverty.
In the USA, the CDC has a One Health website that lists meetings related to One Health. The 1st International One Health Congress met February 14–16, 2011 in Melbourne, Australia. The 2nd International One Health Congress met January 29-February 2, 2013 in Bangkok, Thailand.
The World Bank is investigating how to demonstrate the cost effectiveness of a One Health approach to global health. In June 2012, the World Bank published the economic benefits of One Health.
The importance of One Health is promoted by scientists in many countries and supported by prominent organizations including the World Health Organization, Food and Agriculture Organization, World Organization for Animal Health, The International Federation for Animal Health, Global Alliance for Rabies Control, New Zealand Centre for Conservation Medicine (NZCCM), Hubnet in Asia the One Health Global Network,  the University of California One Health Center, and the Infection Ecology and Epidemiology Network, Uppsala, Sweden.
- The American Veterinary Medical Association. One Health Initiative Task Force. "One Health: A New Professional Imperative". July 15, 2008. https://www.avma.org/KB/Resources/Reports/Documents/onehealth_final.pdf. Accessed September 1, 2011.
- The Internet Classics Archive. Hippocrates. "On Airs, Waters, and Places". 400 BCE. Translated by Francis Adams. http://classics.mit.edu/Hippocrates/airwatpl.html. Accessed September 1, 2011.
- Drake D. A practical treatise on the history, prevention, and treatment of epidemic cholera, designed both for the profession and the people. Cincinnati, Corey and Fairbank, 1832.
- A. F. LaBerge. "Mission and Method. The Early Nineteenth-Century French Public Health Movement." Cambridge, England: Cambridge University Press, 1992.
- Kahn LH, Kaplan B, Steele JH. "Confronting zoonoses through closer collaboration between medicine and veterinary medicine (as 'one medicine'). Veterinaria Italiana 2007; 43(1): 5-19. http://www.onehealthinitiative.com/publications/01%20Kahn%20et%20al%20%205-19%208Mar07.pdf. Accessed September 1, 2011.
- Murphy, DA. Osler, now a veterinarian! Can Med Assoc J 1960 July 2; 83(1): 32–35.
- Osler W., Clement A. W. An investigation into the parasites in the pork supply of Montreal, 1883. Gazette Printing Company, Montreal.
- Waddy J. "Father of Veterinary Public Health Profiled in New Book." The University of Texas Health Sciences Center. August 14, 2009. http://www.texasmedicalcenter.org/root/en/TMCServices/News/2009/08-14/Father+of+Veterinary+Public+Health+Profiled+in+New+Book.htm. Accessed September 1, 2011.
- Kass PH, McCapes RH, Pritchard WR. "In Memoriam. Calvin W. Schwabe. Professor Emeritus of Veterinary Epidemiology. Davis. 1927-2006. http://www.universityofcalifornia.edu/senate/inmemoriam/calvinwschwabe.htm. Accessed September 1, 2011.
- The World Health Organization. The world health report 1999--making a difference. http://www.who.int/whr/1999/en/index.html. accessed September 1, 2011
- Institute of Medicine. "Emerging Infections — Microbial Threats to Health in the United States". January 1, 1992. National Academies Press. http://www.iom.edu/Reports/1992/Emerging-Infections-Microbial-Threats-to-Health-in-the-United-States.aspx. Accessed September 1, 2011.
- Jones K. E., Patel N. G., Levy M. A., et al. "Global trends in emerging infectious diseases". Nature. February 21, 2008. 451: 990-993. http://www.nature.com/nature/journal/v451/n7181/abs/nature06536.html. Accessed September 1, 2011.
- Taylor LH, Latham SM, Woolhouse ME. "Risk Factors for Human Disease Emergence." Philos Trans R Soc Lond B Biol Sci July 29, 2001. 356(1411): 983-989. Taylor LH, Latham SM, Woolhouse ME (July 2001). "Risk factors for human disease emergence". Philos. Trans. R. Soc. Lond., B, Biol. Sci. 356 (1411): 983–9. doi:10.1098/rstb.2001.0888. PMC 1088493. PMID 11516376. Accessed September 1, 2011.
- Wolfe ND, Dunavan CP, Diamond J. "Origins of major human infectious diseases." Nature May 17, 2007. 447: 279-283. http://www.gvfi.org/docs/Publications/4.%20Nature.pdf. Accessed September 1, 2011.
- Wirth T, Hidebrand F, Allix-Beguec C. et al. Origin, Spread and Demography of the Mycobacterium tuberculosis Complex. PLOS Pathogens 4(9): e1000160. doi: 10.1371/journal. ppat. 1000160. http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1000160. Accessed April 28, 2013.
- Keele B. F., van Heuverswyn F., Li Y., et al. "Chimpanzee Reservoirs of Pandemic and Nonpandemic HIV-1". Science July 18, 2006. 313(5786): 523-526. http://www.sciencemag.org/content/313/5786/523. Accessed September 1, 2011.
- Karesh W. B., Cook R. A., Bennett E. L., et al. "Wildlife Trade and Global Disease Emergence". Emerging Infectious Diseases July 2005. 11(7): 1000-1002. http://www.cdc.gov/ncidod/eid/vol11no07/05-0194.htm. Accessed September 1, 2011.
- U.S. General Accounting Office (GAO). "West Nile Virus Outbreak — Lessons for Public Health Preparedness". September 2000. GAO/HEHS-00-180. http://www.gao.gov/new.items/he00180.pdf. Accessed September 1, 2011.
- Drexler, M. "Secret Agents — The menace of emerging infections" 2002 Joseph Henry Press. http://books.google.com/books?id=nnRuEoynzE4C&printsec=frontcover&dq=Madeline+Drexler+Secret+Agents&source=bl&ots=0zjYAWOT8c&sig=HPvLemUlPJJ9O8Rj-ZzXVYI95ic&hl=en&ei=7TiCTb3tKOK30QGd7rTOCA&sa=X&oi=book_result&ct=result&resnum=3&sqi=2&ved=0CC0Q6AEwAg#v=onepage&q&f=false
- Centers for Disease Control and Prevention National Center for Emerging and Zoonotic Infectious Diseases. http://www.cdc.gov/ncezid/. Accessed September 1, 2011.
- Wildlife Conservation Society. "One World - One Health". http://www.wcs.org/conservation-challenges/wildlife-health/wildlife-humans-and-livestock/one-world-one-health.aspx. Accessed September 1, 2011.
- Karesh W. B., Cook R. A. "The Human-Animal Link". Foreign Affairs July/August 2005. http://www.foreignaffairs.com/articles/60821/william-b-karesh-and-robert-a-cook/the-human-animal-link. Accessed September 1, 2011.
- Karesh W. B. “Where the Wild Things Are — The Link Between the Health of Humans, Animals, and the Environment”. Foreign Affairs May 8, 2009. http://www.foreignaffairs.com/articles/65088/william-b-karesh/where-the-wild-things-are. Accessed September 1, 2011.
- National Research Council. "Animal Health at the Crossroads — Preventing, Detecting, and Diagnosing Animal DIseases". National Academies Press. 2005. http://www.nap.edu/catalog.php?record_id=11365. Accessed September 1, 2011.
- Institute of Medicine. "Sustaining Global Surveillance and Response to Emerging Zoonotic Diseases". National Academies Press. September 22, 2009. http://www.iom.edu/Reports/2009/ZoonoticDisease.aspx. Accessed September 1, 2011.
- The FAO-OIE-WHO Collaboration. A Tripartite Concept Note. April 2010. http://web.oie.int/downld/FINAL_CONCEPT_NOTE_Hanoi.pdf. Accessed September 1, 2011.
- JAVMA News. One Health Wonders. October 1, 2008. https://www.avma.org/News/JAVMANews/Pages/081001h.aspx. Accessed December 4, 2012.
- Olsson S-E. Comparative Orthopaedics. Clin Orthop Related Res 1969; 62: 3-5.
- Lyons AS, Petrucelli RJ. "Medicine: An Illustrated History." 1978. Abradale Press, New York.
- Cook JL, Arnoczky SP. "The One Health Concept in Comparative Orthopaedics." One Health Newsletter Florida Department of Health. Summer 2009; vol. 2, issue 3. http://www.doh.state.fl.us/environment/medicine/One_Health/OHNLSummer2009.pdf. Accessed September 2, 2011.
- Pappaioanou M. "Veterinary medicine protecting and promoting the public's health and well-being." Preventive Veterinary Medicine. 2004; 62: 153-163. http://www.ncbi.nlm.nih.gov/pubmed/15041202. Accessed September 1, 2011.
- Zinsstag J., Schelling E., Wyss K., et al. "Potential of cooperation between human and animal health to strengthen health systems". The Lancet. 2005; 336: 1242-1245. http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)67731-8/fulltext. Accessed September 1, 2011.
- Kahn LH. "Deforestation and Emerging Diseases. Bulletin of the Atomic Scientists. Feb. 15, 2011. http://www.thebulletin.org/web-edition/columnists/laura-h-kahn/deforestation-and-emerging-diseases
- JAVMA News. "AMA adopts one-health policy — Physicians' association supports ties with AVMA". Journal of the American Veterinary Medical Association (JAVMA). August 1, 2007. https://www.avma.org/News/JAVMANews/Pages/070801b.aspx. Accessed September 1, 2011.
- Kahn L. H. "‘One Medicine — One Health’ interview with Ronald M. Davis, MD, President of the American Medical Association, 14 May 2008". Veterinaria Italiana. 2009; 45(1): 19-21. http://www.izs.it/vet_italiana/2009/45_1/19.pdf. Accessed September 1, 2011.
- JAVMA News. "One-health wonders". January 15, 2009. https://www.avma.org/News/JAVMANews/Pages/090115d.aspx. Accessed September 1, 2011.
- The One Health Commission home page. http://www.onehealthcommission.org/objective.html. Accessed September 1, 2011.
- The One Health Commission news. "Global comprehensive health organization, One Health Commission locates to ISU." http://www.onehealthcommission.org/news/ISU-OHCPressRelease.pdf[dead link]. Accessed September 1, 2011.
- The American Association of Public Health Physicians website. http://www.aaphp.org/OneHealth. Accessed April 28, 2013.
- The National Environmental Health Association October 2008 position paper on One Health. http://www.neha.org/pdf/position_one_world.pdf. Accessed April 28, 2013.
- One Health Initiative website. http://www.onehealthinitiative.com. Accessed September 1, 2011.
- Horizon International website http://www.solutions-site.org/node/875. Accessed April 28, 2013.
- European Union. "One Health: Addressing health risks at the interface between animals, humans, and their environments." http://eeas.europa.eu/health/pandemic_readiness/index_en.htm. Accessed April 28, 2013.
- Centers for Disease Control and Prevention. One Health Related Meetings. One Health. http://www.cdc.gov/onehealth/meetings.html. Accessed September 1, 2011.
- First International One Health Congress. Global Health Vet website http://globalhealthvet.com/2011/02/20/one-health-congress-report-14-16-feb-2011-melbourne-australia/. Accessed April 28, 2013.
- One Health Global Network website. http://www.onehealthglobal.net/?p=1369
- First One Health Conference in Africa. http://www.sacids.org/kms/frontend/?m=101. Accessed September 1, 2011.
- The World Bank. "People, Pathogens and Our Planet. Volume 1: Towards a One Health Approach for Controlling Zoonotic Diseases." Report no. 50833-GLB. 2010. http://siteresources.worldbank.org/INTARD/Resources/PPP_Web.pdf. Accessed September 1, 2010.
- The World Bank. "People, Pathogens, and Our Planet. Volume 2: The Economics of One Health." Report no. 69145-GLB. http://www-wds.worldbank.org/external/default/WDSContentServer/WDSP/IB/2012/06/12/000333038_20120612014653/Rendered/PDF/691450ESW0whit0D0ESW120PPPvol120web.pdf. Accessed April 28, 2013.
- World Organization for Animal Health. One World, One Health. http://www.oie.int/en/for-the-media/editorials/detail/article/one-world-one-health/. Accessed September 1, 2011.
- International Federation for Animal Health. http://www.ifahsec.org/our-industry/oneworldonehealth/. Accessed April 28, 2013.
- Global Alliance for Rabies Control. People and Animals. http://www.rabiescontrol.net/what-we-do/save-lives.html. Accessed September 1, 2011.
- New Zealand Centre for Conservation Medicine. http://www.conservationmedicine.co.nz/main-conservation-medicine.aspx. Accessed September 1, 2011.
- Hubnet website. http://www.hubnet.asia/. Accessed April 28, 2013.
- The One Health Global Network website http://www.onehealthglobal.net. Accessed May 13, 2013.
- University of California Global Health Institute. One Health: Water, Animals, Food and Society. http://www.ucghi.universityofcalifornia.edu/coes/one-health/index.aspx. Accessed September 1, 2011.
- Infection, Ecology, and Epidemiology. The One Health Journal. http://www.infectionecologyandepidemiology.net/index.php/iee/index. Accessed April 28, 2013.
Rabinowitz P. M. and Conti L. A. Human-Animal Medicine — Clinical Approaches to Zoonoses, Toxicants and Other Shared Health Risks. Saunders Elsevier. 2010. ISBN 10-1416068376. Reviewed by Brown C. Human-animal medicine: clinical approaches to zoonoses, toxicants and other shared health risks [book review]. Emerg Infect Dis [serial on the Internet]. 2010 Jun [date cited]. http://wwwnc.cdc.gov/eid/article/16/6/10-0367.htm. Accessed April 28, 2013.
Natterson-Horowitz B and Bowers K. Zoobiquity. What Animals Can Teach Us About Health and the Science of Healing. 2012. Knopf, New York. http://www.goodreads.com/book/show/13147888-zoobiquity. Accessed May 16, 2013.
Quammen D. Spillover. Animal Infections & the Next Human Pandemic. 2012. W.W. Norton & Co. http://www.goodreads.com/book/show/13637215-spillover. Accessed May 16, 2013.