Veterinary medicine has a long and impressive history of leadership in certain areas of public health. Several animal diseases caused by infectious agents that also cause serious illness in humans have been eradicated or controlled for the benefit of the health of human beings and animals. Foremost among these are tuberculosis and brucellosis.
TB testing began in Canada in 1897; the first comprehensive testing involving 500 million cattle was carried out in 1961 and TB-free status was recognized by the United States in 1997. Elimination was based on test and slaughter programs, combined with vaccination in the case of brucellosis. Canadian cattle were declared brucellosis free in 1985 and the number of cases of this disease in humans has dwindled to a few per year.
Although there are reservoirs of TB and brucellosis in wildlife in parts of Manitoba and Alberta, both diseases are no longer a concern in cattle or in human health in this country. Surveillance continues to be maintained by the Canadian Food Inspection Agency (CFIA) to keep the national cattle herd free of these diseases.
Meat inspection has long been another area in which public veterinary practice has contributed to safeguarding human health. The recent outbreaks of listeriosis associated with cheese in Quebec and meat in Ontario are reminders of the extent to which failures in food safety can have disastrous consequences. Vaccination of wildlife against rabies and surveillance programs for infections such as bovine spongiform encephalopathy (BSE) and avian influenza are other examples of public veterinary practice at work.
We are now embarking on a new era for veterinary public health, based on renewed recognition of the “one medicine” or “one health” concept. This concept was espoused long ago by leaders in the field such as Calvin Schwabe at University of California Davis and James Steele, former Assistant Surgeon General, presently at the University of Texas Health Science Center at Houston. Schwabe founded the discipline of Veterinary Epidemiology and Preventive Medicine and supervised the education of many of the leading veterinary epidemiologists (including Wayne Martin at Guelph).
Steele established veterinary public health as a section within the Center for Disease Control and Prevention (CDC) in Atlanta. Today there is much broader awareness that animal infections and diseases play a major role in human infectious disease. The importance of the animal-human link in infectious disease has been reinforced by the emergence in North America of human diseases such as those caused by West Nile virus, O157:H7 E. coli, the SARS coronavirus, and the threat of avian-derived influenza, all of which have animal reservoirs. A long neglected area, companion animals as sources of zoonotic bacterial pathogens, is now being investigated and Canada’s Scott Weese is an international leader in this field.
The response to the heightened concern about zoonotic diseases has included closer interaction between the veterinary and medical professions and expansion of the involvement of veterinary epidemiologists in public health in organizations such as the CDC in the United States and the Public Health Agency of Canada (PHAC). Recently, Dr. Robert Clarke, a veterinarian with a record of outstanding leadership roles in Agriculture and Agri-Foods Canada, Health Canada, and the CFIA, was appointed Assistant Deputy Minister, PHAC.
In the United States, Dr. Lonnie King, former dean of veterinary medicine at Michigan State University, was appointed director of the newly formed National Center for Zoonotic, Vector-Borne, and Enteric Diseases (ZVED) at the CDC. In veterinary schools new MPH programs and public health research centers are being established and changes are being made in the curricula to better prepare veterinarians to contribute to public health, whether they join the government service or become private practitioners.
The role of wildlife as a reservoir of not only well-established zoonoses such as rabies but also of more recently emerging zoonoses such as West Nile virus infection and SARS is being recognized, and the concept of ecosystem health, which has been slow to gain recognition, is now receiving greater prominence. Improved public health training and re-orientation of veterinary graduates to use their knowledge and unique perspective in the service of not only animal but also human health is a key element of reform in the DVM program in many veterinary schools.
Students are now being encouraged to ask questions about human health, when they are relevant in relation to a health problem in an animal, and to advise owners to seek medical attention when that is warranted. All 5 schools in Canada make epidemiology and public health major areas of focus in the DVM and post-DVM programs and in research. Collaboration with a medical school and/or PHAC is a common feature of these activities.
An expanded role for veterinarians in public health represents both enhanced service to society and increased responsibility. There is every indication that our graduates are being well prepared to excel in these activities in both public and private practice.