Veterinarians and physicians: Working together for one medicine

About 60% of all human pathogens are zoonotic, transmissible between animals and people. Even more striking, approximately 75% of recently emerging infectious diseases affecting humans are of animal origin.

These Centers for Disease Control and Prevention statistics underscore just how important a new partnership being forged between the worlds of human and animal medicine is to public health. The American Medical Association and American Veterinary Medical Assn. are taking the lead.

Last September, Roger Mahr, DVM, newly elected as AVMA president, announced his intent to launch an effort to unite human and veterinary medicine to improve animal and public health. Then in June, the AMA voted at its Annual Meeting to increase collaboration with the veterinary community to better recognize, monitor and treat zoonotic diseases, and more broadly collaborate in medical education and biomedical research. Just a month later, AMA President Ronald M. Davis, MD, offered his support to Dr. Mahr's project, dubbed the One Health Initiative.

The One Health concept is not new. Dr. Mahr pointed out in a 2006 address that physician Sir William Osler, founder of the modern medical teaching concept, wrote in the 1800s that "veterinary medicine and human medicine complement each other and should be considered as one medicine." In the 1960s, veterinary epidemiologist Calvin Schwabe, DVM, MPH, ScD, took up the cause using the phrase "one medicine." But the concept didn't catch on in either medical community, despite the prevalence of diseases shared by humans and animals.

Zoonotic disease has an exotic ring to it. It brings to mind rare, remote and deadly ailments. "Ebola mystique" is the term Frederick Murphy, DVM, PhD, professor of virology in the University of California, Davis, School of Veterinary Medicine, has used to describe this perception.

In reality, zoonotic disease is usually more familiar than it sounds. It could strike in the backyard, in the case of rabies, or at the dinner table, in the form of salmonella.

Ironically, West Nile disease's emergence in 1999 and rapid spread to most U.S. states helped give the One Health concept traction. The spread of the virus from Africa and Asia to the U.S. brought the need for collaboration between the human and veterinary medical communities home, literally.

West Nile showed how global societal changes have increased the stakes by making the spread of zoonotic disease easier than it was in Dr. Osler's era and even Dr. Schwabe's day. The growth of global travel and trade indeed do mean that existing and emerging conditions in far-away places can affect human health here. Poor sanitation and the proximity of animals and humans in an Asian village have the potential to give rise to pandemic influenza or a version of avian flu that is more easily spread by human-to-human contact.

Meanwhile, more than 38,000 animals are transported into the U.S. each day, Dr. Mahr noted. The nation imports produce from around the world. This adds the risk of zoonotic foodborne illness from other countries to the existing home-grown threat of such ailments. Each year, foodborne pathogens cause an estimated 76 million illnesses, 325,000 hospitalizations and 5,000 deaths in the U.S, the CDC says.

Trends in livestock farming here and elsewhere also can affect human health -- from the feeding of bovine offal to cattle, resulting in the emergence of variant Creutzfeldt-Jakob disease, to the worry that widespread use of antibiotics to increase animal productivity is leading to drug resistance among bacteria that infect humans.

The threat of bioterrorism poses new danger. The CDC is studying the potential that terrorists might weaponize such zoonotic diseases as anthrax, tularemia or plague.

The budding collaboration between the human and animal medical communities means that physicians and veterinarians will be better prepared for and better able to identify and respond to zoonotic disease outbreaks, whatever their source.

As the preamble to the resolution that became the new AMA policy states, "The challenges of the 21st century demand that these two professions work together."