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Two men talking with a background of trees and grass

Will Hueston, (left) Director of the Center for Animal Health and Food Safety, and colleague Jeffrey Reneau discuss the importance of the animal-human disease connection

The animal connection

U experts watch the world's animal health as a critical barometer of human health

by Richard Broderick

Aug. 31, 2006

Nothing concentrates the mind, Samuel Johnson once observed, like the prospect of being hanged in the morning.

While we don't face the prospect of mass execution, we do confront a public health threat so potentially catastrophic that it has refocused our collective minds on what was, until recently, a medical backwater--zoonotic infectious diseases. In other words, diseases humans can catch from animals.

"What we tend to lose sight of is that 61 percent of all infectious agents known to cause diseases in humans are zoonotic," explains Marguerite Pappaioanou, an infectious disease expert in the School of Public Health. "Flu, TB, AIDS, plague, anthrax, Ebola, rabies, ringworm, roundworm, food-borne pathogens--all are zoonotic diseases. If you turn to emerging infectious diseases, 75 percent are zoonotic. And, if you look at pathogens that pose a bioterrorist threat, 80 percent are zoonotic."

Over the past two decades, the notoriety attached to HIV/AIDS, Lyme disease, West Nile Virus, BSE (bovine spongiform encephalopathy or Mad Cow Disease), and potentially weaponized anthrax, has heightened awareness of the intimate connection between animal and human health. But, it is the prospect of a global pandemic triggered by the potential mutation of a deadly strain of avian influenza that has government and health officials taking a much more aggressive approach to zoonotic disease.

"If we take the lessons we have learned and apply them to the avian flu, they tell us we have to be open and honest and we must communicate with all our publics, from first responders to public officials to the general public." --Will Hueston

Indeed, Pappaioanou herself, along with colleagues from the College of Veterinary Medicine and the Medical School, is spearheading a groundbreaking USAID-funded program to initiate comprehensive monitoring of flu in Tanzania. This is where the potential introduction of the virus is possible via 15 million migratory birds who visit Tanzania annually, and by people (and their poultry) from eight neighboring countries who cross the border regularly.

There is, without question, cause for concern. In 1918 and 1919, the Spanish Flu, a strain of avian flu, swept the globe, killing an estimated 50 to 200 million people worldwide and at least 500,000 in this country. The scale of the outbreak overwhelmed America's public health system; today, even given the medical advances of the past 88 years, a similar flu pandemic could do the same thing.

"If you look at the causes of mortality around the world, you'll see that heart disease and cancer kill more people on this planet than anything else," says John Finnegan, dean of the School of Public Health. "Zoonotic diseases do not come close to killing as many people as chronic diseases, but they do have the capability of creating huge surges of illness that not only threaten to overwhelm our health system, but also disrupt the global economy."

The growing recognition of this threat, Finnegan explains, has reinvigorated the ties at the University between veterinary medicine and public health, most notably through the establishment of one of the country's first D.V.M.-M.P.H.(Doctor of Veterinary Medicine-Master of Public Health) dual-degree programs. For the 110 or so students currently enrolled in the program (including students from 10 other veterinary medicine schools around the country) the opportunity offered by the AHC is unique.

"The advantage here is that it's rare to find a school of public health and a college of veterinary medicine located in the same institution," Finnegan says.

The dual vet-med/public health degree, like the Public Health Certificate in Food Safety and Biosecurity also offered by the School of Public Health, is just part of the AHC's broader multi-disciplinary and even multi-agency response to zoonotic disease.

Marguerite Pappaioanou in front of a shelf of books
Marguerite Pappaioanou, of the School of Public Health, is heading up a groundbreaking program to monitor influenza in Tanzania, where it may be introduced via migratory or domestic birds.

That response includes programs like the Center for Infectious Disease Research and Policy, or CIDRAP (whose director, Michael Osterholm continually points out that in a globalized world we are only a plane ride away from a pandemic); the Center for Animal Health and Food Safety, directed by William Hueston, who holds a joint appointment in the College of Veterinary Medicine and the School of Public Health; the National Center for Food Protection and Defense, a Department of Homeland Security initiative in which the University is a major partner; and Pappaioanou's Tanzanian program.

In addition, other University faculty work with officials from both the federal and state departments of health and agriculture, the Department of Natural Resources, and the Minnesota Board of Animal Health to monitor, diagnose, and prevent the spread of zoonotic infections in wild and domestic animals. Today, for example, Minnesota-bred turkeys and chickens are regularly checked for avian flu at the University's Poultry Testing Center in Willmar.

"When we ask ourselves why we are seeing the emergence of so many zoonotic diseases, we can see there are a number of factors," explains Jeffrey Bender, who teaches classes on zoonotic disease both in the College of Veterinary Medicine and the School of Public Health. "There are ecological factors and changes, like deforestation and also reforestation (Lyme disease, for example, emerged as a result of the reforestation of certain areas of the northeastern United States, which made it an ideal spawning ground for the mice and deer that spread the infection). There's the trade in exotic animals, global travel, and even changes in modern agricultural practices such as the use of meat and bonemeal as a cheap source of food for cattle, which can cause BSE or Mad Cow Disease.

"Clearly one of the things we have learned in the past five to 10 years is the need for a multidisciplinary approach for (zoonotic) disease detection, prevention, and treatment."

Too little, or the wrong kind of information, can induce public confusion, and perhaps even panic.

While detection, prevention, and treatment of zoonotic diseases are critical, an equally important task facing health officials is effective communication of the risk. Too little, or the wrong kind of information, can induce public confusion, and perhaps even panic. That's why every month Hueston holds discussions with communicators from the AHC and state agencies about animal and health issues. In March, he conducted a risk communication program for the deans of veterinary and public health schools around the country. He and colleagues also teach classes in risk communication at the AHC's annual Public Health Institute.

"The Centers for Disease Control has coined the phrase, 'Be first, be right, be credible,' " he says. If knowledgeable individuals, university experts, and government officials are ready to step into the information void caused by a crisis, they can have a huge effect on public reaction, Hueston explains.

"Minnesota far and away has the strongest commitment to collaboration and partnership of any school where I've worked," Hueston says. "Building transdisciplinary teams is critical for dealing with these growing threats. No single initiative is going to answer the myriad of infectious disease challenges we face."