One Planet, One Health
As animal and human welfare are increasingly intertwined, veterinarians are playing a key role in keeping us all thriving.
Kristine Smith, V02, is garbed in face mask and gloves, taking blood samples from white swans. It's not unusual work for a veterinarian, except that Smith isn't in a clinic—she's by an isolated lake in northern Mongolia. And it's not the only place she's done this kind of work. In the last several years, she's been in locales as far-flung as South Africa, Kazakhstan and Cambodia.
Her goal is simple, even if achieving it isn't: to understand the transmission of avian influenza by wild birds. An infectious disease that affects millions of birds, it has killed hundreds of humans, too. Decoding the disease before it mutates into a form easily transmissible among humans is critical to controlling an outbreak, should it cross over into humans and become a pandemic.
It might not seem like typical work for a graduate of a veterinary school, but as the world shrinks, veterinarians are increasingly becoming prominent players in the global health system. In fact, there's a name that sums it up nicely: One Health.
"The concept has been around a long time. There is no dividing line between human and veterinary medicine," says Deborah Kochevar, dean of the Cummings School of Veterinary Medicine. "It should be viewed as one medicine, one health."
"There's a recent strong push in the veterinary profession, and a growing movement in the human medical profession, to join forces in combating diseases that we share with animals," says George Saperstein, chair of the school's department of environmental and population health. "It makes no sense to operate in a vacuum when our education and objectives are so similar."
Kristine Smith, V02, takes a sample from a swan in Mongolia last summer, part of a program monitoring avian influenza outbreaks.
"Instead of triaging an animal, and the problems with it, you're triaging the planet," says Smith, who is the assistant director of the New York-based World Conservation Society's global health program. "We focus on whatever the issues are, no matter how far removed they might be from what veterinarians typically do."
Understanding the mechanism of disease in animals is becoming critical to human health. In the last 50 years, some 70 percent of emerging infectious diseases in humans came from animals, and a large percentage of those came from wildlife, says Saul Tzipori, director of infectious disease research at the Cummings School. "Clearly, most of the diseases that have emerged have come from animals—which highlights the role of veterinary medicine and veterinarians to public health."
Because it often is focused on keeping populations of animals healthy, veterinary medicine is naturally suited to infectious disease work. "We routinely deal with herds and flocks, for instance, and do a lot of preventative medicine and disease investigation with groups," Saperstein says. "At the local level, there is an economic incentive for farmers to work with veterinarians to keep animal herds healthy and respond rapidly to outbreaks."
For instance, if there's a highly contagious infectious disease outbreak in a herd of dairy cows, "our students are well trained to apply tighter biosecurity protocols, do appropriate surveillance in the herds, to root out the cases and resolve the problem in the herd until it is free from that disease," he says.
The scale of responsibility is sometimes much larger. When foot-and-mouth disease broke out in Great Britain in 2001, it wreaked havoc on that country's agricultural backbone as well as other industries, such as tourism. It also brought to the public's attention the importance of good veterinary work, both for security of the food supply and for the economic and cultural value that agriculture brings, Saperstein says.
Under the Microscope
A key component in the one-health effort is research—understanding the roots of disease in order to prevent it from recurring. A number of faculty at the Cummings School maintain vigorous research programs, studying diseases we're all familiar with, such as E. coli, and many others that are below the radar for most Americans, such as shigellosis, an intestinal disease that affects some 165 million people each year and kills upwards of a million children annually in the developing world.
From a small effort that started in the early 1990s, the school's infectious disease research program has grown to become the largest research entity at Tufts University, funded mostly through federal grants. Many of the diseases studied are zoonotic, that is, they are communicated from animals to humans.
Take just one that's being studied on the Grafton campus: cryptosporidium. "It is very common on dairy farms for calves in particular to have a serious bout of diarrhea from cryptosporidium," says Arthur Donohue-Rolfe, interim chair of the department of biomedical sciences. "In fact, it's very difficult if you have this on a farm to get rid of it. And it also affects people."
In 1994 there a major cryptosporidiosis outbreak hit Milwaukee, and some 400,000 people became ill. There's no treatment, and cryptosporidium is resistant to chlorine and to antibiotics. For the vast majority of sufferers, the infection is an unpleasant inconvenience; for people with compromised immune systems, however, it becomes chronic and lowers life expectancy.
People with HIV, for instance, are particularly susceptible. Because of the success of antiretroviral treatment of HIV in countries like the United States, it's now rarely a problem in the developed world, but in some poorer countries in Africa, where HIV/AIDS is still raging, the effects of cryptosporidium are widely felt.
That's where Tzipori, the Agnes Varis University Professor in Science and Society, and his colleagues in the infectious diseases division come in. They are working to develop new therapies for it, and have done studies in Uganda. There are at least two species of cryptosporidium of importance to humans, says Donohue-Rolfe. "One is very prevalent in animals, and also present in humans, and another is more associated with just humans," he says. "Saul Tzipori and his group are trying to study the differences between those two species." (continued)
Story by Taylor McNeil, News Editor, Tufts Office of Publications.
Homepage image by Getty Images/Stockbyte. Tzipori photo by Paul Kapteyn, Worcester Telegram & Gazette. Mongolia photos courtesy of Kristine Smith.
This story originally ran on Sept. 22, 2008.