See the new face of veterinary medicine

OVC shows the media how animals can make us sick and help us get well

By Barry Gunn – Illustration by Keyser

Hear the word “veterinarian” and the first image that probably springs to mind is someone in a lab coat vaccinating your dog or cat.

But wait. If you think the impact of veterinary medicine on your life is limited to the impact of pet care on your wallet, you’re wrong.

In a world where newspaper headlines shout that society is on the brink of a new pandemic, where SARS and West Nile virus have been pushed aside by fears of avian influenza, veterinarians are increasingly on the front lines of issues that have global social, economic and public health implications.

With that in mind, the Ontario Veterinary College, in conjunction with the Council for Advancement and Support of Education (CASE), brought some of Canada’s leading health and science journalists to Guelph in March for a three-day crash course in how veterinary medicine affects human health.

The 2005 CASE Media Fellowship program offered reporters a rare opportunity to meet with leading researchers at OVC to explore the roles that animals play in making us sick and helping us get well.

The program also provided OVC researchers with insights into how the news media work and the reporters’ perspectives on current issues in public health and scientific research.

“One of the things we need to do is showcase the new face of veterinary medicine,” says Prof. Carlton Gyles, OVC’s interim dean. “Most people see the traditional face of veterinary medicine when they take their pet to their practitioner. That’s important. But public health in general is an area of expansion for veterinary medicine worldwide. We need to get that message out.”

From a media perspective, there have certainly been enough wake-up calls in recent years with outbreaks of illnesses such as SARS and West Nile virus, but it still doesn’t occur to most reporters to make that link between veterinary science and issues affecting people.

“I have to confess that I thought veterinarians and people in veterinary science studied animals, and I didn’t see where the intersect was,” says Helen Branswell, a longtime reporter with Canadian Press who has covered the health beat for five years.

“I was surprised at how much relevance there was to the work that I do. Some of the issues covered in these sessions were like the interviews I do on a weekly basis.”

The veterinary profession has undergone profound changes since Andrew Smith founded the Ontario Veterinary College in Toronto in 1862. In those days, the school was primarily focused on the horse. By the time OVC moved to Guelph in 1922, the focus was shifting toward servicing the livestock industry. Small-animal medicine — looking after people’s pets — was not a priority.

That’s certainly not the case today. There are some eight million dogs and cats in Canada, and owners value their pets’ health. The evolution of veterinary medicine has mirrored the shift in demographics and social values, with companion-animal practice becoming increasingly sophisticated and specialized in areas traditionally associated with human medicine, such as oncology, cardiology and neurology.

At the same time, farm-animal practice has long since moved on from providing mainly emergency medicine — the call in the wee hours during foaling season — to overall health management, helping farmers maximize production while protecting the well-being of their animals and the health of consumers.

Meanwhile, over the last 20 years, new threats to human health have arisen that have animal links and shine the spotlight on veterinary medicine, including:

• the emergence of diseases such as SARS and mad cow disease;
• the resurgence of diseases like tuberculosis in wildlife populations;
• the emergence of antimicrobial-resistant pathogens;
• water quality issues;
• climate change and its potential for allowing the spread of illnesses like West Nile virus;
• the potential menace of bioterrorism; and
• growing urbanization and globalization, which make it possible for new diseases that do emerge to spread like never before.

Some 80 per cent of the new infectious diseases to emerge in the past couple of decades are considered zoonotic (they can be transmitted from animals to humans). The experts say we can expect to see a new disease on the horizon every 12 to 14 months. By this time next year, avian influenza could be old news. Or it could be the pandemic the experts have been predicting.

This intermingling of human and animal biological systems has no precedent. While summarizing the convergence of these trends recently, Brian Evans, a 1978 DVM graduate and the federal government’s chief veterinary officer, told a group of first-year students that no matter which career path they choose in veterinary medicine, “you will be in public health.”

It’s clear the public will continue to look for answers to the health questions that crop up in the media every day.

“As a society, we’re far more attuned to global warming, to what’s in our food,” says Tanya Talaga, a Toronto Star health policy reporter who covered the Walkerton disaster and the SARS outbreak. “We want to know why one in three of us are touched by cancer; we want to know all these things. And it has to do with the food we eat and the air we breathe and the environment we live in.”

OVC clinical studies professor Scott Weese says the belief used to be that things like rabies were the only zoonotic diseases worth worrying about.

“Beyond that, the thinking was, there are horse bugs and dog bugs and cat bugs and human bugs, and there’s not much interaction. But now we know there are more bugs that are going between different species.”

In recent years, Weese and OVC researchers have collaborated with Mount Sinai Hospital and microbiologists in Quebec on studies that have focused on a pair of bacteria that are potentially deadly to both humans and animals: methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile.

Both are traditionally associated with infections originating in human hospitals. Both can be connected with the unanticipated increase in antimicrobial-resistant pathogens due to the use of antibiotics to treat other illnesses. And both can jump from humans to animals and back again.

“Whether animals are getting sick or they’re creating a reservoir for human infection, either situation is a concern,” says Weese.

Veterinarians aren’t just on the front line when the worlds of science and politics collide; sometimes they also get caught in the crossfire. Take, for example, the debate over the effects on human health of antimicrobial drug use in food animals.

Antibiotics give producers valuable tools for preventing and treating disease in farm animals, as well as promoting growth, but there are costs along with the benefits. As in human medicine, there are concerns that antimicrobials are being used too liberally.

The problem is that the pathogens targeted by the drugs are highly adaptable. Resistant strains of Campylobacter, Salmonella, E. coli and Enterococci not only pose problems for farmers, but they can also spread to humans, with serious health consequences. Exactly how it happens — how Salmonella, for instance, strings together the complex array of genes that code for resistance — is not fully understood.

“It’s not as simple as Farmer Joe treats sick cow with tetracycline and you end up with this complex Salmonella strain,” says Prof. Scott McEwen of OVC’s Department of Population Medicine. “As far as we can tell, it’s a lot more complicated and takes place over a long period of time. The bottom line is that drug use anywhere can affect resistance anywhere, and it’s impossible to predict what’s going to happen. We should try to reduce the use of drugs as much as possible in all the realms, whether it’s in animals or people. Because these genes do find their way around.”

It’s that level of uncertainty — or rather, the difficulty of distinguishing between the real and theoretical risks to human health — that intrigues the Globe and Mail’s André Picard.

“People want a no-nonsense direction,” says Picard, author of two best-selling books on Canada’s health system and one of the country’s leading public policy writers.

He says a good example of real versus theoretical risks emerged last fall when studies revealed higher-than-expected levels of flame-retardant chemicals in supermarket fish, meat and dairy products.

“You’re telling me there are flame retardants in food, but what I want to know is: ‘So what? Is this going to kill me? Or can I still enjoy my steak and get a little fire retardant and so be it?’ That’s what people are looking for: ‘Tell me the bottom line.’ We don’t do a very good job of that.”

OVC clinical studies professor Mark Hurtig says that, in the past, when people would ask him what he did for a living, he’d say he was a veterinarian.

“Now I don’t know what to say. I usually say I’m an arthritis researcher. Yes, I study animals, but I also work on large collaborative projects that are mostly focused on people, using the natural history of arthritis in animals as a model.”

As director of the Comparative Orthopaedic Research Laboratory — the name given three labs making up a pre-clinical core facility for the Canadian Arthritis Network — Hurtig leads an interdisciplinary group focused on osteoarthritis and cartilage repair techniques.

Rather than treating the disease once it gets established, he is particularly interested in early interventions — treating or repairing injuries before they develop into arthritis.

“That early intervention step is going to be huge in the next 10 years,” he says. “Our lab is a proving ground for those new concepts.”

Veterinary medicine is also a proving ground for new cancer treatments, allowing researchers to study naturally occurring cancer in dogs and cats, for example, and to conduct clinical trials that parallel human research.

In one project, OVC scientists are working with researchers at McMaster University on gene therapy that targets dendritic cells to trigger the dog’s own immune system to attack cancer cells. In another project, clinical studies professor Paul Woods is working with Toronto’s Sunnybrook Health Sciences Centre to investigate the effectiveness of metronomic chemotherapy — low continuous doses of chemotherapy drugs aimed at cutting off the blood supply to tumours.

Many OVC research projects have potential spinoff benefits for people. Dogs, for example, share our environment and develop many of the same types of cancers. And because of their shorter lifespan, it’s possible to learn a great deal about how the disease progresses in a short period.

It’s their ability to look at issues from a slightly different perspective that would make veterinarians a valuable resource during a health crisis, says Hannah Hoag, a Montreal-based science journalist who writes for the McGill University Health Centre and publications such as Nature and Canadian Geographic.

With an M.Sc. in genetics and molecular biology, Hoag felt right at home talking shop with OVC researchers but was still surprised at the level of research taking place here.

“I realized the link between animal health and human health was there, but admittedly, I hadn’t realized the extent of research that a vet college was involved in — research at a more basic level rather than just at a clinical level,” she says. “That’s what interested me the most and definitely put the vet college on my radar.”

Just as a deadly outbreak of hamburger disease in the western United States drove food safety to the top of the health agenda during the Clinton administration, the Walkerton tragedy in May 2000 made E. coli a household name in Canada.

A year later, an outbreak of waterborne illness in North Battleford, Sask., made the public aware of Cryptosporidium, a parasite that commonly causes diarrhea in cattle. It has also emerged as one of the most common causes of waterborne disease in North America.

At the same time, well-recognized food-borne bacteria such as Salmonella have continued to be a concern.

“There’s been a substantial increase in public concern about food and water safety over the last 10 to 15 years,” says Prof. Jeff Wilson, an epidemiologist in OVC’s Department of Population Medicine. “Interestingly, though, the reported rates of those infections have for the most part tended to go down.”

Working in collaboration with the Public Health Agency of Canada, Wilson is focused on co-ordinating outbreak response, surveillance and research into major zoonotic, enteric, food-borne and water-borne disease outbreaks.

They can expect to be busy in the coming years.

“We can anticipate there will be additional new emerging infections,” says Wilson, just as Weese expects new zoonotic diseases and Woods hopes for breakthroughs in cancer research that will benefit both animals and humans.

What Canada’s chief veterinarian told veterinary students about their role in public health parallels what their professors were telling Canada’s major media about the link between veterinary science and medical research: “Expect the unexpected.”
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