It's not a matter of if a worldwide pandemic will strike but when, say experts like veterinarian and epidemiologist Jonna Mazet, a professor in the Department of Medicine and Epidemiology in the University of California, Davis, School of Veterinary Medicine. That's why Mazet, who leads an early warning pandemic system called PREDICT, monitors the world's hot spots, or "hot interfaces" for signs of emerging diseases. Her goal is to prevent or contain the next outbreak of human immunodeficiency virus (HIV) or other emerging diseases. Pandemics besides HIV that have emerged in the past include influenza, severe acute respiratory syndrome (SARS), and Ebola, but the exact nature of future threats is unpredictable and that's part of what makes the task so daunting.
Worldwide travel, land use changes, and "our demand for goods from all over the world is really creating the perfect storm for pandemics," warns Mazet, who brings a unique veterinary perspective to the field of epidemiology. That perspective is important, she says, because, "Sixty percent of all emerging diseases of people come from animals and most have wildlife origins."
Mazet describes "hot interfaces" as places and circumstances where humans and animals come together, in particular, "where we have high biodiversity, high human population density, and the environmental conditions that are ripe for this kind of transfer of disease." Centers of focus include Southeast Asia, South Asia, the Amazon basin, and Africa's Congo basin, where "you have the environmental conditions and drastic changes in land use that put the ecological system out of balance."
Examples of drastic changes that open the door to disease include those occurring in places in Africa where rivers are drying up because of a combination of climate change and purposeful agricultural diversion. As a result, "animals and people come together and share small watering holes for drinking, bathing, and washing," creating a prime breeding ground for disease and transmission.
PREDICT partners are experts in wildlife surveillance, risk modeling, and sophisticated molecular diagnostic techniques and work to identify both known and new suspected pathogens, the earlier the better. Methods include geospatial modeling, genomics, molecular virology, and targeted field studies. The investigators look for mysterious patterns that might include dead animals or sick people, and even test apparently healthy animals that can transmit disease without exhibiting symptoms at these hot interfaces.
Internationally, PREDICT is funded by a $75 million federal grant from the US Agency for International Development's (USAID) Emerging Pandemic Threats Program, but the investigators also communicate with agencies that conduct national surveillance, such as the U.S. Department of Agriculture and the Centers for Disease Control.
"We don't really have a good handle on the diversity of pathogens that are out there, so we have to try to find and characterize the unknown before it spills over and causes an epidemic that could quickly become a pandemic," she says. "If we can detect and minimize the impacts of epidemics, we'll be ahead of the game and can reduce the risk of pandemics. We've got the technology to accomplish that, but we need to commit to it."
The Association of American Veterinary Medical Colleges (AAVMC) encourages students who are interested in veterinary medicine to consider public health careers. In Mazet's case, she earned her doctor of veterinary medicine, master of preventive veterinary medicine, and her PhD in epidemiology from UC Davis. She recommends her line of work for students with an interest in veterinary medicine who want to solve global health problems for vulnerable populations. She uses a One Health approach that recognizes that sustainable solutions will only be found by considering the connected and interactive influences on animals, people, and the environment. Mazet recommends that students get critical experience in One Health by working in public health, animal agriculture, environmental management, conservation, and natural resource agencies and nongovernmental organizations, as well as by working with professors and scientists on their research projects.
"Dr. Mazet and her colleagues are out to stop the next HIV-like pandemic before it starts," says Bennie Osburn, interim executive director of the AAVMC. "It's a perfect example of the "One Health' approach that veterinarians take to solving problems at the nexus of animal, human, and eco-system health."