Predicting the next outbreak: Disease ecologist wins 2025 Emerging Leader Award

As a child in Virginia, Barbara Han (Ph.D. Zoology, ‘09) stood at the edge of a stream, staring at a frog floating belly up. She couldn’t stop wondering what happened.

Years later, as a graduate student at Oregon State University, she found herself asking the same question, this time armed with microscopes, data and a drive to uncover the invisible forces that shape life and death in the natural world.

That lifelong curiosity has carried Han to the forefront of disease ecology and earned her the College of Science’s 2025 Emerging Leader Award. The recognition feels deeply personal.

“OSU was where my science life accelerated,” she said. “It’s meaningful to get recognized by a place that is such a big part of my journey,” she said.

Now an associate scientist at the Cary Institute of Ecosystem Studies in New York, Han has pioneered the use of machine learning and artificial intelligence to understand when and where new zoonotic diseases are likely to emerge, and why.

A Cascades frog (Rana cascadae), a species found in the Pacific Northwest, mainly in the Cascade Range and Olympic Mountains.

Where ecology meets machine learning

Han’s research sits at the intersection of ecology, computing and global health. She employs complex algorithms to uncover patterns and processes in nature that could lead to the next infectious disease outbreak, such as Ebola, Zika or SARS-CoV-2.

“Those diseases are really driven by animals; they come from nature, but they cause devastating consequences for humanity. That interface is where I feel like I am supposed to be,” Han said.

Her models compare traits of known disease-carrying animals with thousands of other non-disease-carrying species to predict which animals might become carriers in the future.

“Machine learning gives us new ways to see patterns that were once invisible,” she said. “It’s like extending our human senses to understand how pathogens move through nature.”

Her 2015 paper introducing machine learning to disease ecology helped launch a new era for the field. The data and the methods already existed, but she was able to bring them together.

Barbara Han is currently a disease ecologist at the Cary Institute of Ecosystem Studies.

“I think the work that I am the proudest of is not quitting,” she said. “You can’t quit if you really believe the work that you have done needs to be out there. I think perseverance is the most important thing.”

When COVID-19 emerged, her team applied the tools she brought forth to predict which mammals might spread the virus. Many of their predictions were later confirmed in the field.

Her work has extended across disciplines and contents, resulting in collaborations with scientists at IBM, NASA and universities worldwide. Her research has also informed efforts led by the World Health Organization, the Coalition for Epidemic Preparedness Innovations, the Wellcome Trust and multiple U.S. government agencies.

She also serves on the Board on Life Sciences at the National Academies of Sciences, Engineering and Medicine, where she provides guidance on national issues.

A scientist shaped by Oregon State

Oregon State is a cornerstone of Han’s journey from curious child to leader in global disease prediction.

While completing her undergraduate degree in biology at Pepperdine University, Han traveled to Costa Rica as part of an international program studying the biological conditions of the country’s tropical environment. It proved one of the most important experiences in her scientific career because OSU Distinguished Emeritus Professor Andy Blaustein, who would later become her Ph.D. advisor, was part of the program.

His lecture on amphibian behavior and infectious disease sparked a fascination that would define her career.

“We were at the leading edge."

At OSU, Han joined Blaustein’s lab at the forefront of amphibian disease ecology. Her doctoral research focused on a newly emerging pathogen devastating frog populations around the world — a project that echoed her childhood encounter by the stream.

“We were at the leading edge. This was a pathogen that nobody knew much about so every discovery felt new. It taught me how to be used to discomfort,” she said.

The College of Science’s interdisciplinary environment encouraged her to branch out, taking courses in veterinary medicine and collaborating across departments. “OSU let me mix the ingredients in a way that was most true to me and also take that research forward in new directions,” she said.

Her time in Corvallis is filled with fond memories of fieldwork with Blaustein lab members, learning how to catch frogs, collect eggs and wade in ponds with seemingly no bottom. She also learned skills that went beyond the classroom.

“Andy is an exceptional science communicator. He’s naturally gifted at that, and I remember him coaching all of his students. I think that’s part of the reason that I communicate science the way I do. His training was instrumental,” she said.

After earning her Ph.D., Han broadened her expertise beyond fieldwork. She completed a National Science Foundation fellowship at the University of Georgia, learning mathematical modeling, followed by a National Institutes of Health fellowship focused on machine learning for infectious diseases. Each stage of training pushed her beyond her comfort zone and prepared her to connect disciplines that rarely intersect.

Han has been at the Cary Institute of Ecosystem Studies in Millbrook, New York, for 11 years. The institute is one of the world’s leading independent not-for-profit environmental research organizations.

Egg mass of the Cascades Frog (Rana cascadae).

Stay the course

Han’s message to today’s students is simple: stay curious, stay creative and don’t give up. She reminds aspiring researchers that discovery rarely follows a straight path. “Science is supposed to feel hard,” she said. “Every question you’re asking is new — that’s the point.”