For Julia Hyman, a fourth-year student at Harvard Medical School, getting accepted to work with animals at the Franklin Park Zoo near campus this fall was “a childhood dream.”
Yet she immediately found herself helping the zoo’s veterinarians decide the heaviest question a caregiver confronts: Could they save the life of Luther the white tiger? The 14-year-old cat had been stricken with metastatic cancer, and veterinarians spent weeks refining the diagnosis and researching treatments, while balancing likely outcomes against the effect on his quality of life. For example: What would be the full impacts of amputating one of Luther's front legs?
Hyman says the care she witnessed for Luther will influence her care for people: “They took so much time to make sure they made the right decision — what would lead to the least amount of suffering and the greatest amount of benefit.”
Hyman was enrolled in Harvard’s three-year-old One Health Clinical Elective, through which medical students go on four-week rotations shadowing veterinarians at the zoo, with the daily clinical practice providing context for readings and discussions on ecosystems and biodiversity. “The point is for students to understand the role of biodiversity in protecting human health and the interdependence of human, animal, and ecosystem health,” says Eric Baitchman, DVM, vice president of animal health and conservation at Zoo New England, which runs the zoo.
That program illustrates one of several ways that medical students and doctors are striving to improve human health by learning from animals and those who treat them.
In recent years, doctors, veterinarians, and other scientists have come together in conference halls, classrooms, labs, and zoos to share and apply knowledge about the progression of harm and healing across species. Among the more recent projects: to see what the degradation of a salamander species in the waterways of Missouri might foretell about how pollutants harm people exposed to the same water; to explore if a protein that protects an elephant from cancer can be used to develop a treatment for humans; and to discover if treating an antibacterial-resistant infection in the family dog can yield ways to alleviate similar infections in people.
“We’re all the same under the hood,” says University of Pennsylvania School of Veterinary Medicine anatomy professor Peter Dodson, MSc, PhD, who lectures at an educational gathering among medical and veterinarian students there, dubbed the Anatomy Exchange. “An anatomist switching between a human and a dog is like a mechanic switching between a Ford and a Chevy.”
The push for more cross-species research
While doctors and veterinarians have long worked together to heal animals and apply lessons from animal care to people, leaders from both fields have been pushing in recent years to make cross-species observations and research on natural health conditions routine, with the aim of improving health for all.
In an October 2018 article in Nature, 18 authors, most from medical and veterinary schools, advocated for a cross-species approach to disorders affecting the brain and behavior, saying that comparative research on humans and other animals will yield insights and treatments benefiting both. “Many of the same neurological and psychiatric conditions affect humans and animals,” they wrote, “yet clinical and research collaborations between physicians and veterinarians remain infrequent.”
The idea draws lots of nodding heads, though finding the time and money to implement it in medical education and research remains difficult.
“Nobody’s particularly surprised when I talk about this anymore,” says Barbara Natterson-Horowitz, MD, who is asked to talk about it more than anyone.
As a cardiologist at the University of California, Los Angeles (UCLA), Geffen School of Medicine in the early 2000s, Natterson-Horowitz often consulted with the Los Angeles Zoo on monkeys, lions, and other animals with cardiovascular problems. Recognizing that veterinary medicine provides “powerful insights for physicians,” she invited UCLA residents and medical students to join her on rounds at the zoo and veterinary cardiologists to join teaching rounds at UCLA. A comparative process, paired with insights from evolutionary biology, “leads to stronger hypotheses, which accelerate biomedical innovation,” says Natterson-Horowitz, co-director of the Evolutionary Medicine program at UCLA.
Today that approach is sometimes called zoobiquity, after a best-selling book that Natterson-Horowitz and journalist Kathryn Bowers published in 2013. Subtitled The Astonishing Connection Between Human and Animal Health, the book is credited with stirring new conversations and collaborations, including zoobiquity conferences in the United States and several other countries. In addition, physician-veterinarian collaborations today are often constructed under One Health initiatives — a movement that the U.S. Centers for Disease Control and Prevention defines as “a collaborative, multisectoral, and transdisciplinary approach … with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment.”
Such developments “have intensified the collaboration that might have waned somewhat over earlier periods of the 20th century, but has definitely increased over the past couple of decades,” says Jeffrey S. Douglas, communications director at the Association of American Veterinary Medical Colleges.
Bringing medical students and veterinarian students together
Among those collaborations are a few such as the one at Harvard, where medical schools work with veterinary schools and zoos to cross-educate students and practitioners. Students might, for instance, help fix a bat’s broken wing, share knowledge about diabetes treatments in humans to advise on treating a diabetic lemur, and conduct a literature review on possible interventions for cancer in a tiger.
Hyman participated in the One Health elective in September, playing a big part in the literature review for Luther. She was struck by how the veterinarians consulted so many experts and published sources outside the zoo, and weighed how any interventions would affect their patient’s quality of life. Hyman says the staff even envisioned the perspective of his mate.
On Sept. 19, citing a “steep” decline in health and lack of response to medication, the zoo euthanized Luther.
“It made me think quite a bit more deeply about taking a more holistic approach to human health,” says Hyman, who envisions herself as a clinician working in global health. “We [doctors] speak to family members less than we should. We may not be quite as good at thinking through how the patient’s environment at home might be adapted” rather than favoring solely medical treatments.
“We’re all the same under the hood. An anatomist switching between a human and a dog is like a mechanic switching between a Ford and a Chevy.”
-- Peter Dodson, MSc, PhD, University of Pennsylvania School of Veterinary Medicine
The Saint Louis Zoo’s Institute for Conservation Medicine runs a similar initiative with teams of students from two medical schools (Saint Louis University School of Medicine and Washington University School of Medicine in St. Louis), two veterinary schools (University of Illinois College of Veterinary Medicine and University of Missouri College of Veterinary Medicine), and two undergraduate campuses (Fontbonne University and Washington University in St. Louis) in which they explore challenges that threaten wildlife conservation and public health. After working together virtually for weeks, the teams come together for a day to share stories of health ties between humans, animals, and environments at the zoo’s annual One Health Fair.
Among the topics at the fair last April were how palm production threatens orangutan and human survival through habitat destruction; how the decline of vultures in some regions can create human health issues; and how climate change affects the health of Alaska natives and polar bears.
Dean Odegard, MD, was on a team that studied how pollution in Missouri waterways might contribute to endocrine disruption in hellbenders, a type of salamander. Now a pediatrician at St. Louis Children’s Hospital, Odegard says one possible implication is whether hellbenders might serve as a sentinel for the impact of the same pollutants on humans.
Meanwhile, at the University of Pennsylvania’s Anatomy Exchange each fall, where Dodson delivers a talk, 100-plus students from the medical and veterinary schools view cadavers in each other’s labs, with students and residents explaining what’s to be learned from such specimens as a cow’s digestive tract.
First-year medical student Ashley Terry says her biggest takeaway was seeing how the vet school teaches its students to care for multiple types of animals. “As MD trainees, we're only working with humans, so it is sometimes hard to conceptualize how vet students prepare to provide care to many different species,” she says.
While gathering for one evening once a year seems a speck of a step, Dodson says of the students: “We simply want to expand their horizons and get them to understand that humans are part of the natural world. They’re being narrow if they don’t consider the contributions that animal medicine has made to understanding humans.”
Professional collaborations grow
On the research side, medical and veterinary schools have been convening practitioners and researchers from both fields under zoobiquity conferences at, among other places, the University of Pennsylvania, the University of Georgia, Colorado State University, New York University, Tufts University, Washington State University, UCLA, and Stanford University.
At those conferences, physicians and veterinarians have presented talks such as “What the Giraffe Cardiovascular System Can Teach Us About Great Apes and Humans,” “Management of Non-Hodgkin’s Lymphoma in Humans and Dogs,” and “An Equine-to-Human Journey in Musculoskeletal Translational Medicine.”
While researchers have always used animal treatments to develop human applications, One Health and zoobiquity proponents say they see more collaborative research between physicians and veterinarians than before, and that research specifically aims to treat afflictions as they naturally occur in animals, rather than render animals ill in order to help humans.
“We never give dogs cancer,” Joshua D. Schiffman, MD, investigator at the University of Utah’s Huntsman Cancer Institute, says when talking about a project that grew from discoveries about elephants.
"The biggest benefit you can reap from this One Health approach is inspiration. The value is building a cadre of professionals in medicine who understand the interconnections.”
– Dean Odegard, MD, St. Louis Children’s Hospital
In probing why some mammals die from cancer far less often than people do, Huntsman researchers found that a tumor-suppressing protein in elephants, p53, responds more aggressively to cancerous cells than does its human version. The elephant p53 appears less likely to try to repair the damaged DNA and more likely to quickly induce apoptosis — stopping the spread of cancer, Schiffman says, via “massive cell death.”
“The elephant p53 was contributing to the protection from cancer,” says Schiffman, a pediatric oncologist who is working with PEEL Therapeutics and the Huntsman Cancer Institute to develop and test a synthesized version of elephant p53 to spread that protection to other creatures. He says the project involves taking cancer cells from dogs that already have the disease: “We have dog cancer cells that we are growing in mice that we’re treating with an elephant protein to try to make a medicine for human patients. It’s mind-boggling.”
In a neighboring state, Colorado State University and the University of Colorado have partnered to explore if activated mesenchymal stem cells in dogs can be used to overcome antibacterial resistance to chronic implant and wound infections, which is driven in part by the increasing prevalence of drug-resistant bacteria.
Other comparative research projects explore ways to address sleep apnea, stem cell replacement, regeneration, cardiovascular disease, epilepsy, pain, cognitive decline, anxiety, infectious diseases, and more.
While those projects have far-reaching, tangible implications (stopping cancer), some of the other cross-species initiatives seek more subtle impacts, adding layers to the educational foundation of medical students.
“The biggest benefit you can reap from this One Health approach is inspiration,” says Odegard, who participated in the One Health project at the Saint Louis Zoo. “The value is building a cadre of professionals in medicine who understand the interconnections.”
Sharon Deem, DVM, PhD, director of the Institute for Conservation Medicine at the zoo, says all of these endeavors will pay off in various ways for humans, animals, and the environment. Says Deem: “We can learn from each other.”