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The Animals Inside Us

The Animals Inside Us

By Melissa Pandika


Looking to animals for clues about our own health is good for all patients — with or without fur. 

By Melissa Pandika

Barbara Natterson-Horowitz’s life was changed in a huge way by one of her tiniest patients: a kitten-sized emperor tamarin monkey named Spitzbuben. Although the UCLA cardiologist spent most of her time seeing patients and teaching medical students and early-career doctors, she was also on the medical advisory board for the Los Angeles Zoo, where she occasionally consulted for zoo veterinarians. One spring day in 2005, the chief zoo veterinarian called Natterson-Horowitz to examine Spitzbuben, who was suffering from heart failure.

When Natterson-Horowitz arrived, she did what she normally does to soothe her human patients. She knelt in front of the monkey and gazed deep into her round, glassy eyes. She immediately felt the veterinarian grip her shoulder.  

“Please stop making eye contact,” the vet said. “You’ll give her capture myopathy.” 

Natterson-Horowitz stepped aside, puzzled. What was capture myopathy? When she later researched the condition, she learned that it’s a form of heart damage animals can experience due to the stress of being captured by a predator. What’s more, locked eyes can trigger capture myopathy. To Spitzbuben, Natterson-Horowitz’s warm gaze was saying, “I’m going to eat you.” Then something clicked in the doctor’s mind. She had seen a similar condition in humans, called Takotsubo cardiomyopathy — heart failure caused by intense emotional stress. Physicians discovered the condition a few years ago — but vets had known about the animal equivalent for decades.

The goal is treatments that heal all species. 

The experience opened Natterson-Horowitz’s eyes to how much doctors and vets could learn from each other. In recent years, she and other health specialists have encouraged greater collaboration between veterinary and human medicine in an effort to better understand diseases and develop treatments that heal all species. Researchers from both fields are increasingly working together to cure cancer, obesity, infertility and other ailments. 

Natterson-Horowitz coined the term “zoobiquity” to describe this interdisciplinary approach. In 2011, she launched the annual Zoobiquity Conference, where vets and doctors jointly present case studies and go on “Walk Rounds” through the local zoo to discuss its patients. Institute of Medicine president Harvey Fineberg will speak at this year’s conference in New York City on November 2. Fineberg’s participation holds symbolic importance, Natterson-Horowitz said. The Institute of Medicine is a highly influential organization that advises Congress, federal agencies and others on health issues. 

Vets and doctors jointly present case studies and go on “Walk Rounds” through the local zoo to discuss its patients.

“The case is pretty overwhelming that you can’t really comprehensively and knowledgeably deal with human diseases without being connected to animal disease,” Fineberg said. 

Zoobiquity is also the title of Natterson-Horowitz’s book, which she co-wrote with science writer Kathryn Bowers. The book, published in 2012, explores the many health conditions we share with animals. For example, jaguars can suffer from breast cancer, and koalas can catch chlamydia. Gorillas in the wild experience clinical depression, and canaries faint when they’re stressed. 

Natterson-Horowitz’s meeting with Spitzbuben was serendipitous, but not unexpected. Her love for nature and wildlife dates back to her childhood trips to national parks. Today, she lives in the Santa Monica Mountains in a house surrounded by huge sycamore trees with her husband, two teenagers and two dogs. She starts each day with an early morning hike, spotting coyotes, deer and the occasional rattlesnake along the way. 

Dr   Barbara Natterson-Horowitz treating a gorilla placing a tube in its mouth. Other attendees are in the bacgroumd

Dr. Natterson-Horowitz checking a gorilla for signs of heart failure, the leading cause of death for gorillas in zoos — and a leading cause for human admissions to hospitals.

Vets and doctors jointly present case studies and go on “Walk Rounds” through the local zoo to discuss its patients.

Natterson-Horowitz isn’t alone in her quest to bridge the human-veterinary medicine divide. In 2006, the American Veterinary Medical Association established the One Health Initiative to build partnerships among doctors, vets and other health professionals. The nonprofit focuses mainly on diseases that spread from animals to humans, or “zoonoses,” like West Nile virus and avian flu. 

Jaguars can suffer from breast cancer, and koalas can catch chlamydia. Gorillas in the wild experience clinical depression. 

Zoobiquity extends to other diseases, too, including cancer. Scientists typically study the disease by inducing it artificially in mice. Although they’ve cured cancer in mice, they’ve failed to translate the results to humans. So the National Cancer Institute (NCI) decided to take a zoobiquitous approach, launching the Comparative Oncology Program to support research into naturally occurring cancers in dogs in 2003. The major advantage of this approach is that the tumors emerge spontaneously, just like they do in humans, so they better reflect the natural complexities of cancer. Canine and human cancers also share many genetic and other features. And since dogs and humans live together, they’re exposed to the same environmental factors. 

Studying naturally occurring cancers may not speed up drug development, but it might make the process more efficient by giving scientists “additional, complex information” that improves the chances that a trial will be successful, said NCI veterinarian and Comparative Oncology Program director Chand Khanna. 

The strategy has shown promise so far. If all goes well, researchers at the University of Illinois at Urbana-Champaign will take a drug they showed in an NIH-funded study to be safe and effective in dogs with osteosarcoma and lymphoma to human clinical trials in mid-2014. Since the compound enters the brain, unlike most cancer drugs, the clinical trial will target brain-cancer patients, who have few therapeutic options.

Dogs and humans share another chronic disease: obesity. In fact, research has shown that obese dogs tend to have obese owners, and with this in mind, a number of dog/owner fitness programs have sprung up. Thank Dog! Bootcamp, for example, offers hour-long classes in the U.S. and Canada consisting of cardiovascular, strength and obedience training. 

And since the exchange goes both ways, veterinary science is learning and benefitting from human medicine. Researchers at the Smithsonian Conservation Biology Institute in Virginia are applying assisted reproductive techniques being used with women to preserve fertility in endangered species, including cheetahs, coral reefs and wild horses. 

A drug shown to be safe and effective in dogs with osteosarcoma and lymphoma will go to human clinical trials in mid-2014.

It wasn’t so long ago that health professionals for people and animals were one and the same. In the 1800s, town doctors commonly treated humans and their farm animals, but increasing urbanization at the turn of the 20th century made veterinary medicine less lucrative. Around the same time, federal legislation pushed veterinary schools to rural areas, while academic medical centers rose to prominence in wealthier cities.

The gap widened further as physicians became  “fixated on a hierarchy that put MDs on top of the pyramid, and anyone who’s not an MD below,” Natterson-Horowitz said. Doctors are often unaware of the rigor of veterinary education, she added. (In fact, admission to vet school is more competitive than med school admission; there are 141 med schools in the U.S. but only 28 vet schools.) 

In addition to research partnerships, another solution is to create opportunities for veterinarians and physicians to collaborate on joint cases. Besides the Zoobiquity Conference, doctors and vets could one day include each other in the referral process, suggests Peter Rabinowitz, associate professor in environmental and occupational health sciences at the University of Washington and founder of the UW Human Animal Medicine Project. A vet who notices that a dog and its owner are overweight might refer the owner to a physician. The clinicians might then discuss both patients and recommend they enroll in a joint exercise program.

But zoobiquity goes beyond bringing physicians and vets together. Evolutionary biologists, ecologists and public health officials should also have “a place at the table,” Natterson-Horowitz said. “I’m convinced that bringing the fields together will generate important scientific advancements that can benefit not just humans, but all patients on the planet.”


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