Efforts to understand susceptibilities to specific cancers among dog breeds,8 as well as possible lower rates of cancer relative to body mass in large animals such as elephants,9 may also provide insight into genetic factors mediating protection from and susceptibility to cancer.
Such a comparative medicine approach, in fact, has a long history. Rudolf Virchow, the father of pathology, was a proponent, famously stating in the 19th century, “Between animal and human medicine, there is no dividing line — nor should there be. The object is different but the experience obtained constitutes the basis of all medicine.” Yet physicians today rarely think in these terms. Recently, Natterson-Horowitz’s book Zoobiquity and ensuing conferences on the topic have helped generate renewed interest. More broadly, an approach called One Health is also growing in prominence, which considers not just human and veterinary medicine, but also the environmental factors (biodiversity, ecology, socioeconomics) affecting and affected by both.
At the zoo, the boundary between human and animal medicine seemed an artificial construct. Nature does not hold human disease on a pedestal, nor does it preferentially target diseases to humans. Yet talking to many physicians, veterinarians, and students reveals an asymmetry — the veterinary world routinely looks to human medicine for insight, while the opposite is not true. Human doctors are often surprised to hear that diseases affecting humans are also found in other animals. The oft-heard response of “Animals get that too?” when speaking to my colleagues belies the prevalent human-centric view of medicine. As a result, insights from veterinary medicine that may have major impact in understanding human disease are missed.
However, there are few concerted efforts in the biomedical research community to systematically explore the vast opportunities for comparative medicine research. Grants for physicians, veterinarians, and researchers working together in collaborative projects may help. Notably, the revolution in genomics technologies now provides a key to unlock many previously inaccessible comparative medicine questions. Now would be a uniquely productive time to invest in this approach. Both human and animal medicine stand to benefit immensely.
Education can also play an important role. Medical education may be reinforcing the boundaries between human and animal medicine by not instilling in medical students an appreciation that nearly every disease manifests in other species in both interestingly similar and different ways. Veterinary medicine is not similar to pediatrics, as some physicians may quip, and its potential to inform human medicine is not limited to just zoonoses. Veterinary medicine is also geriatrics, oncology, cardiology, dermatology, rheumatology, behavior — all the disciplines seen in human medicine. Incorporating even modest comparative medicine and evolutionary medicine teaching in medical school curricula would help ensure that the countless variations in natural disease that may inform human medicine are not overlooked. Certainly, the goal would not be to teach veterinary medicine to medical students, but rather to raise awareness among students that they are seeing only a small slice of physiology and disease and that the many idiopathic unknowns of human disease often have illuminating counterparts in other animals. Human medicine is the tip of the iceberg, and briefly introducing comparative medicine would at least teach students that there is an iceberg. Medical students would be enriched by this broad way of thinking, stimulating research ideas early in their careers, especially among aspiring physician-scientists, and facilitating closer ties between human and animal doctors over the long term.
Nearly every day at the zoo, the veterinarians and I would make fascinating, unexpected connections between human and veterinary medicine. One memorable experience occurred while I helped treat a bird with a dilated esophagus. One of the veterinarians mentioned as a matter of course that pathologic dilation of the foregut in some birds (parrots), called proventricular dilatation disease (PDD), is caused by a neurotropic virus. My thoughts immediately raced to achalasia, a similar disease in humans whose cause has long eluded research. Searching the literature, I learned that a viral etiology for achalasia had indeed been proposed for decades and that the laboratories of Ganem and DeRisi who discovered the viral cause of PDD had been investigating achalasia tissues for a similar virus. Though this search has not yet borne fruit, these frequent interspecies disease connections were exhilarating.
Helping with the routine animal care at the zoo was also humbling. My first morning was spent trying to coax a 150-pound African desert tortoise to stay still just long enough to slide an x-ray film under him while also balancing a portable x-ray machine on a tripod above. He would not stay still, but we gently persisted to confirm he did not have bladder stones, a dangerous condition to which the species is prone. Checking the glucose levels of a ferret with an insulinoma (pancreatic tumors prevalent in the species), vaccinating a headstrong reindeer for West Nile virus, and helping resuscitate a premature newborn goat were just some of the many meaningful moments I shared.
Sadly, Jeffrey our meerkat died one week after being admitted to the hospital. As we cared for him during his stay, we watched fondly as he stretched, despite his weakness, to the tall lookout posture for which meerkats are famous. We learned that another group of veterinarians (A.M. and M.G., personal communication) had recently reviewed a large number of cases and found that nearly a quarter of meerkats die of cardiomyopathy, most often of the dilated type we had seen — a possible new species-specific disease withpotentialfor research. I thought of Asclepius who learned secrets of healing from the animal kingdom, the snake of his serpent-entwined rod that is the symbol of medicine. As Oscar Wilde and George Bernard Shaw said of Americans and British, human and veterinary doctors sometimes seem like colleagues divided by a common language. But together, we can cure our patients’ shared ills.
Pages: 1 · 2
More Articles
- Elaine Soloway's Rookie Transplant Series: Packing; Balconies, Stairs, Stoops, and Folding Chairs; Imposter
- Treating Blood Pressure to a Lower Goal Particularly For Those Over the Age of 50
- Safari To the Serengeti For A Birthday Trip, Both Hair-Raising and Life Transforming
- Between Dusk and Bedtime: Suppressing a Sleep Hormone