Human medical knowledge is rooted in the torture of animals. While most of us think of rats or chimps, dogs have made some of the greatest contributions to science. The good news: The new research is just as much about saving their lives as ours.
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Canine testing: A history
Like it or not, all of human medical knowledge is rooted in the torture of animals—dating back to the 2nd century. Starting in the 2nd century with Galen of Pergamum through Ibn Zuhr (or Avenzoar) in the 12th century—early scientists/physicians performed experiments on living animals to better understand anatomy. Dogs—plentiful in number and easy to access—were an obvious choice. In 16th century Italy, Andreas Vesalius performed public vivisections—cutting open a dog—while his students speculated about each organ’s function. Note: Anesthetics had not been invented at the time.
Modern testing: dates back to 1937—when hundreds of patients died from a strep treatment drug that contained a poisonous solvent. It sparked a new law requiring mandatory animal testing for all human medicines—which remains a standard phase of clinical trials to this day: “[T]he first step of this process has been to test the candidate molecule in at least two animal species: a rodent (mouse or rat) and a non-rodent, such as canines and primates.”
Beagle, the pet subject: In the early 20th century, scientists used dogs grabbed off the streets—or from pounds. But they “rarely knew exactly what they were getting.” Hence, the growing preference for a purebred—which represented a “standard” or “normal” dog. Beagles became the #1 choice simply because scientists chose breeds they knew.
In 1950, Americans fell in love with Snoopy, a new beagle character in the Peanuts comic. Four years later, the American Kennel Club listed it as the most popular breed in the country. Such popularity extended into science as well. In 1950, the Atomic Energy Commission launched the most expansive beagle study ever conducted in a multi-sited investigation into radiation and longevity, occasioned by the U.S. detonation of atomic bombs in Hiroshima and Nagasaki.
Scientists spent the next couple of decades inducing tumours in beagles—to study the long term effects of radiation. Since they worked out so well, the dogs also became test subjects for drug testing. The revised FDA laws in 1962 specifically recommended the use of dogs (in effect, beagles) for toxicity tests. They remain lab subjects to this day around the world—from the US to China. But many countries—including India—have officially pledged to minimise animal testing. It just hasn’t happened as yet.
Our debt to dogs: A number of Nobelists used dogs to make remarkable breakthroughs—including developing insulin to save diabetic patients; and connecting vitamin deficiency to deadly cases of rickets. A number of key medical advances wouldn’t be possible without dogs:
- Intravenous injection
- The first electrical defibrillator
- The electrocardiogram (ECG)
- Design of the pacemaker
- Hormonal therapies for cancer
- Stem cell therapy to treat muscular dystrophy.
The big Q: Why dogs?
Chimps and other apes are used as test subjects because they share 98% of their DNA with us. Mice are small, cheap and plentiful. So why use dogs?
Shared diseases: Dogs and humans suffer from a number of similar diseases. Example: Granulomatous meningoencephalomyelitis, or GME, in dogs comes with seizures, vision problems, sluggishness and a strange head tilt—a lot like multiple sclerosis (MS).
Shared physiology: One reason why scientists looked at dogs to understand cancer: we both get tumours when we get sick—unlike mice:
[M]ouse models of cancer have limitations in mimicking human cancers because tumours arise spontaneously in humans, whereas tumour formation must be induced in mouse models… Canines are excellent models for comparative oncology since they spontaneously develop the same types of cancers as humans.
Very often, it is the same mutation in the same gene that drives the emergence of tumours. For example, cats get a type of breast cancer that is associated with the same protein—HER2—as one of the most aggressive breast cancers in women. Another example: “bone cancer osteosarcoma is nearly identical—both clinically and genetically—in dogs and people.” It is why both humans and dogs respond to the same drugs: “most common therapies for human non-Hodgkin lymphoma work in dogs, and those that don't work in dogs don't work in people.”
Ironic point to note: Breeds like golden retrievers experience high rates of cancer precisely because of our obsession with purebred dogs. In other words, we made them more prone to cancer—which makes them handy test subjects.
An inbred ideal: The exact same factor that makes dogs more susceptible to genetic disease—in-breeding—also makes them perfect test subjects:
Dogs have been an especially appealing target. Intense human selection, especially over the last few centuries, has created a staggeringly diverse collection of canines, from Chihuahuas to Great Danes, and hundreds of reproductively isolated breeds, which often suffer from high rates of disease.
It is much easier to connect genetic factors to disease when the patient’s genome is a result of human tinkering.
A shared environment: As pets, dogs share the exact same living spaces as us—unlike mice or chimps:
Dogs make for better clinical trial subjects because they are exposed to much of our environment — the same air, microbes and water — and a number of environmental factors have been linked to cancer in humans and in dogs. Compare that with “a mouse in a cage down in a basement somewhere,” [professor of medicine and pathobiology Nicola] Mason said.
For example, one set of researchers is looking at the link between pollutants and lymphoma among golden retrievers.
Above all this: There are no confidentiality rules. Or rules banning testing highly experimental drugs on dogs—unlike humans:
To be eligible for a clinical trial of a new drug, a person with cancer typically needs to fail the standard of care — often chemotherapy — or to combine the standard of care with the trial drug, “because it’s considered unethical to give a person something experimental without having provided them the best treatment that we know works,” said [professor of medicine] Alexander Bick…
Dog owners can send their pets “right into a clinical trial without having their immune system already worn down by earlier treatments”—which helps give “clearer data” on the efficacy of a drug.
A big shift: From test subjects to beloved pets
All of this sounds dire but dogs have benefited from being domesticated pets—unlike hapless rodents. Scientists learned a lot about canine health—even as those beagles were being tortured in labs:
We also know more about dogs and how to care for them. Many vaccines, including for rabies, parvo and canine hepatitis, relied on beagle research. So too did modern canine nutritional guidelines and medications such as Anipryl, which treats Alzheimer’s-like conditions in dogs.
Today, canine health has become a legitimate focus of research—not just as a byproduct of testing of human meds.
Where we are now: Today, dogs are brought in willingly by doting pet owners—looking to improve their lives—not just to save humans. This also means the pooches are better protected:
[S]o there is a limit to the type of experiments that can be done on them. No veterinarian is going to euthanize someone's dog at the end of a trial to get a better sense of how a drug worked, for example, even though that could be incredibly informative. "You can try just about anything in the rodent world," says [veterinarian expert] Dottie Brown… "But these are people's pets."
In 2004, Tasha the boxer became the first dog to have her genome sequenced. Today, genetic research into dogs has become routine—with dog owners eager to participate in the testing—not to save humans but their pets.
The bottomline: The biggest upside of drugs trials on pets is that it is mostly a win-win proposition:
Of course, there's always the possibility that pet clinical trials will never translate to people, and that they'll just help veterinarians develop better drugs for dogs and cats.. "If we save these dogs, it has an impact on every single family that owns a dog," says [geneticist] Matthew Breen… "When I get involved in these trials, it's about helping the family. If we're helping the human or the dog, is there really any difference?"
Reading list
Animal Research is best on the history of dogs as test subjects. The Washington Post pays tribute to the contribution of beagles—and looks at why dogs are suited to cancer research. New York Times looks at the shift toward using pets for medical research. Science.org offers a more detailed and balanced view. Vice has more on cats—while Smithsonian magazine looks at rats. This research paper by Aysha Akhtar makes a strong case against animal testing.
