No, We Don’t Need Another Animal “Model”
When a new rabies strain broke out in Taiwan, local officials decided to inject the rabies virus into beagle puppies to see what would happen.
What would happen is this: As the virus attacked the puppies’ brains, they would exhibit behavioral changes, becoming first hyperactive, then progressively weak. As paralysis spread to their legs, they would become unable to walk. As paralysis spread to their throat muscles, they would lose their ability to swallow. Soon, they would die of respiratory arrest.
PCRM experts called foul. If the idea behind this gruesome proposal was to see whether the virus could infect the dogs and pose a threat to people, we pointed out that it can be safely assumed that the virus would infect dogs. After all, rabies is highly transmissible. Moreover, we showed that the latest scientific methods use test-tube techniques, not animal experiments, and can quickly determine whether existing vaccines can block the virus. As you will read in this issue, the puppies’ fate is still hanging in the balance.
A rush to animal experiments is a frighteningly common response to emerging diseases. Some scientists find ways to cause cancer in animals. Others create genetic changes in animals, feed them fatty diets, and cut out portions of their pancreases to cause diabetes. The idea is to create conditions that resemble—if only vaguely—the human disease.
Why so many animal “models”? One might blame Robert Koch, the 19th-century German physician who, studying cholera and tuberculosis, developed a set of principles to prove that a microbe is the cause of disease. Koch’s postulates, still memorized by medical students today, called for testing suspect organisms in animals.
The idea of using animals as living test tubes has, of course, spread far beyond the world of infectious disease. But cancer, diabetes, heart disease, Alzheimer’s disease, and innumerable other health conditions can now be studied with better methods that zero in on human biology. Starting with population studies, risk factors can be elucidated and can then be tested in clinical trials. Genetic, in-vitro, and pathology studies can help clarify the mechanisms of disease. This does not mean that research is easy, but human-based methods have power and direct applicability that animal research lacks.
Neal D. Barnard, M.D.
President of PCRM