Biomedical research using animals does not just benefit human medicine: many developments in veterinary medicine could not have been possible without animal research. Animals can suffer from many of the same diseases as humans do, including cancer, heart disease, epilepsy and microbial diseases. The animal research that plays a key role in the search for treatments for these and other shared diseases benefits humans and animals alike.
Many of the same viruses, bacteria and parasites cause disease in humans as well as animals. It is fitting that the first ever vaccine was inspired by dairymaids who were immune to smallpox thanks to being exposed to cowpox. Smallpox was the first disease to be declared eradicated in 1979, thanks to research using horses, mules, goats, rabbits, calves, and mice. The second disease followed in 2011: rinderpest vaccination, developed with research using animals including goats, stopped this infectious disease in cattle in its tracks. Vaccine development has been invaluable to modern human and veterinary medicine, and has helped prevent many diseases including rabies, swine fever, foot and mouth disease, myxomatosis in rabbits, and infectious canine hepatitis (see the RSPCA and this paper for further information).
Pet owners will know that parasites are one of the main reasons to take small animals to a veterinarian. Deworming tablets contain antiparasitic drugs such as milbemycin, which was developed using dogs. Ivermectin is a commondrug used to treat intestinal worms, mites and lice. It belongs to a class of antiparasitics called avermectins, and is also used to treat parasitic diseases in humans including river blindness. William C. Campbell and Satoshi Ōmura were rewarded for their work on avermectins with a Nobel Prize for Physiology and Medicine in 2015, which relied on experiments in sheep, cows, dogs and chickens, and mice.
Aside from infectious diseases, our pets are increasingly affected by many of the same ‘diseases of affluence’ as humans are, including cancer, diabetes, heart disease and obesity. Animal research is contributing to a better understanding of the biological mechanisms of these diseases, with implications for both human and veterinary treatment.
Surgical techniques, radiation therapy and chemotherapy drugs that are used to treat cancer in pets were developed thanks to research using animals. Findings in the veterinary clinic are helping treat human cancer patients, too. In comparative oncology, dogs and cats are studied to help understand how spontaneous cancer formation works. Veterinary clinical trials of cancer drugs in dogs and cats can help develop new treatments for people and their pets. Recent developments in research on the bovine leukaemia virus (BLV, a virus that causes blood cancer in cattle) could also help prevent or even cure the human equivalent, human t-lymphotropic virus.
One in 200 dogs is estimated to get diabetes; the estimate in cats ranges from one in 50 to one in 400. In human as in veterinary medicine, diabetes is managed using insulin injections. The role of the pancreas in diabetes was discovered thanks to experiments on dogs in the late nineteenth and early twentieth centuries. Further dog research on the mysterious ‘pancreatic secretions’ by Frederick Banting and Charles Best resulted in their Nobel Prize-winning discovery of insulin in 1921. While managing human and veterinary diabetes has been possible since the 1920s, much research is still ongoing to find out more about the disease-causing mechanisms in diabetes. The animals used in current diabetes are mainly genetically modified mice and rats. This basic research could contribute to better treatments, and might one day lead to a cure for diabetes that can benefit both humans and animals.
These are just a few examples of veterinary diseases that can be treated thanks to animal research. The fundamental and pre-clinical research that went into developing these treatments relies in a small but important part on studies using animals. Such animal research helps understand biological mechanisms in mammals in health and disease. The genetic, cellular and chemical processes that are the same from mice to dogs to pigs to humans allow findings from animal research to help develop treatments for humans and animals alike.
For more information about animal health, see the website of IFAH-Europe (International Federation of Animal Health Europe), one of EARA’s members.