As people have become more health-conscious, and bonds between humans and their animals have deepened, the demand for veterinary specialties such as dermatology, behavior, pathology, and surgery has risen. The following is part of a series exploring these specialties and the University of Illinois veterinarians who practice and teach them.

When your pet gets sick, you want your veterinarian to diagnose the problem and find a treatment that works. When your veterinarian tries to diagnose a disease, he or she must ask: “What tests can help me accurately identify the problem?” Once a diagnosis is made, you will ask “How serious is this problem? What is likely to happen to my pet? How well do certain drugs and treatments work? How long is my pet likely to live a comfortable, happy life?”

According to Dr. Ronald Smith, veterinary epidemiologist at the University of Illinois College of Veterinary Medicine in Urbana, these questions are best answered through epidemiology, the study of health and disease in populations of animals.

For example, how well a diagnostic test works is ultimately determined through clinical research with real patients. Veterinarians who work directly with patients keep records of the test results and subsequent progress of the patients. Clinical epidemiologists collect this information and analyze it to determine the accuracy of the test