ABSTRACT
One of the things that distinguishes veterinary from human medicine is that veterinarians are frequently called upon to diagnose and treat disease in populations as well as individuals. Practitioners are frequently called upon to participate in local, state, and federal disease control programs. To perform in this capacity, veterinarians must understand and be able to communicate the scientific basis of these disease control programs to their clients. Causes, or determinants, of disease include the etiologic agents directly responsible for disease and other factors that facilitate exposure, multiplication, and spread in the population. In food-producing and other animals raised and managed for profit, the impact of disease is frequently described in terms of performance or economics, rather than morbidity and mortality. Likewise, decisions as to whether to treat or cull the animal may be determined in large part by economics.
