The science of Immunology encompasses the study of the development, anatomy functions and malfunctions of the immune system, all of which are of fundamental importance to the understanding of disease. The immune system protects animals from infection through various lines of defense. If the immune system is not functioning as it should, it can result in disease, such as autoimmunity, allergy and cancer. It is also now becoming clear that immune responses contribute to the development of many common disorders not traditionally viewed as immunologic, including metabolic, cardiovascular, and neurodegenerative conditions such as Alzheimer’s. Veterinary immunology deals the study of all aspects of immune system in animals under biomedical science and related to zoology and veterinary sciences including malfunctions and disorders, but also health, of the immune system in animals. It is interested in how the immune system works, how vaccines prevent disease and why vaccines sometimes do not work and cause adverse reactions. This volume ‘Immunology’ reports basic, comparative and clinical immunology as they pertain to the animal species designated here: livestock, poultry, and fish species that are major food animals and companion animals such as cats, dogs, horses and camels, and wildlife species that act as reservoirs for food, companion or human infectious diseases, or as models for human disease. It brings a clinical framework complete with real-world examples to integrate the theory and practice of veterinary medicine. It also covers fundamental aspects of immunology; methods for the demostration of the immune state, and their application to the diagnosis of disease; vaccines and antisera; physiological and pathological aspects of the specific immune responses. This book provides crucial information not only for poultry health professionals and avian biologists, but also for comparative and veterinary immunologists, graduate students and veterinary students with an interest in veterinary immunology.