Sinopsis
Animals, as well as their humans, live their lives in an unfriendly, hostile environment. They are continually assaulted by hordes of microorganisms such as bacteria, viruses, protozoans, fungi, and parasites. Internally, abnormal cells produced by cellular division must be continually removed from the body. If allowed to survive, they become tumors. Some of these tumors may become malignant and spread throughout the body. Tissues within the body are continually being repaired or replaced as they wear out or become damaged. With all this activity going on in the body, it is a wonder that animals and humans survive in this environment.
The animal body has developed an efficient system of defense against disease-producing agents: the immune system. Components of the immune system patrol the body 24 hours a day looking for foreign and internal enemies. The activities of this system are called immunity; without it, animals could not survive. Immunity can be divided into two large categories: nonspecific and specific immunity.
Nonspecific immunity is composed of several elements: species resistance, mechanical and chemical barriers, the inflammatory response, interferon, and complement. The term nonspecific means that the system responds to all antigenic insults in the same manner, not specifically to any one type of pathogenic organism.
Species resistance refers to the genetic ability of a particular species to provide defense against certain pathogens. For example, canines do not acquire feline leukemia virus, and felines do not contract canine distemper virus. Neither species can contract plant diseases. Knowledge of species resistance can allow a clinician or veterinary technician to focus on the group of diseases seen in that animal species and not spend time ruling out those conditions that do not appear.
The animal’s internal body is protected by a mechanical barrier, the skin and the mucous membranes. If unbroken, this barrier prevents the entry of microorganisms, protecting the underlying tissues from injury. The skin also produces substances such as sebum, mucus, and enzymes that act to inhibit or destroy pathogens. Damage to this barrier allows organisms to reach the internal structures of the body and produce disease. Healthy skin is the animal’s best defense against the world of microorganisms. It is called the “first line of defense.”
Content
- Dogs and Cats
- Ferrets, Rodents, and Rabbits
- Birds
- Snakes, Iguanas, and Turtles
- Horses
- Sheep and Goats
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