(a) Define the term "disease." (b) State the difference between resistance and susceptibility to diseases. (c) Enumerate four economic importance of animal disease. (d) List three factors which determine the degree of resistance of an animal to a disease. (e) Outline three conditions that may inactivate a pathogenic organism.
Explanation
(a) A disease can be defined as any abnormality in the functions of the tissues, organs or system of the animal body.
(b) The difference between resistance and susceptibility to diseases is that an animal is said to be resistant to disease when it is not affected by an invading pathogenic disease-causing organism or pathogen while the animal is said to be susceptible to disease when it is not able to ward off the effect of the invading pathogenic organism, in which case it manifests disease symptoms.
(c) The economic importance of animal diseases are: (i) The diseases bring about poor growth of animals (ii) Diseases lead to poor feed utilization by animals due to loss of appetite or anorexia (iii) Diseases bring about low yield of products (iv) Diseases in animals produce low income for farmers due to reduced quantity and quality of products and death of the animals.
(d) The factors which determine the degree of an animal's resistance to a disease are: (i) development of immunity, (ii) specie of animal, (iii) innoculation, (iv) level of feeding, (v) age of animal, (vi) physiological condition of the animal. (e) The conditions that may inactivate a pathogen are: (i) low temperature (ii) high temperature (iii) sunlight and x-rays, (iv) high PH medium (v) low PH medium, (vi) dryness or low relative humidity.
