Handbook on contagious and infectious diseases in animals / issued by the Quartermaster General's Branch, General Headquarters, India.

Date:
[1944?]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Handbook on contagious and infectious diseases in animals / issued by the Quartermaster General's Branch, General Headquarters, India. Source: Wellcome Collection.

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    When an organism is capable of producing specific disease in an animal, that animal is said to be ‘‘ susceptible ’’ to that disease. Sus- ceptibility varies in degree even in the same kind of animal, the im- portant factors regulating such being— (a) The age of the animal, young animals being often more sus- ceptible than those fully grown. (b) The condition of the animal’s health, robust animals resisting disease which debilitated animals may readily contract. In this con- nection it is important to remember that when contagious or infectious disease prevails, whether amongst human beings or anirnals, causes of exhaustion, debility, or other conditions calculated to lower the resist- ance of the system against attack by the microbial cause of the discase This is specially important in equine Influenza. (c) The manner in which infection is presented, hetkior aerially, by ingestion, or by inoculation, the two latter being most frequent in the lower animals. ‘‘ Acquired ’’ immunity may be ‘‘active’’ or ‘' passive’’. The former is of long duration; the latter is transient (two to three weeks). Active immunity is conferred by— (a) A previous attack of the disease, e.g., Rinderpest, Variola, Strangles. (b) Inoculation of the pure virus, €é. Jos pleuropneumonia Contagiosa and Sheep-pox. (c) Inoculation of attenuated (weakened) virus. The virus may be attenuated by— (1) Heat, e.g., Anthrax, Quarter-ill. (2) Drying, e.g., Rabies. (3) Passing it through other animals, e.g., Swine erysipelas. (Through Rabbits.) | (4) Addition of chemical agents, e.g., Tetanus, a solution of Iodine being used. | (5) Prolonged cultivation on artificial media, e.g., Fowl] cholera. (6) Unknown causes in the bodies of sick or recovered animals, e.g., Rinderpest bile, or the blood of recovered cases of Texas fever. An attenuated virus is termed a ‘' Vaccine’ The use of vaccines for the prevention of disease is year by vear eee more general. The usual procedure is to begin with a very weakened virus and to in- crease the strength at successive inoculations until the pure virus ean be successfully resisted. (d) Sero-virus inoculation, the serum of an immunised animal aha virus of the disease being used either simultaneously (e.g., serum on one side of the body and virus on the other) or serum first followed by. virus. ; ‘** Passive 99 immunity is produced by inoculation of varying quant mentioned methods of conferring active immunity. The immunity con- ferred ‘by the use of a serum 18 very transient, and therefore for
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