Text book of veterinary medicine, Volume 4 (of 5)

by James Law

Another line of treatment which deserves to be further exploited is the use of antitoxins on infected animals. An immunized animal may be again and again inoculated at intervals of a week or two until it has been stimulated to produce antitoxin in large amount. Then after three weeks interval its blood serum or blood, may be sterilized by heat, the resulting coagulum washed in distilled or boiled water, and filtered, and the filtrate injected subcutem on the infected animal.

Prevention. This is most effectively secured by sanitation of the soil and buildings. Thorough drainage to secure perfect and constant æration leads to destruction of the anærobic germ, or the suspension of its pathogenic quality. Thorough culture contributes largely to this sanitary æration, while baking of the surface counteracts it. When thorough drainage is impossible it may be desirable to subject the land to gardening or to the production of crops that are to be used for human consumption and not for domestic animals. Kitt’s suggestion, to soil cattle on hay, produced on such lands, and to exclude from the infected lands all animals that by wounds or sores near the feet, or by raw gums from shedding of teeth, furnish infection atria for the poison, is insufficient, as stalled cattle occasionally suffer.

When an open porous soil maintains the infection by reason of the presence of an excess of decomposing organic matter, that may be largely remedied by a free application of quick lime. This hastens the decomposition of the organic matter and after a year or two, when that has been largely disposed of, the good effects may be expected.

An important measure is to exclude from fairs, markets, and above all from clay or other dense wet soils into which they might convey the germs, all animals brought from infected soils.

Disinfection of the buildings where diseased and infected animals have been is an essential measure. Wells and streams receiving the drainage of infected lands must be carefully avoided.

Diseased animals must be carefully isolated, and all their droppings, and products of every kind disinfected.

The carcasses are best cremated or rendered under superheated steam under pressure. Solution in sulphuric acid may be employed. If none of these are available they may be deeply buried in dry porous soil well apart from any risk of drainage into wells or water supplies. The area occupied by the graves should be fenced in so that no cattle nor sheep can gain access to it, and any vegetation grown on the graves should be burned. The danger of the germs being raised to the surface by soil water or earth worms must be recognized and any consequent evil guarded against. The carcass should not be cut open but buried in the hide, or if the latter is preserved it should be treated with a chloride of lime solution. If a carcass is opened for scientific purposes, great care must be taken to avoid the distribution of the bacillus in soil appropriate to its preservation. The meat should not be preserved for human consumption unless it has been cooked under pressure at a temperature of 240° F. The object is not to destroy any poison which would be fatal to man, but rather to prevent the spread of the spores on new soil and the extension of the area of infection.

The reduction or prevention of sudden plethora was formerly availed of to lessen the number of victims and it is well to still bear in mind that this has an appreciable though limited effect. As a means of reducing plethora a free bleeding was resorted to when the period of yearly prevalence approached, and no less when the disease had already appeared in a herd. I can mention an instance in which infection was carried on the fleam from the first animal bled (the sick one) and caused the fatal infected swelling around the phlebotomy wound in the next seven animals operated on. Another objection to phlebotomy is the tendency to a rapid reproduction of blood, which the depletion brings about, and the supervention of a greater danger than before, in the course of a month or more. Purgatives and diuretics are somewhat less objectionable in this sense. Careful feeding to keep the animal constantly in good condition does something to obviate sudden plethora and its attendant dangers, and thus an allowance of grain or linseed cake through winter and early spring, or when the pastures are bare, will bring the animals through in fine condition, and ward off the danger that comes from a sudden access of rich aliment.

Another measure was the insertion of a seton in the dewlap. The theory was to counteract plethora but the benefit probably came rather from the formation of an actively granulating wound, which came in contact with the ground and received the bacillus, but in which the abundance of air, and of active leucocytes checked the propagation of the germ and the occurrence of a fatal infection. A certain grade of immunity was the natural result in many cases.

Immunization. As the first attack of emphysematous anthrax secures for the subject of it immunity against a second, we are furnished with a reasonable basis for the practice of artificial immunization. This has been attained by a variety of methods, the essential feature of each being the subjecting of the system of the animal to be treated, to the action of the toxins of the specific bacillus.