Part 9

Dry, warm beds with plenty of air and light are essential to vigorous health and the usual damp, filthy, dark pens are depressors of the vital forces and virtually invitations to hog cholera as to other diseases. The close packing of swine under manure or under rotten piles of straw where they often suffocate each other is to be carefully guarded against. It is a sufficient commentary on this to say that for every kilogramme of its body weight, the horse consumes daily 13,272 grammes oxygen, the cow, 11,040 grammes, and the pig, 29,698 grammes. This is in perfect keeping with the high normal temperature maintained by the latter animal. In the interest of health the pig requires twice the breathing space for every 100 lbs. of his weight that is demanded by either ox or horse. What violence is done to this demand of nature in the daily treatment of the hog!

Fresh, sound, wholesome food is no less a desideratum. Yet the omnivorous pig is condemned to become the scavenger for the kitchen, the stable, the feeding pen, the slaughter house, the creamery, the sugar works, the brewery and even the rendering works. Whatever is considered unfit for human use is thrown into a swill barrel, and as this is never emptied it becomes the field of endless decompositions with the production of the most varied toxins, ptomaines and enzymes. Many of these chemical toxic products cause gastro-intestinal inflammation with vomiting, bloody diarrhœa and tenesmus, and derangement of the nervous and other functions as manifested in weakness, staggering, dulness, stupor, etc. Death may follow in a few hours and the cases are set down as acute forms of hog cholera, rather than the simple poisoning that they are. All the same they pave the way for the attack of hog cholera if its germ is present even in a form of little potency. All such foods should, on the contrary, be fed fresh and after boiling.

Salt in excess, the brine of salt meats or fish (containing toxins), the powdered soaps used in kitchens and added to swill, mouldy bread, cotton seed meal fed in any considerable proportion in the food, and even an exclusive diet of corn (maize), must be guarded against.

The crowding of many pigs in a small yard where they root continually in each others’ droppings and their own, should be avoided. Individual pens, or pens holding two or three only and kept clean are to be preferred, and still more a wide grassy range where they may escape from their own filth. The long feeding trough should be discarded in favor of one into which the pig can introduce his nose only. The nose itself will introduce filth ferments, but, where there are not specific-plague-germs, it is the quantity that tells and the exclusion of the foul feet is an important consideration. To these various poisonous products of saprophytic ferments it often happens that the older swine have by continuous exposure, acquired a comparative immunity, while the young growing pigs perish in large numbers.

Feeding pigs in confinement, without green or animal food is very liable to induce costiveness and indigestion which pave the way for the inroad of the hog-cholera germ. A certain allowance of green food, slops, and, above all, a variety of food constituting a well-balanced ration are always desirable.

Again, the constitution of the pig is often material. On the continent of Europe it is the high bred English pigs that suffer most, and in all cases a lack of the rugged vigor attained through an active, open air life lays the system more open to a violent attack. Too close breeding must be similarly avoided, together with breeding from the immature, the weak and the debilitated. In this connection it is important to rid the herd of parasitisms which not only weaken the system and lessen the power of resistance, but by the bites or the inflammation induced, open channels for the introduction of the hog-cholera bacillus.

Prevent the Introduction of the Bacillus. The above precautions are important in obviating infection and favoring a milder type of the disease when the germ has been introduced, but they are but palliatives at best, and will not hinder the development of a plague in the presence of an active and potent virus. Adopted alone they are worse than useless as a means of extinction of the germ: they tend to preserve it. The exclusion of the hog-cholera germ is the one essential thing in prevention and whatever comes short of this must have at best but a partial effect.

Avoid pens, pastures or streams that drain swine enclosures higher up. Discard all provender or litter that has come in contact with other pigs or their products. Allow no visitors to the herd such as butchers, dealers, drovers, that have habitually come in contact with other herds. Exclude as far as possible domestic animals (dogs, sheep, cattle, fowls, pigeons), and even vehicles coming from places where hogs are kept. Wild animals such as buzzards, and other carrion feeders, must be especially guarded against. Wild rabbits and hares (jack rabbits), skunks, wood chucks, minks, rats and mice should be exterminated. Small birds and flies are difficult to deal with but the latter may be destroyed by acids, copperas, or sulphites on the manure and the former may even be exterminated when hog-cholera exists in the vicinity.

Sows should not be sent from herd to herd for service or otherwise, and any swine that have been hired out, or sent to an exhibition, and all that are acquired in any manner, should, on arrival, be excluded from the herd and held in quarantine, well apart for three or four weeks, and finally washed with carbolic acid soap before they are admitted.

The pestilential prevalence of hog cholera and other swine plagues to-day is largely the result of the great industrial and commercial activity of modern times. In America the disease was comparatively unknown until after 1830, and in Europe even later. But with the advent of steamboat and railroad, the few pigs raised in separate pens, or secluded localities, and killed and cured near by, gave place to the large herds, sent when fattened to great markets where pigs were collected from distances of many hundreds of miles, the stock animals and the fat occupied in succession the same boats, cars and yards, and, as a matter of course, the virulent germs were concentrated and diffused through the infected places and things. We cannot go back to the antiquated safer methods, but it would be possible to so regulate our commerce, that the evil could be reduced to a minimum. Separate cars, loading banks, chutes, alleyways, and yards can be reserved for fat swine going to immediate slaughter and no animal having passed through any of these should be allowed to be taken out for stock purposes, unless it has been passed through a rigid quarantine. The places and things used for such fat swine should be disinfected at intervals, and the manure and offal should be disinfected, or exposed to a boiling temperature for a sufficient length of time before removal from the premises. Stock swine on their part should be shipped only on a certificate of the complete immunity of the herd and locality from which they come from swine epizoötics, and of the roads or vehicles by which they reached the shipping point. They should be debarred from all yards, loading banks and cars or boats used for fat hogs, and admitted only to such as have just passed through a thorough disinfection. They should be sent directly to their destination, or if to a market, for purposes of sale, it should be well apart from that used for fat swine, and the loading banks, chutes and yards should be entirely distinct and should be thoroughly disinfected on every occasion after use. The millions now lost yearly from swine epizoötics might well warrant the inconvenience and expense entailed by such precautions. Heavy penalties should be imposed on those shipping pigs from infected localities, on those making false certificate, and on all who in any way violate the law.

Independently of State or local authorities the stock owner can do much to protect himself. He can make a number of pens large enough to hold 2 or 3 pigs each, safely fenced off from one another and so constructed that no drainage can take place from pen to pen. Then in winter in the absence of flies, and with rats, mice, and birds excluded the opportunity for the extension of infection from pen to pen can be kept at its minimum. All pigs must be kept apart from the manure heap, and in summer the manure must be so treated as to destroy the larvæ of flies. All food and water that might convey infection must be guarded against. Then if one pig is attacked it will only be necessary to destroy it and its two fellows in the same pen, and even if those in adjacent pens are killed or quarantined the loss will be a trifle as compared to the ruin of the whole herd, as usually happens. Prompt disinfection of the pens and manure is imperative, and the same would apply to the person and clothes of the attendant, and to all stable utensils.

Immunization by injection of sterilized products of the bacillus, has not proved satisfactory. In 1880 I applied this to two pigs, causing a transient fever, after recovery from which, the subjects resisted exposure to infected pens and pigs, and even virulent inoculations. But they failed to thrive well. Later experiments by Drs. Salmon and DeSchweinitz respectively, also proved unsatisfactory. The latter separated and injected the enzymes, but lost 50 per cent of his cases, the survivors proving immune, with the drawback of troublesome local lesions. The enzymes obtained from cultures in milk could be used safely on guinea pigs in the dose of 0.01 grams and in some cases even up to 0.04 securing immunity. But the great risk of an overdose, the frequent local lesions, and the subsequent unthrift, have prevented the adoption of the method.

Disinfection. The experiments of the Bureau of Animal Industry show that, apart from freezing, four months in the soil, serves to render the bacillus harmless.

From .75 to 1 per cent of quick lime added to soil in the form of lime water, destroyed the virulence in 11 days.

Lime can be employed as a thick whitewash on pens, fences, yards, etc., the precaution being taken to see that it is newly burned, caustic and applied in sufficient amount. Lime that has been kept absorbs carbon dioxide and loses its disinfectant property. If ¼lb freshly made chloride of lime is added to each gallon of the caustic lime white wash the certainty of success is insured. Lime water has the advantage of being applicable to grassy surfaces, without proving hurtful to the vegetation. For buildings and yards it furnishes a ready means of estimating the thoroughness of the application.

Sulphuric acid (1:100 or 1¼ oz. to 1 gallon) makes a good disinfectant for buildings and yards. Like lime this can be used freely without fear of poisoning the animals.

Carbolic Acid, 5 per cent, can be used with great safety. The Bureau of Animal Industry advises the combination of this with sulphuric acid, which adds greatly to its solubility.

Formalin may be employed, diluted one to forty of the solution (1 per cent of the gas) in buildings and on woodwork generally. It may also be applied in the form of gas by heating the solution in closed rooms. Like carbolic acid it is especially applicable to cars, boats, and other vehicles.

Corrosive Sublimate (1:500) makes a convenient and cheap disinfectant, with the drawback that it is poisonous, and destructive to metals. Mercuric Iodide though more potent is also more expensive. Blue stone (2:100) and zinc chloride (10:100) are also effective but poisonous.

The failure to stamp out hog cholera in England and America has been largely chargeable on the appointment of laymen to do the work of the expert, and no less so on the attempt to deal with the disease in hogs in transit or in the market rather than in the farm where they have been raised or kept. Let the fat and stock markets be kept rigidly apart, together with the means of conveyance to and from these, and let no stock swine start for a market or destination without a certificate of the soundness of the locality from which they came, and the purity of the means of transit, and we shall have taken a long step toward the final extinction of the pest.

State limits and rights stand in the way of successful work, but this can be partly met by a frontier supervision by national officials, and should be further, by a prompt and hearty coöperation of the sanitary officers of the two states involved. When it becomes possible to trace infecting hogs, back to the infected place in another commonwealth, and punish the offender who shipped them, we shall be within sight of a satisfactory control or extinction of hog cholera.

Extinction of Hog Cholera in Herds and Districts. As in all deadly plagues this should be a recognized governmental function to be carried out at public expense. It is a question of political economy and its neglect is subversive of prosperity not in Agriculture alone but in all public industries whose workers must subsist on the fruits of the soil. The $10,000,000 lost yearly by the farming community, is a dead loss, not to agriculture alone, but to the prosperity of the nation, the markets of which would be revived and improved by such a yearly sum expended.

The existence of the disease at any point should be reported by the stockowner or guardian, under penalty in case of failure. When the nature of the outbreak has been certified by the expert, the district should be scheduled, and the herd appraised, slaughtered and all products disposed of in such a way as to prevent any escape of infection. The carcasses may be burned, buried deeply, or boiled and rendered. The buildings, yards, utensils, fences, manure, cesspools, and infected fields should be thoroughly disinfected, or secluded from all animals for a year. The owners of the herd should be indemnified according to appraisment, and not to exceed ¾ths of the actual market value, provision being made that no award shall be made if the herd sickened within a fortnight after their arrival from another State, or in case the owner, has concealed the existence of the illness, or has otherwise deliberately or carelessly contributed to its spread.

Many minor rules and restrictions will be required to fit the general measures to individual cases and local conditions, and these require the direct supervision of an expert, and not of a mere business manager or layman.

Therapeutic Treatment. With state, county or municipal measures for the extinction of hog cholera, treatment is to be condemned, as calculated to encrease and spread the infection. But until the states can be educated out of the past wasteful system, into economical measures of extinction, the swine breeders are entitled to whatever salvage they can secure through therapeutics. For acute cases there is no hope. For the chronic a clean, dry, comfortable pen, well disinfected, and a moderate diet of varied and laxative food are essential. Wheat, bran or middlings, with corn, oat, barley or linseed meal may be allowed in form of a mash. A little green vegetable food may be added. Medicinal agents may be used to meet special indications, but when a whole herd must be treated at once, antiseptics and febrifuges have apparently proved the most generally helpful. The Bureau of Animal Industry especially recommends the following: Wood charcoal, sulphur, sodium sulphate and antimony sulphide, of each 1 lb.; sodium chloride, bicarbonate and hyposulphite, of each 2 lbs.; mix thoroughly and add to each feed in ratio with the size of the patient. In suitable cases, this is said to improve the appetite and contribute much to convalescence. Modifications will readily suggest themselves to meet individual conditions and different stages of the disease—antithermics, eliminants, calmatives. stimulants, tonics, etc.

Serum Therapy. This has been especially exploited and advocated in America by De Schweinitz of the Bureau of Animal Industry, and Dr. Peters of Lincoln, Neb. In Europe, Perroncito has prepared an antitoxin. The serum is produced in the body of the cow or other animal which is inoculated repeatedly with gradually encreasing doses of living hog cholera cultures and with solutions of the bacilli and their products, for a period of eight months, or until no reaction takes place from large doses, and the blood serum added to cultures of hog cholera bacilli causes agglutination of the latter. The serum is further tested as to its power of preserving Guinea pigs inoculated with a lethal dose of live hog cholera cultures. After separation from the blood the serum is concentrated until it reaches a standard at which 10cc. proves curative to a pig of 40 to 60 lbs. weight.

It proves most successful in animals in which the subacute or chronic form of the disease has just begun. One injection only was given to each animal. Of 1923 cases treated (1897–8) 30 per cent. died, and 70 per cent. recovered. Of 3197 in abandoned herds (checks), 81.24 per cent. were lost. (De Schweinitz.)

One drawback was found in the short period of immunity secured, the susceptibility reappearing as soon as the antitoxin had been eliminated from the body. This was met in part by using sterilized cultures (toxins) along with the serum.