[All Rights Reserved.] VETERINARY PAPERS FOR FARMERS.

Otago Witness, Issue 2455, 3 April 1901, Page 6

[All Rights Reserved.] VETERINARY PAPERS FOR FARMERS.

VII.— ANTHRAX. (Bt Pkofessok Wobttey Axe.) Part II — Susceptibilitt. All our farm animals, we ha\e remarked, are capa"ble of contracting anthrax, but there exists among them a considerable difference in regard to susceptibility, and, therefore, greater risk of infection in respect of some animals than of other?. This difference is indicated, though imperfectly, by statistics furnished by the Board of Agriculture, in which wo find that in the five years from 1888 to 1892 there were attacked 1514- cattle, 147 sheep, 701 swine, and 50 horses. Susceptibility in the ox is far above that of any other of our farm animals, while dogs are least receptive of all. Sheep, swine, and horses occupy an intermediate position between these two extremes. We are familiar with many instances of sheep and horses grazing with impunity on pastures which imariably impart the disease to oxen. It has been generally observed that cattle when thriving are more readily infected than others in a less forward state. This may, perhaps, &ei^e to explain why animals so frequently occupy infected pastuies for se\ eial weeks in the early ?pnng without harm, and fall Mctims to the disease when a better or moie robust condition X established. Or it may be but a coincidence, since the lov er temperatures of spring would be le^s favourable to the re pioduction and spread of the urns than the warmer day-, of tunimcr. ACCESS OF THE POISOX. Expeiiment and ob' citation ha\e shown that anthrat infection may enter the body by one of chauneis.

1. Through a wound or abraded sui face. 2. By the mouth with food or water. 3. By the lungi ■nnh the respired air. Of these tho two former aie by far the moic common modes of access, in the lower animals; indeed. I am not aw aio that infection has been shown to take effect in them through the bicathing organs In man the disease is frequently transmitted by inhalation of anthrax spores. This is n common form of infection in wool-soi ters, ing sorters, and hair-cloth workerp. Altfiough the channels of infection are spoken of as three, it i». I think, highly probable that a wound or abrasion of bkin is an essential condition of acce=s of the vim". As wr> have previously pointed out, anthrax prevalence ii greater in young than in old animals, and this special liability of the former would seem to result in a large measure from the frequent occuirence of wounds in the mouth, arising out of displacement of teeth during the second dentition, and no doubt all animals contract the disease through wounds otherwise inflicted, as by thornp, coarse food, and a urious foreign substances taken up with it On two or three occasions we have known anthrax to arise shortly after the upo of furze, and to discontinue on its being withdrawn from the food supply. Inoculation of the wius by the sting of wasps and other insects must be recognised as a probable mode of transmission, and may account for many of those sporadic outbreaks which aie such a notable feature in the records of tho disease. SOUHCES OF THE \ IRTJP. With regard to tho souiccs from which the \ irus 1? demed it is impossible to overlook the fact that with anthrax, as with some other diseased of which we ha\e a long and painful expciience, we owe much of it to our foreign relations. Anthrax poison is being imported into England from many pa-ts of the world, and soy, n broadcast o\or our pasture and arable land. Foreign hides, wool, and bones aie constantly affording examples of this traffic in infection, and as to foreign hoirs and hoofs there is no doubt that they, too, ai-v3 bearets of the contagion. The danger and deadliness of some sample^ of what are termed "dead" and ' wasted" liklcs, that* is to say hides from animals which have d i-ecl , or have been destroyed on account of sickness are well known m the tanning trade, and the mortality among stock arising out of the pollution of streams by tannery refuse and the infection of land by the overflowing of such streams is far more considerable than is generally believed. Refuse from the sorting of wool, comprisingpieces of skin, dried blood, animal excrement, earth and other extraneous matters, besides fragments of the wool itself, has proved a fiuitful soutce of anthrax, when used for manurial purposes. In addition to that which is> imported trom abroad our nr\ti\e stock cf virus is constantly being multiplied in the bodies of farm animals which suffer and die from the disease. MEASUKES OF SUrrKESSIOK. An outbreak of anthrax o.i a farm is one of the most serious events which can befall the stock owner. If it occurs for the first time it generally leaves behind the seeds of future havoc, and if it is one of f-e\eral outbreaks it adds to iho already existing stock of contagion and amplifies existing danger, until, by repeated occurrence of the disease, grazing becomes impossible. This is the unfortunate condition of many of our best pastures to day While these lines arc being written we are called for the third time during tlvj past eight months to advise as fro the re- : currence of anthrax on a particular farm. Here the disease has existed for f3veral years. It followed upon the repeated diessing of certain pastures with animal refuse from neighbouring kennels. The infected pastures had in accordance with our advico ceased to he ftocked, but by some means or other the ■* irus has now reached the farmstead, and for the first time the disease appears in the sheds. How far it may proceed to spread from this new centre it is difficult to say, but in view of thp traffic of animals and men from the sick box and the unguarded disposal of manure there are many possibilities of dangerous scattering of the poison, as from shed to shed, or through the manure 011 to the cultncted land. To suppress and prevent the disease is a. matter of the first importance, but before «uccesi can be hoped for in tins connection, farmers must be brought to leah-e its trua nature, and to appreciate the laws which govern its spread. The viru", as we ha\e seen, is contained in the blood, and with it niar esoape during life thiough any of the natural outlet? of the body, or, after death, in the 1 act of dissection. Wherever, therefore, the blood is spilt, theie the germs of the disease may be foam. To intercept and destroy thcfo is tho object of all measures of suppression and pre\ention. Karly lecogmtion of the disease in a heid 1 or flock is, thercfoie, of the first importance. : Anthrax has no symptoms peculiar to itself, j and considering (hem alone, it is impossible to say with ceita'nty whether we are dealingwith it or some other fever of an acute and virulent character. If, however, sj mptoms d) not satisfy ovr diagnostic requiiements. tho side lights obtained by consideration of the hietory and circumstances of the outbreak, together with post mortem signs, usually afford reliable indications of the disease. Failing in this, microscopic inspection of the blood and experimental "test cf its virulence afford absolute pi oof. Wheic doubt exi-ts. it need hardly be said that one or both of these methods of inquiry should plways bo resorted to. The difficulties which boset an inquiry of this nature place it altogether beyond tho power of the stock-owner, and call imperatively for the services of the veterinary surgeon. It is, neveithele=9, desirable that tho farmer should be made familiar with tho warning notes of the disease that he may appreciate and guard asrainst tho danger which confronts him. I have el=ev here observed that the sudden death of an animal without obvious reason is usually the first noticeable event in an outbreak, and for sanitary purposes this should at all times be regarded with suspicion, especially on farms where the mala'ly has previously been known to exist. On the first aupearance of the disease, prompt removal of tho healthy from th» F ick is urgently called for. In carrying out this it is common practice to lemove the founer at once to a fresh pasture without t'lo adoption of any measure of precaution against tho transference of infection by them. As a consequence, it often occurs that no sooner' has tho change been made than the disease reappears in the herd. These recond outbreaks) have given usen to strange ideas as to the origin of the affection, but it is only necessary to say that they usually result either fiom tho removal of animals already infected, but which had not then giv en evidence of the ditcate, or fiom infection of the second pastmo by the virus-laden feet of the animals lemovod from tho first. To guard against

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such untoward results the feet of animals removed from an infected place should be first thoroughly cleansed and soaked with some disinfecting solution, or dusted over with chloride of lime, or both. When this has been done the herd or flock should be placed in a yard or shed thinly littered with straw and well sprinkled with a suitable disinfectant. They should be daily visited and examined by a veterinary eurgeon. and any and every sign of ill-health at this time ehould be regarded with suspicion of anthrax. If a temperature of 105deg be found in any of the herd this should be deemed conclusive evidence of the existence of the disease. By prompt removal and destruction of cases of this kind the malady is brought under control, but where these measures of prevention r'-^ npn-Votprl im 1 nnimpls which now fall are eHowed to remain in the herd and die, they egain becomo new centres of infection from \...^n I-.. ui»edie spie&ds to others. A period cf six days should be allowed to lapse before iho cnimals leave the ehed or yard, ar.d the same course of disinfection of the feet already prescribed should be repeated before they enter a fresh pasture. Men attending Ihe quarantined animals should freely disinfect their boots each time on leaving the yard or shed. Dogs and poultry should, for the time, be kept in confinement, and strangers forbidden to enter the premises. When the cattle are removed the litter and manure should be burnt, and the ground surface again sprinkled with antiseptic solution. Mangers, troughs, fittings, and utensils should be subjected to thorough cleansing and disinfection. The practice of bleeding animals ■when stricken with sudden and acute sickness, so often reported to by herdsmen and shepherds, is one fraught with the greatest danger, and has, on many occasions, been the means of transmitting anthrax infection directly from the sick to the healthy, through ihe instrument employed in the operation. Blood drawn from infected animals invariably finds its way to the manuro heaps, and thtnee to pasture or plough land, to infect the soil and perpetuate the disease. In this way, fodder and 'green crops of every description may become contaminated with the virus, and form starting points for fresh outbreaks. Moreover, this practice of bleeding anthrax animals often leads to extension of the disease to pigs and dogs, who may consume the specifically infected blood, and to the contamination of ponds and drains in the vicinity of the homestead. The perennial question — can anything be done to rid our pastures of infection? — naturally arises in considering the prevention of anthrax, but in the present state of our knowledge it only admits of a negative answer. Dressings of lime and salt, breaking up the land, and a course of tillage have frequently been resorted to separately and together, but without diminishing the virulence of the so. If. however, we are unable to suggest a remedy for this growing evil, we are far from admitting that the subject ha 3 received all the attention it deserves, or that means may not yet be discovered of destroying the virus. We have already pointed out the danger attaching to the use of foreign animal products for mammal purposes, but it is much to be feared that tinder our present system of agriculture these materials have become indispensable, and must, therefore, be continued; if this be so, then the farmer must endeavour to protect himself from their hurtful influence by insisting on their being treated by some such agent as sulphuric acid or other potent germicide, before being applied to th& Jand. It is almost invariably the case that the virus of anthrax enters the body either as specifically infected food or ■water, and where, as usually occurs with animals in confinement, the former is made up of several ingredients, such as roots, cake, meal,, hay, etc.,. it is always difficult, and frequently impossible, to fix upon the offending article. A close and searching inquiry, however, should be made into the history and use of each and all of them by a competent person, and pending his decision both food and water should undergo a complete change. SLAUGHTER OF THE STOCK. One of the most important steps in the suppression and prevention of anthrax is the prompt slaughter of animals affected with or nispected of the disease. Twenty years ago 1 pointed out the fact that until one or two ] ours before death, the anthrax parasite is i. resent in. the blood in such small numbers i"<3 to be with difficulty discovered, while im- -. lediately after death immense numbers are i )und in every drop. It may, therefore, be ( ;neluded that the great bulk of the contat ion is produced during the last hour or two < f the animal's life. To allow this stage to ] 9 reached is to encourage the propagation < i the organism and the multiplication of infection. As to what animals should be icgarded with suspicion, as distinguished from others actually affected, I should cay that when the existence of anthrax has been established in a herd, all having a temperature of 105deg should be dealt with as infected animals and destroyed. In destroying anthrax-stricken animals, the spilling of blood should be strictly guarded against, for reasons already explained. The poll-axe and the knife must give place to prussic acid, a poisonous dose of which may be injected into \hz lungs, through the walls of the chest or directly into one of the large veins. This operation requires for its performance both technical knowledge and skill, and can only bo legitimately and safely performed by a qualified veterinary surgeon. DISPOSAL OF THE DEAD. Earth burial is, at present, the only practical means we possess of disposing of the victims of contagious disorders. Destruction by heat and by the employment of chemical agents, co much to be desired in respect of th'S and some other virulent ailments, presents too many difficulties to hope for its adoption. In disposing of anthrax carcases, selection of a suitable site for the grave is of the first importance. Here some place to •which animals have no means. of access should, if possible, be fixed upon— such as a wood, a copse, or piece of waste land. Fading these, a field under plough must be selected. Wherever the choice may fall, the site should L- well away from all sources of drinking •water, whether river, drain, pond, or weli. Six feet is the prescribed depth of the grave, of which the bottom as well as the carcase ehould be covered with 6in of lime As i frequently occurs that virus-laden blood will escape from the various-inlets and outlets of the body, these should be freely dusted with disinfecting powder both inside and out, and afterwards plugged with wisps of hay, pre- \ iously soaked in some strong antiseptic solution; the month, eyes, anus, and genital passage should all be vo treated. The feet, too which almost invariably carry the contagion, should be thoroughly disinfected, la removing the carcase to the grave, it must either be conveyed on a board, or, what is better, in a cart. In no case should it be drawn over the ground, as is frequently done, without protection against soil contamination Post mortem examination, when necessary, should be made by the grave side. in carrying this out, a good deal of earth

under and around the body will be saturated with blood. Every particle of this must be. thrown into the pit after the carcase, and, lastly, the grave and parts around, as at ell as> the boots of those engaged in ihe work, should be soaked with disinfecting solution.