LIVE STOCK DISEASES. ANTHRAX.

Otago Witness, Issue 2527, 20 August 1902, Page 6

LIVE STOCK DISEASES. ANTHRAX.

The rerpht pronouncement of Mr Gi'ruth, head of the Government Veterinary Depaillncnt, thai anthrax has again and again been introduced into various pait3 of the Noith Island must ha\e attracted a good deal of attontio'i, and arouae-d a deuire on tli*-' part of owners of farm animals for information in regard to the precis© nature of tin* fata] malady and the causes for its outbreaks I'nhke brsxy disease among Mioep flocks, the infested areas of which are but partial and well defined in countries whoie it has been prevalent for generations, the geographical distribution of anthrax is limited only by that of tlio ammals on which it prey 5. and the=o rango from man down to the smallest rodent. In almost every country m the world it lias established a permanent exi.-tence in the soil in oiio part or another, and many of the animal plagues, murrain-, and distempers of anoient writers were no doubt due to its virulence. "It appears." says I'rofnssor Robertson, "as an epizooty among ihe herd-> of the Laplanders; as such t'le Ra->ian, too, well knows the deadly "laswa." and as an epidemic a-nd epizooty among men and animals over the \a-t plains of Siberia, wheie it is fcpoken of a* ' Siberian plague ' Neither do the gieat upland df^wrta of Contra! Ahia, escape its visits, and it ih well known amoiig horses over Central Hindost.ui. Tbo great Australian stockowner dvcad> the hnvoc of the scourging 'Cumbei'and disease,' while it is not unknown on i}»<- wild pampas of tlie South America* lopulilic, cr on the rolling prairies of the (. rt.it Wf-t«n State of the northern con-t"it-i/t : while from ihe dc-tnption of the a'lmpiit* to which animals are subject, it M-rrn- to bo as well known, if not so frocjucntly rcccgtiisod, in. the fertile rallojv and ])'ateaus of southern ond central Africa, whric our acquaintance v/ich it as 'Cape hoi=e sickness' is intimate a<» it is over the central plains and ri\ er basins of middle and western EuiQjjfi* I

Professor Wortley Axe, one of the foremost and most frequently-quoted authorities on the subject, describes anthrax "as essentially a parasitic affection, communicable from animal to animal, not only between individuals of the same species, but from members of one species to those of another ; thus it may pas 3 from the ox to the horse, from the horse to the dog, and so on. Here the offending parasite is not, as in so many other instances, derived from the animal kingdom, but consists of a minute plant or fungus known as the 'bacillus anthracis.' On gaining access to the blood of a susceptible animal, th.s organism undergoes rapid multiplication and development, and in doing so not only tends by its vast numbers to block up tho \esscls and impede the circulation, but it also forms and excretes a poison, the effect of which is to excite an acute and fatal fever." This, the professor says, is one of the most fatal and widespread of the specific contagious fevers. Of its history in. tho United Kingdom but little is known, but there is now reason to believe that many of tl>o«e outbreaks which in the past were spoken of as ''blood disease," '"splenic apoplexy," etc , were of this nature. Until comparatively recent times nothing was known of its precise origin Its frequent occuncnce in animals in a thriving condition led to its being referred to a to rich and generous diet, but its rt-peated extend-on to poor, ill-oandi tioncd stock was always a barrier to be-lief in its purely dietetic origin.

It is now about 50 years since the parasite was first recognised by Pcllender and Davarne in the blood of anthrax-stricken animals. A few years later it was also found to infest tho blood of man when suffering from the same affection, -but it was not then known to be tho actual cause of the malady. It was not, indeed, until nearly 30 years afterwards that Koch proved to den^oustration what Davaine abroad and Professor Wortley Axe in England had clearly foreshadowed— viz., that the bacillus anthraci3 was the specific contagion of the di=ease. In 1376 Professor Simonde embodied in his report to the Royal Agricultural Sooiei-v of Eiipland a series, of experiments which Professor Wortley Axe had performed on rabbits, guinea pigs, and other creatures, the results of which showed that when the blood of animals afflicted with the di&ea=e was inoculated into healthy stock?, death f rotn anthrax quickly followed ; but what *was even more important than this, the blood of these victims of experiment invariably contained tho bacillus anthracis, and was as potent for evil as that originally emploj-ed. The effect of these experiments wa3 not only to demonstrate the infective character of the blood of anthrax animals, but to establish a connection between this blood parasite and the disease. Koch not only recognised this connection, but proved beyond doubt a ca=ual relation.

In an ossay on the anthrax question Profodcor Axe says: "The organism of anthrax, when viewed by high powers of the microscope, 13 seen as a minute rod-shaped body, varying somewhat in length and width, depending upon the species of animal in which it is found and the conditions under which it grows. In the guinea pig it is comparatively broad, while in the rabbit is is very thin. As a remit of bacterial research in various countries, a largo amount of information has been accumulated, not only as to its form and size, but also in respect of its life history*. Success in thi3 latter ha 3 been mainly clue, to the brilliant researches of Pasteur, by winch we have been able to cultivate the parasite outtfi"cle the body and to watch e\ery stage of its growth, development, and multiplication under a variety of conditions." The- anthrax bacillus, like all the- lower fungi, possesses mar\el!ous powers of reproduction, so much so that it is impo-sible to coneeue, much lesa to estimate, the vast numbers of this tiny miciohc which may come into existcnod in a fow hours after once a email number have gained access to the blood of a susceptible animal. This rapid multiplication is effected by a ourely vegetative process, in which the little rods, after quickly increasing in length, break off into short pieces, each freeing itself from the others, and becoming a separate plant or organism — an inditidual posseting all the attributes of its parent. As. such it commences at once to repeat this act of erowth and division, and this is continued from one generalion to another, until in a few hours the blood literally swarms with them. The vessels now choke and broak, and the blood, deprived of its ovyeen, and poisoned by the products of bacillarv activity, becomes stagnant nnd useless With the death of the animal the parasites cease to multiply, and if the infested carcase be not cut, all of them will die, and disintegrate as putrefaction proceeds, and in a few days the flesh will lose its virulence. In this instance the authrax parasite has killed its host, and brought about its own destruction. For when the latter ceased to breathe, the former was deprived of oxygen, and, thus enfeebled, became the victim of the of putrefaction.

"If instead," Professor Axe writes," of the carcase remaining intact, it in cut or bkinned or opened while the bacilli are still alive, a different order of events ensues. Here, owing to a free supply of oxygen having been admitted to the bleeding parts, reproduction not only continues after death, but is effected in quite a different manner. Instead of the simple method of multiplication by elongation and dnision, Uk 1 organism continues to grow to considerable length, and proceeds to form seeds or spores in its interior. These, sooner or later, i escape hko peas from a pod, and, like th««in. form storting points for the growth of fresh organisms This difference in the behaviour of the organism of anthrax under the conditioHs stated arises from the fact that seed formation in them can only take place when exposed to atmospheric air. So long as they are confined to the blood vessels, where air is not acce->tsiblp, «i long do they fail to form seeds or spores. But it must be remembered that although atmospheric air is necessary to seed format lan by the bacilli, it is not necessary to the development of bacilli from the seeds, for it is found when the latter aie inoculated, or enter by other means into a susceptible animal, they speedily develop into anthrax rods. The powers of resistance of these rods and seeds pbow a marked difference. Conditions which speedily destroy the one do not "impair the■wtalitv of th«* other. The rods die when oxposed to boiling water for a few seconds, but fie scedj live after boiling for several lnniutes. A solution of carbolic acid, whioh will destroy the rods in two minutes, fails to destroy the seeds ilia a week. Moreover, tho superior vitality of these deadly spores enables them to withstand both boiling and freezing, neither of whioh deprives them of their virulence. This stubborn resistance of the anthrax germ to physical and chemical forces specially fits it for the outjgtie. life it

is destined to lead and serves to* explain its abiding presence in and the danger which— attaches to infected pastures.

"What becomes of thesa spores while in the soil depends very much on the conditions in which they are placed. They may be taken up by one or another of our farm animals with the herbage, and set up a new focus of disease, or they may abide in tho soil, and under suitable conditions of temperature and food develop into rods, and these, again, germinate and throw off seeds, by which the soil becomes further contamii nated. The danger, therefore, of introducing the germ's of this disease into the soil! is not only that they may be as such consumed by farm animals, bufc that, like weeds» they may also reproduce their kind, and] so keep up a state of permanent infection. Hitherto the propagation of infection has been considered as occurring only from the dead carcase. It has, however, already been pointed out that one of the results of crowdtig of blood vessels with the bacillus which occurs in the course of the disease is to cause them to break. Should chis occur iv the vessels of the bowels or bladder, free escape of germ-laden blood may tace place with tho excrement and the \irine while tho animal is still alive. These bowel discharges from the sick are a frequent and a fruitful 1 source of soil contamination, and call for.speclal .attention in regard to measures of prevention."

No statistics have yet been compiled' as to the relation of anthrax prevalence to geological formation, but Professor Axe believes that the distribution of the disease over the United Kingdom is universal. During the 3 past six years it has occurred once or oftener in every county in England, in. 22 counties of Scotland, and in three counties of Wales. It may therefore bo concluded that, to a/ greater or less extent, all description"! of soil have at one time or another received) and transmitted anthrax infection. This, however, throws no light on the important question as to the nature of the soil most productive of anthrax, or. better, the soil which most favours the reproduction ai\d preservation of the organisms. A glance at the table compiled by the Board of Agriculture shows a rery considerable variation in the incidence of the disease on different counties, on Hie same county in different years, and in different parts of the seru& county. In no less than 21 counties it has become permanently established— i.e., has' been reported to have reappeared every year since the disease was scheduled. In six counties it has appeared five years out <if six, in seven counties four years, iv one three, in two counties twice, and in two once.

It is impossible to say at present in wl>afe relation, if any, these fact.* sfand to geological formation ; bufc the question is of the highest importance, and. being on© capable of solution, should receive an answer. Tfe is clearly the case tha 1 ; for s=ome re»=-;n or other the prevalence of anthrax in diffeivnfe counties, both in point of time and number, is singularly unequal, in raanv confirming* year after year, in others recurring only afc long intervals^ while in some it is entirely absent. Then .in regard to the number of outbreaks the same diversity is found. In one county they are of rare occurrence, while in the next adjoining they are repeated again and again at short intervals from year to year without abatement. "This* discrepancy of prevalence is one of the" most remarkable features of the affection, and if we cannot precisely indicate the measure of geological influence in its induction, observation has at least asaured ua of tlie> fact that such influence is a factor in the question. In this connection it ia common knowledge that anthrax is seldom present on light, thin, porous soil, and especially when occurring on chalk, while on the strong, rich loam and clays of our river valleys ifc is especially" prevalent. Lowlands are mcre> pregnant of anthrax than are uplande; and! whetlier it be one or the other, dampness is certainly a favouring condition. Seasonable influences are unquestionably concerned in the propagation of anthrax ; for although the disease prevails throughout the year, ifc is by no means uniformly distributed throughout the months comprised in it." The mistakes frequently made, even by professional men. in the identification of the specific germs of distinct diseases to which live stock are subject suggest the advisability of quoting hei-e the dicta of one of the most famous bacteriologists of the day, Professor Crookshank, who says: "It is not sufficient to discover 'rods' in the blood of animals to be .convinced of the nature of the disease. We must be certain. There are for t v he inpxoeripneed vpnr deo^T'tive 'rods,' the bacilli of malignant oedema. These rods may occur in the blood wlien in a» state of decomposition. While the long, curved forms are readily recognised, the short forms are extremely deceptive. Further, if guine-a pigs be inoculated in these eases they die. and the fact of their death, together with the presence of rods, may bo regarded as additional proof of the disease beiug anthrax. As a rule, the bacillus of malignant oedema produce* death in 24- • hours, the anthrax bacillus in 36 to 48. The spleen in malignant ffidema is not, as a rule, enlarged, while it is so in anthrax. In malignant oedema the bacilli, if examined 1 some hours after death, may be found in all the organs."