INOCULATION FOR TICK
IMPORTANT INTERVIEW WITH MR.
A GLEAM OP LIGHT AND COMFORT.
HOW CATTLE MAY BE MADE IMMUNE
In a recent interview with a representa- tive of the Rockhampton " Record," Mr. C. J. Pound, Government Bacteriologist, sup- plied the following important information concerning recent experiments :
A UNIQUE EXPERIMENT.
Asked to supply information as to . tho Mundoolan experiments, Mr. Pound said that six months ago two steers from Inker- mann station, in North Queensland, were dipped, cleansed, and shipped to Brisbane. There, while uuder his charge, they had entirely recovered, and become quite free from both ticks and tick fever. About four months after their arrival he had taken blood from these steers and injected it into two calves at Indooroopilly, both of which afterwards suffered from very slight fever, so slight, indeed, that It could only be de- tected by taking their temperature with the clinical thermometer. The results were noted day by day, the temperature being taken twice dally. It waa found that the maximum temperature occurred on the fourteenth day, after which it gradually de- clined to normal on the twenty-first day. This test showed the importance of the clln'lcal examination, as cattle were often suffering from fever long before it could be detected by the eye, or hy any change in their habits or appearance. Hence the conclusion that, without the aid of the clinical thermometer, and the most careful and regular observation of cattle under close supervision, experiments must be com partively valueless.
NO POISON IN BLOOD OP TICK-FEVER
Did you malee any further experiments with the calves, Mr. Pound ?
Yes, and what I conceive to be a most important one. Wo took one of the inocu- lated calves and one of the Inkermann steers to Mr. Colllns's Mundoolan station, on the Logan River. There forty-one cattle of frorn 2 to 3 years of age, and all in good condition and perfectly healthy, had -been made available to work upon. Of these, thirty were inoculated with varying doses of blood from the Inkermann steer-that is, from the máximum of 8 c.c.m. to 1 c.i.m. -in different parts of the various animals one, for example, In the jugular vein, an- other in the tail, and another behind the shoulder. The doses, as already said, were varied in every case, and each animal being branded with a number, careftil records were made of temperature morning and even'ing, and of other symptorhs. Then five head of cattle were Inoculated with blood from the calf which had, as already stated, been previously inoculated from the steer. The remaining six were Inoculated . with blood from the steer after passing the serum through the Pasteur filter-the object in filtering being to absolutely exclude all germs, and inject the poison (so-called) minus the germs.. \ The lesult of the ex- periment was that' tèëre was apparently no poison in the blood','tHnd that inoculation with pasteurised serum from a diseased animal would yield no result, in conse- quence of the mechanical breaking-down of the blood cells by filtering.
DETAILS OF THE GREAT EXPERIMENT.
Invited to specify precisely how his ex- periment at Mundoolan waa ca-rried out, Mr. Pound said that he made a clinical examination of the temperature ot each animal! every morning and evening, and recorded the result .In detail in the book (produced). On examination, our roi.re sentative found that.a folio was devoted to each of the forty-one animals, every one having its own specific number, with the " dose" injected, the part of the body Into ?which the Injection was made, and t*e temperature recorded with the utmost ex-* actness every morning and evening during the continuance of the fever-three weelo». Mr. Pound hero remarked that too much care could not "bo taken 'In the use of 'the thermometer. For example, if the cattle ?were rushed into the yard or agitated in any way the value 'of the t<~t would be impaired by the access of animal heat thus created. Then the time occupied In test- ing the temperature l of fOrty-one anihials twice a day was considerable. The ther-
mometer (bad to remain in the rectum of each beast for three minutes, and there was of course time lost in going from one bea-t to another, and in making the careful re- cord. He lund "been greatly iimpreösod with the Importance of the utmost exacti- tude in this matter, hecause if the test were in any way imperfect, or the record inexact, the oasis of the conclusions yielded by the experiment was of little value. Ho had found great difficulty in ascertaining the true value of experiments made on cattle In America and elsewhere, by reason' of the want of detail in the records. In fact, so far as he could ascertain, no ex- periments had been made elsewhere with tihe care -and minuteness with which he had striven to conduct the experiments at Mun- doolan. By permission of Mr. Pound no reproduce a folio of his record book, show- ing a typical case, as follows :
Temperatures (night and anornibig) for three weeks of a two-year-old steer which had been Inoculated in the jugular vein -with 5 c.c. of blood taken from a healthy animal which six months previously had
been tick infested :
. ' 103
/ ' 6
. .104.8 13
very ntmmeraujs, in the Mood) .
freely and completely recovered from fever.
(It will he noticed that from the four- teenth day there was a continuous decline In temperature, until on the eighteenth day it became sub-nomal.)
RESULTS OF THE EXPERIMENT.
As to the results of the Mundoolan ex- periment after the fever had subsided, Mr.
Pound said :
(1) The six beasts inoculated with the Pas-
teur filtered serum 'showed no change in temperatura throughout the experi- ments. In other words they remained perfectly healthy.
(2) Six beasts inoculated with serum from
either the steer or the calf had slight
fever as indicated by the thermometer, j
but so slight as to be not otherwise ob-
(3) Twenty-nine beasts, inoculated with
.serum as in the last case, all had distinct
tick fever as shown by the thermometer, but only a few so as to be visible to the
(4) Several had redwater-or, rather, black-
TICK FEVER WITHOUT TICKS.
Tlie experiment, therefore, showed- that blood from animals that had suffered and recovered from' tick fever-in the case of the calf produced secondarily by inocula- tion without the presence of ticks-had produced in a nunaber of previously healthy stock the typical disease of tick fever in the absence of ticks. Moreover, the steers from which the blood serum was taken had recovered six months before the blood was so taken. This proves that the gorm once impregnated in the blood of a bovine ani- mal has its permanent home there, and that such blood in a certain percentage of cases Is capable of reproducing the disease. Of course there are In every herd Insusceptible cattle which escape tick fever when the tick is present, and also aro not susceptible when it Is absent. Ho could not explain why some cattle are insusceptible,, and could only; speak of the facts which had
come under his own observation. Of the Mundoolan cattle which wero in high fever (continued Mr. Pound).four died, but the rest all recovered, although some of them were very emaciated, but when he last saw them they were ablo to ruminate, and evi- dently were picking up condition. He added that this wa3, he believed, the largest experiment ever made-that is, with the greatest number of beasts-anywhere, not .excluding America, and he considered the .results highly gratifying and reassuring. When here twelve months ago with Mr. Bruce, the New South Wales Chief Inspec- tor of Stock, he advised Inoculation as a practical means of protection against tick
FEVER PRODUCIBLE BY A SINGLE
Another important fact in connection with the experiment Is that the first beast to die at Mundoolan was ono that had been inocu- lated with the minimum quantity of blood (1 c. c.)' from the Inkermann (steer. From this and other observations he had con- cluded that a single tiojc getting on a bul- lock might produce tick fever, with red- water, the consequence of the fever.
POST-MORTEM APPEARANCE OF THE
Asked to describe the post-mortem ap- pearance of the cattlo that died under the Mundoolan experiment,-Mr. Pound said tha they wero all typical cases. The organs of,, ono animal presented the following appear-* ance :-Urine in bladder dark and claret coloured ; kidneys almost black ; spleen three times the normal size ; spleen on .being cut into had the appearance of black currant jam ; liver considerably enlarged, and of a yellow hue ; and gall bladder dis- tended with dark greenish-brown granular contents. There was very little blood in the veins, although the animal had been In splendid condition. After death Its flesh presented the anaemic appearance of young
ACCURATE DIAGNOSIS POSSIBLE.
Further, continued Mr. Pound, on the fourteenth day after inoculation at Mun- doolan, and when only a few showed symp- toms of fever, tho blood of every animal was m'icroscoplcally examined. In every ease, except thoso inoculated -with the filtered serum, the micro-organisms of tick fever were found in the blood. So that, without knowing the history of the animals, he (Mr. Pound) was able to'state, as the result of microscopical examination, the exact state of the disease when the blood was taken, and to determine whether the' attack was in (1) the preliminary, (2) the acute, or (3) the convalescent stage. He could also determine whether or not any beast would recover from the attaclc.
To -which our representative observed that he presumed this knowledge would be useful as enabling a stockowner to isolate and de- stroy the animals which were shown to be beyond recovery.
SPECIAL IMMUNITY OF THE INOCU-
But, continued Mr. Pound, the Mundoolan experiment was of special value In another respect. Tho first anlimal that died (be- fore referred to) was a cow in calf. On examination it was found that the blood of the foetal calf-which was not, more than 12in. in size from nose to tail-contained micro-organisms of tick fever in large num- bers. From this he thought it might be assumed that the organisms are trads mitted to the embryo before birth, and that the young animal becomes immune. This feature of the experiment is very Important as indicating that the means may thus be provided of -inoculating the progeny of healthy cattle in places outside tick-Infested areas. He thought that his experiment in- dicated why, speaking generally, calves
bon! in tick-Infested country would be im-
mune from the disease. And as cattle were less susceptible in early life, be thought that by inoculating calves with serum containing the micro-organism they would be rendered practically immune. Not so with the adult animal, however. An adult beast might have tick fever twice and recover, and have it a third time and die. It had been said that calves as well as their mothers had died from tick fever, but he thought that <the calves bad died from starvation, and in this opinion he was sup- ported by some practical men,
AGREEMENT WITH AMERICAN
The result of this experiment with the blood of the Inkermann steer, continued Mr. Pound, is a confirmation of what had been done at Washington. There' a cow was brought from the tick-infested district of South Carolina six years ago, and had recovered from the fever. But it has been found that the micro-organism is still In her blood, and that Texas fever can always be produced in another bovine animal by taking a liUIe blood from the cow and injecting it into a susceptible animal.
Then, said our representative, I under- stand the ascertained result of the ííundoo lan experiment to be, as far as it goes, that tick fever may be produced without ticks, and that young calves may be ren- dered immune by inoculation with the-blood of such animals. Also, -that animals so rendered immune will transit such immu- nity to their progeny. But is there no dan- ger of contagion from such animals if placed among healthy Mock ?
. No, replied Mr. Pound, the cattle in which I produced tick fever at Mundoolan were running with the dairy cattle at the station at the time. There is no fear of contagion without the tick, unless, of. course, by inoculation with the blood. 1 am convinced that among the grazing farms of the Upper Hunter River, there are hundreds of cattle which have been taken from the tick-in- fested districts of Queensland, and the blood of which would produce tick fever in healthy cattle by inoculation in the same manner as we produced it ' at Mundoolan. The germ, I repeat, has a permanent home in the blood of cattle which have recovered from tick fever, and It is protective against fever in those animals. To what extent it is protective has yet to be demonstrated ; but tho progeny of such animals, or of animals inoculated when young calves, are, in my opinion, absolutely immune, and if placed in an infested district would not be susceptible lo tick fever. In this way I think New South Wales may, by inoculation of her young stock, be protected from the fever and its deadly consequence, redwater.
And in Queensland, although there will be j
a percentage of Inoculated adult cattle still susceptible, their progeny will be immune.
EXPERIMENT CONTINUED AT NORTH
That is very encouraging, remarked our representative, and if borne out In practice will greatly mitigate the terror felt of the spread of the tick pest.
Yes, Mr. Pound replied, but it must be distinctly understood that further experi- ments aro necessary. For example, I am arranging to bring some of these Mundoolan inoculated cattle to North Rockhampton, as a continuation of the experiment there, to ascertain whether or not they are immune. My Impression Is that they will be more or less susceptible, and that some of them may again have tick fever, and perhaps die. But the experiment will bo an instructive pno, in any case. And here let lue^-mention that I preferred taking cattle from the Logan because it was a district of which there could not be the slightest suspicion of infection. Blood taken from an animal depastured in a suspected district might contain the micro-organism of tick although to all appearance the animal was perfectly healthy. There are, no doubt, clean cattle in the Central district, but in 'an experi- ment of this kind it waa well to be per- fectly sure. Besides, it might occupy months to ascertain positively whether any local cattle were clean or not. Thus, by bringing these Mundoolan cattle time would be saved. Mr. Barnes's services will be very useful in this extended experiment, for in taking the temperature night and morning and keeping the cattle under con- stant observation he will find his spare time well occupied. With these Mundoolan animals, let me add, there must be " con- trol" animals brought up as a test.
TICKS "WILL MATURE ON HORSES.
Asked whether he intended to continue further experiments, Mr. Pound said he was most desirous of doing so, but he found some difficulty In getting the necessary authority for the purpose. For example, it was only after continued representation of the importance of the question that he obtained two cows and placed them on Peel Island for the purpose of ascertaining whether ticks o£ which a horse had been the host would give tick fever to cattle. He got fifty or sixty young ticks, the progeny of a cattle tick which matured on a horse, and placed them on the udder of one of these cows, leaving the other to serve as a " control" animal. The cow on which the ticks were placed soon developed fever, and ultimately recovered, but was in an emaciated state. Mr. Pound then produced two photographs, one of the " control" cow, which was per- fectly healthy and sleek-looking, and the other of the cow after the fever, with drooping head and a general woe-begone appearance. This, he thought, established the fact that ticks carried by horses con- tained the germ of fever, but the horse was not a congenial host, . and very few ticks came to maturity upon it. Still, there could be no question that ticks might be spread throughout the country by horses, and even by wild animals and birds.
CANNOT EXPRESS OPINION ON
Then you are doubtful whether the
quarantine line will protect the Southern , part of the colony from the tick, said our representative.
With a shrug of the shoulders Mr. Pound indicated that he preferred not to express an opinion upon that burning question. But he admitted that an inviolable quaran- tine cordon was scarcely within the range of possibility. « '