Contagious Abortion of Cows

Part 1

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UNIVERSITY OF ILLINOIS

Agricultural Experiment Station

BULLETIN NO. 152

CONTAGIOUS ABORTION OF COWS

BY W. J. MACNEAL IN COÖPERATION WITH HERBERT W. MUMFORD

URBANA, ILLINOIS, NOVEMBER, 1911

SUMMARY OF BULLETIN NO. 152

1. The existence of a specific contagious disease causing abortion in cows has been recognized for a long time, and it is certain that the disease known abroad as infectious or contagious abortion is also prevalent in the United States.

2. The infectious agent is a bacterium first described by the Danish investigators, Bang and Stribolt. This microörganism has been isolated from aborting cows in various European countries and in the United States.

3. Bacteriological examination of afterbirths from aborting cows at this Station revealed the presence of this germ.

4. To eradicate the disease from a herd, the affected cows should be isolated, and their genital passages cleansed once or twice daily with an antiseptic solution until all discharge has ceased, when they may be returned to the herd; all infectious material (afterbirth and discharges) should be burned; infected stalls should be cleaned and disinfected; the sheath of the herd bull should be cleansed with a disinfectant solution before and after service, and a separate, clean bull should be used for heifers and clean cows.

CONTAGIOUS ABORTION OF COWS

BY W. J. MACNEAL, ASSISTANT CHIEF IN BACTERIOLOGY, IN COÖPERATION WITH HERBERT W. MUMFORD, CHIEF IN ANIMAL HUSBANDRY

INTRODUCTION

The premature discharge of the products of conception from the uterus is a not infrequent occurrence among domestic animals, and doubtless various factors may from time to time operate in its causation. For a long time, however, practical husbandmen have recognized an epizoötic or contagious kind of abortion, a definite transmissible disease in which the loss of the fetus is the most prominent characteristic. The transmissibility of contagious abortion of cows appears to have been demonstrated experimentally for the first time by Brauer. Experimental transmission has been performed by a number of investigators subsequently, the work of Nocard (1886) furnishing conclusive evidence upon this point.

It is certain that a disease, or possibly more than one disease, of this nature is a source of serious loss to the live stock industry in the United States, and there can no longer be any doubt that a considerable part of this loss is due to the definite specific disease prevalent on the continent of Europe and in England, and known as Contagious, Infectious, or Epizoötic Abortion. The purpose of this bulletin is the brief presentation of some of the facts concerning the cause, prevention and restriction of this disease, which have been established by modern investigation, for the information of men engaged in live stock production.

BACTERIOLOGICAL INVESTIGATIONS ELSEWHERE

Nocard carried out the first extensive bacteriological investigation of contagious abortion. In microscopic preparations of the diseased placenta he was able to recognize numerous short bacilli and micrococci. These were also found in the amniotic fluid. He obtained pure cultures of these two organisms, but failed to induce abortion upon inoculating these cultures into other animals. Neither of the germs obtained in culture could therefore be regarded as the causative agent in the disease.

In 1895 Bang and Stribolt undertook the investigation of this disease, and their results are now generally regarded as the most important of all the contributions to the study of this subject. A cow showing all the symptoms of impending abortion was purchased and slaughtered. The unopened uterus was removed to the laboratory where it was opened with special precautions to avoid all contamination. An abundant, grayish yellow, odorless exudate was found between the ovum and the inner wall of the uterus. Upon standing this exudate separated into two layers, a reddish yellow serum above, and a grayish yellow partly solid layer below. In microscopic preparations of this exudate, stained with Loeffler's methylene blue, numerous very small bacilli were found, apparently in pure culture, some of them lying free, but large numbers of them crowded together inside cells. These latter appeared at first to be micrococci, but more careful examination proved them to be really short rods. Bang and Stribolt were able to cultivate this organism in tubes of a gelatin-agar-serum medium, the germ developing only in a particular zone beginning about 5 mm. beneath the surface of the medium and extending downward 10 to 15 mm. After considerable work with cultures, they concluded that the bacillus is neither an aerobe nor an anaerobe, in the ordinary sense, but exhibits a very peculiar behavior in respect to oxygen, requiring for its development a partial pressure of oxygen somewhat less than that present in the atmosphere. They were unable to obtain growth of the germ in the presence of the ordinary atmosphere, nor in the absence of oxygen (Pyrogallol method). Curiously enough, by placing their tube cultures in an atmosphere of pure oxygen, they obtained cultures developing in two zones, one near the top and the other near the bottom of the tube, indicating that there are two optima in the oxygen requirement of the organism. This very interesting character of the organism received great attention at their hands, but nevertheless Bang points out that typical development such as he has pictured was not always obtained, a number of factors seeming to cause variation in the position and extent of the developmental zones in these tube cultures. By exhausting the air above the medium in the tube, the growth was made to extend to the surface. In this way they were able to obtain growth of the bacillus on plates, but they did not work out a reliable plate method, preferring to employ the dilution tube cultures for separation in all their work. Bang and Stribolt subsequently examined pieces of placenta from a large number of cases of contagious abortion, and found the bacillus microscopically in practically all cases. Sometimes they were abundant, in other instances very scarce. Most of this material was badly contaminated, yet, from that sent in during the colder season they successfully isolated the bacillus in pure culture in a majority of the cases. In three fetuses the bacillus was found in the intestinal contents in pure culture; in one fetus it was isolated from the blood. Two cows with mummified fetus in utero were examined post mortem. These fetuses had been dead 9 months and 5 months respectively but the surrounding exudate still contained the abortion bacillus and pure cultures of it were obtained from each case. Uterine exudate kept in the refrigerator still contained living abortion bacilli after seven months.

Having found the same bacillus microscopically in a series of cases of abortion, and having obtained it in pure culture from a number of them, it now remained for Bang and Stribolt to produce the disease by inoculation of these cultures into healthy animals. Four pregnant cows were obtained without knowledge of their previous history. Two of them were inoculated by intravaginal application of pure cultures, and two by intravaginal application of pieces of afterbirth from aborting cows. No abortion resulted in any of the cows and at slaughter 19 to 29 days after inoculation, there was no evidence of the disease. This result was surprising, as Brauer had induced abortion by the second of the above-mentioned procedures in from 9 to 21 days, Lehnert in from 12 to 20 days, and Trinchera in 9 to 13 days. The authors thought that the animals may have been immune on account of a previous attack of the disease, or that possibly the interval between innoculation and slaughter (19 to 29 days) may have been too brief for the disease to have developed. For the next experiment two cows were purchased from a region where abortion was unknown. Pregnancy began January 14 and January 16, 1896. On April 14, a rich culture of the abortion bacillus was injected well up into the anterior end of the vaginal canal of each of these cows. The inoculation was repeated in the same way on May 23, and again on June 4. One cow aborted June 24, the fetus evidently having been dead some days. The abortion bacillus was isolated from the afterbirth. The other cow showed the signs of impending abortion on June 23, and was slaughtered on June 24. The condition inside the uterus resembled in every respect that observed in the cow from which the original culture had been isolated, and the bacillus was present in pure culture. In these cows the disease had appeared 10 weeks after the first inoculation. A third cow was inoculated by intravaginal application January 19, 1897, and subcutaneously March 6, in both instances with pure cultures of the bacillus. Premature delivery of a living calf occurred April 9, 80 days after the first inoculation. Abortion was also caused in sheep by intravaginal application and by intravenous injection of pure cultures. Inoculation by the latter method proved to be more certain in these animals, and the incubation period after intravenous injection was only 7 days in one case and 12 days in another. Intravenous inoculation of a mare resulted in a premature delivery after 28 days. In all these cases the bacillus was recovered from the afterbirth.

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