Ward J. MacNeal

“ When a fetus is aborted alive, as sometimes happens, it seldom survives long, and it is advisable to kill and destroy it, since it may excrete abundance of virulent material from its intestines if allowed to live. If, however, it be decided not to kill it, it should immediately be isolated. The walls of the stall and the floor should be washed or strewn thickly with caustic lime, or drenched freely with boiling water. The temperature necessary to kill the bacillus is not great, and this simple method of disinfection should prove efficacious. ”

“ 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. ”

“ 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. ”

“ The appearance of the colony is really a very characteristic feature of the organism and enables one to distinguish readily the colony of the abortion bacillus from other colonies on the serum-agar plates. ”

“ 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. ”

“ 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. ”

“ A final important test in identification is that of pathogenicity. Nowak induced abortion in pregnant guinea pigs with great regularity by subcutaneous, intraperitoneal, and intravenous injection of pure cultures of the abortion bacillus. So far, four pregnant guinea pigs have been inoculated subcutaneously with the pure cultures isolated by us, and the inoculation has been followed by premature evacuation of the uterus with death of the fetuses in 31⁄2, 8, 6, and 7 days respectively. In the first guinea pig the two fetuses were practically fully developed and covered with hair. ”

“ 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. ”

“ The behavior toward oxygen is another character upon which considerable reliance may be placed in the identification of strains recently isolated from the animal body. This is tested by transplanting the colonies from the serum-agar plates to two series of agar streak sub-cultures, of which one series is incubated in the atmospheric air and the other in the closed jar together with cultures of B. subtilis. Unless the growth under the latter condition is much better than the growth outside the jar, the culture may be discarded as one not belonging to this species. ”

“ Irrigation of the Genital Passages after Abortion.—With the act of abortion the greater part of the uterine exudate is immediately ejected. That some of it remains behind for a short period is certain, since we were able to demonstrate abortion bacilli in material obtained from the vagina of a heifer three days after she [Pg 540] had aborted. On the other hand, no abortion bacilli could be found in the uterus of another heifer a month after she had aborted. ”

“ In the United States contagious abortion is widespread, and has been recognized for a number of years by practical husbandmen as an important economic factor in animal industry. Epidemiological studies have recently been reported from Arizona and Connecticut. ”

“ Isolation of Animals as soon as they show Signs of Abortion.—The necessity for this measure is obvious, and its importance cannot be too much insisted on. An infected animal only becomes infective to others immediately before the act of abortion, and may remain so for some weeks afterwards. ”

“ They were able to produce the disease in cows by intravenous injection of natural virus and of active pure cultures, without a failure in eight experiments. By intravaginal application they caused the disease twice with cultures and three times with natural virus, but also failed to obtain any result in three trials with the natural virus. Subcutaneous inoculation was successful three times in five trials. By feeding they produced the disease three times in four trials. These authors consider ingestion to be an important mode of contracting contagious abortion in nature. ”

“ 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. ”

“ Eight were cases of premature delivery, and of these, six appeared clinically to be cases of contagious abortion. Placental tissue from two of these cases was examined by the Nowak plate method and a bacillus isolated, apparently identical with that isolated by Bang in Denmark and by Nowak in Austria.
The organism is a very small short rod, usually oval in shape, from 0.8μ to 2.0μ long by 0.7μ wide, practically always single, rarely in short threads of two to four cells. It is not motile, and does not form spores. ”

“ Altho the experience here has been rather fortunate and the results obtained seem to bear some relation to the employment of the measures deemed worthy by the British Committee, we hesitate to state that there was any necessary relation between them, because cattle men have observed somewhat similar improvement in herds without the use of any treatment at all. ”