CONTAGIOUS MAMMITIS

Manawatu Herald, Volume XLVII, Issue 2961, 12 November 1925, Page 3

CONTAGIOUS MAMMITIS

BACTERIOLOGIST’S REMARKS!

As the interim report issued by the Agricultural Department regarding the efficacy of the vaccine, with which cows are being inoculated, with the object of making them immune from contagious mamitis infeeton, was inclined to sugest that the vaccine was of no t use, Mr. J. G. Smith, bacteriologist to the Waikato Hospital, who prepared the vaccine, staffed l in an interview last month, says the Auckland “Herald,” that it was only fair to anyone who had taken an interest in its use to lay a few facts before the farmers. Mr. Smith said, as he pointed out to the officers of the Agricultural Department, the experiments carried out by them were of little value, as they only demonstrated one point, that the use of vaccine would not protect against artificial infection, which was a vastly different thing from natural infection. The vaccine for mammitis was prepared on similar lines to anti-typhoid vaccine, the value of which .was undoubted. Yet a 'person who was inoculated against typhoid fever could not swallow the germs and hope to escape infection. Mr. Smith said he had consulted the highest authorities who agreed on this point. He quoted from Kolmer’s “Infection Immunity and Specific Therapy,” the greatest book written upon the subject,' in which is stated :—“Duration and degree of typhoid immunity: It should be emphasised that immunity following typhoid inoculation is not absolute and an immunised person cannot afford to neglect ordinary precautions against infection. A lowered state of body health or a large dose of infectious material may at any time result in infection.” No one could claim that injecting infected material up the teat canal of a cow, as was done by the department could be considered an ordinary precaution, said Mr. Smith. It was a well-known fact that some animals were naturally immune, and would never contract contagious mammitis by ordinary means; the control cows of the department’s test might easily he in this category, as immunity was an unknown factor and differed in every individual, whether produced by inoculation or by natural means. Therefore, results obtained over a few cows artificially infected were not sufficient to undermine the confidence of people who believed in the treatment of contagious mammitis by vaccines. As far as his own experiments were concerned, Mr. Smith, said these were conducted over several hundreds of cows and herds that were inoculated three years ago and were badly infected at the time. These cows were still free from the disease. He had demonstrated in the laboratory the effect of the blood serum of an inoculated cow upon the germ of the disease and produced a similar effect as that observed when the blood serum from a patient inoculated against typhoid was similarly tested with the typhoid bacillus.

Regarding the use of vaccine for contagious mammitis in other countries, Mr. Smith said that, in 1922, the Director of the Australian Commonwealth Serum Laboratories, Dr. Penfold, a noted scientist, and late assistant-director of the Lister .Institute London, issued a circular to veterinary surgeons, advocating the use of vaccine for contagious mammitis. One point in the Agricultural Department’s report Mr. Smith said he wished to draw attention to was the statement concerning the danger in “resting under false security.” He pointed out that where the vaccine was used the farmers were expressly told that they must not neglect ordinary precautions. He also pointed out that a vaccine would only have an effect upon the particular infecting organism from which the vaccine was prepared. -He commenced experimenting on cows with vaccine prepared from organisms isolated from human beings and carried on with the work of contagious mammitis vaccine through representations from farmers whose cows had great relief from the vaccine, and he was more than ever convinced that the persistent use of vaccine was the only means of combating contagious mammitis, which was economically the worst form of udder trouble.