Veterinary biological products : their standardisation and application / by T. Dalling, H.R. Allen, and J.H. Mason.

  • Dalling, Thomas.
Date:
[1926?]
Catalogue details

Licence: In copyright

Credit: Veterinary biological products : their standardisation and application / by T. Dalling, H.R. Allen, and J.H. Mason. Source: Wellcome Collection.

    1/8
    Reprinted from “ The Veterinary Record ” January 23rd, 1926. Veterinary Biological Products—Their Standardisation and Application.* By T. Dalling, M.R.C.V.S., H. R. Allen, M.R.C.V.S. and J. H. Mason, M.R.C.V.S., Wellcome Physiological Research Laboratories, Beckenham, Kent. This paper was written for presentation to the North of England Division of the N.V.M.A., because, in choosing a subject on which to write, we have been guided by the facts that we could best give information on animal diseases which we have been investigating recently, and that all veterinary practitioners might not have full knowledge of the degree of accuracy with which veterinary biological products can be standardised. Our intention is to deal especially with biological products in use for the prevention, cure or diagnosis of blackleg in cattle and sheep, braxy in sheep, B. bronchisepticus infection in dogs, swine erysipelas, leptospiral canine jaundice, tetanus and tuberculosis. On a given batch many tests are usually made ; we show only typical ones taken from our records. Blackleg in Cattle and Sheep. Because it has been shown that Vibrion septique is found alone or in association with B. chauvcei in some cases of clinical blackleg in cattle and sheep, products have been devised which, on subcutaneous injection, will confer immunity against infections of both organisms.. This product consists of equal quantities of B. chauvcei filtrate which, in our experi¬ ence, has proved atoxic for all animals even when in¬ jected intravenously in large amounts, and a toxin- antitoxin mixture of Vibrion septique, which is also atoxic, although Vibrion septique toxin alone is highly pathogenic. Many experiments have been done to show that this product does confer immunity {e.g., Allen and Bosworth, Vet. Journal, Vol. 80, No. 9) in which guinea-pigs and sheep have been used. Tables I to IV illustrate results obtained by us in work on a recently made batch of this product. Table I shows that a potent Vibrion septique toxin had been produced of which 0-001 c.c., injected intravenously, was sufficient to kill a mouse. The titration of this toxin against Vibrion septique antitoxin was carried out as indicated in Table II, which shows that the toxin used was a specific one and that it was necessary to add 50 c.c. antitoxin per litre to neutralise the toxin. Table III indicates that this batch of product conferred immunity against B. chauvcei infection in guinea-pigs, and in Table IV are results of similar experiments in which Vibrion^septique toxin was used to test the immunity. It may be of interest to know that sheep injected with a similarly-made product have been shown to develop an immunity against B. chauvcei and Vibrion septique infections, which conferred full protection against virulent culture injected eighteen months later. It is fairly certain that this immunity lasts for many years and probably for life. Braxy in Sheep. We have already shown that this chauvoei-septique prophylactic confers immunity against naturally occurring braxy (see F. R., No. 28, Vol. 5). Since these results were published, we have had information on a small test carried out on sheep in Wales by Mr. N. Bisset, M.R.C.V.S., University College, Cardiff. One hundred young sheep were injected during the late autumn of 1924 with the preventive, and one hundred control sheep were kept under exactly similar conditions. The results at the end of the braxy I season, 1924-25 were, that of the one hundred control sheep, eighteen had died of braxy, while of the one hundred inoculated ones, only one died. Table I. Titration of Vibrion septique Toxin. Mice used—injections intravenously. Toxin. Result. 0-25 c.c. to 0*01 c.c. ... ... ... ... All died. 0*005 c.c. ... ... ... ... ... D. 0*001 c.c. ... ... ... ... ... D. 0*0005 c.c. ... ... ... ... ... L. D = died. L = lived. Table II. Titration of Vibrion septique Anti-Toxin. Mice used.—injections intravenously. Toxin. Serum. Result. 0*01 c.c. ... 0*001 c.c. ... L. 0*02 c.c. ... 0*001 c.c. ... L. 0*03 c.c. ... 0*001 c.c. ... D. 0*04 c.c. ... 0*001 c.c. ... D. Neutral point — 0*02 toxin = 0*001 c.c. serum. Toxin and serum mixed and stood one hour before injecting mice intravenously. L. = lived. D. = died. Table III. Protective value of B. chauvcei Filtrate. Four guinea-pigs injected with mixture containing 50 per cent. B. chauvcei filtrate. Two doses given at interval of eleven days. Test done of living culture five weeks later intra¬ muscularly. •Paper read before the North of England Division of the N.V.M.A. by Mr. T. Dalling, December 5th, 1925.