Research into certain animal diseases / by T. Dalling, H.R. Allen and J.H. Mason.

  • Dalling, Thomas.
Date:
[1925?]
Catalogue details

Licence: In copyright

Credit: Research into certain animal diseases / by T. Dalling, H.R. Allen and J.H. Mason. Source: Wellcome Collection.

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    Reprinted from “ The Veterinary RecordJuly 11 th, 1925. I(&lp Research into Certain Animal Diseases.* By T. Dalling, H. R. Allen and J. H. Mason, Wellcome Physiological Research Laboratories, Beckenham. Swine Erysipelas. The method adopted in the production of an anti¬ swine erysipelas serum is to inject horses intravenously with dead cultures of B. erysipelatis suis, followed later by living cultures. The testing of its potency can be carried out with mice (the official German method), though we have, on the whole, got more consistent results with pigeons. Table I. gives the results of testing on mice the protective power of some serum we have recently made. In the experiment a standard culture of the organism on agar was used which, when washed off and diluted suitably with normal saline solution, killed mice regularly in five days after the intravenous injection of 1 c.c. Table 2 is a comparison of serum produced by one of our horses with two Continental official samples. In the experiments indicated, pigeons were used; the culture and serum were mixed and stood for an hour at room temperature before being injected intramuscularly. Readings were taken daily up to four days. This test is the one widely used on the Continent ; apparently the results obtained by this method in which the culture and serum are mixed and in which the bactericidal properties are given full play, gives results consistent with those obtained when the serum and culture are injected separately into the animal. (See Table I.). TABLE I. Serum. Dose. ; Result. Horse A. 0*1 c.c. L L 0*075 c.c. L L 0*05 c.c. L L 0*025 c.c. D4 D4 0*01 c.c. D2 D2 N.H.S. 0*1 c.c. D2 D2 No serum D2 D2 L = Lived. D5 D4 = 1 mouse of pair died 5th day and the other mouse 4th day. Serum intraperitoneally and same dose of culture intra¬ venously given 24 hours later to all mice. * Presented to the Central Veterinary Society at Langley Court, Beckenham, on June 11th 1925. TABLE 2. Serum. Dose Serum. Culture. Result. X 0*3 c.c. 500 M.L.D. L 0*2 c.c. 99 L 0*1 c.c. 99 D4 Y 0*3 c.c. 99 L 0*2 c.c. 99 D3 0*1 c.c. 99 D3 W.P.R.L. 0*3 c.c. 9 9 L 0*2 c.c. 99 L 0*1 c.c. 99 D4 No serum — 99 D3 — 100 M.L.D. D4 10 M.L.D. D4 Pigeons used. Serum and culture mixed and injected intramuscularly. L = Lived. D4 =Pigeon died 4th day. The Testing of B. Bronchisepticus Serum and Vaccine. Because of the relative frequency with which B. bronchisepticus can be isolated during some out¬ breaks of canine distemper, in pure culture from the tissues of affected dogs, serum and vaccines made from strains of this organism have been used for curative and prophylactic purposes. Success has been claimed by some veterinary surgeons from their use in some outbreaks of distemper. B. bronchisepticus Serum. The serum is prepared by injecting horses with increasing doses of dead or living cultures of the organism—several strains being used. Guinea-pigs are used in testing the protective value of such serum. Table 3 represents an experiment to ascertain the smallest dose of serum protecting against a certain lethal dose of culture. To make certain that we were not testing merely for bactericidal properties in vitro, we injected serum in another experiment 24 hours before the culture. Table 4 seems to show that the serum was really anti-bacterial in the body. Anti-bronchisepticus Vaccine. Tables 5, 6, 7 show the evolution of the method now recommended for vaccinating dogs against B. bronchisepticus infection, i.e.} two doses of a killed vaccine followed by one dose of living culture. Table 5 shows that a high degree of protection was obtained after one dose of killed culture, five out of six animals surviving when tested a month later. Table 6 in¬ dicates that two doses of killed culture acted similarly while Table 7 sets forth the result got by adding a dose of a living culture; complete protection is evident fourteen days after the last dose of vaccine.