Bacillary white diarrhœa of chicks (B.W.D.) / by T. Dalling, J.H. Mason and W.S. Gordon.

  • Dalling, Thomas.
Date:
[1927?]
Catalogue details

Licence: In copyright

Credit: Bacillary white diarrhœa of chicks (B.W.D.) / by T. Dalling, J.H. Mason and W.S. Gordon. Source: Wellcome Collection.

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    Reprinted from The Veterinary Journal, Voi. 83, No. 1] BACILLARY WHITE DIARRHCEA OF CHICKS (B.W.D.). By T. DALLING, J. H. MASON and W. S. GORDON, Wellcome Physiological Research Laboratories. The main problem we are now investigating with relation to B.W.D. is whether systematic testing by the agglutination method of all fowls in a breeding flock and the disposal of the positive reactors according to the methods developed during the past few years, particularly in U.S.A., will in England ultimately result in the entire prevention of the disease among chicks bred from the “ clean ” birds. All the indications are favourable hitherto, but such an investigation must extend over several years. A number of questions arise in carrying out this work which have been the subject of our investigation during the past three years. While this work was in progress the paper by Doyle (5) appeared covering some of the ground. It will be seen that we .confirm many of his findings, though not all. (a) The “ Carrier ” Fowl. It has been known for some years that the “ carrier ” hen is the chief source of spreading B.W.D. Rettger and Harvey (1) first showed that eggs laid by “ carrier ” hens may be infected with B. pullorum and that, if such eggs are fertilised and incubated, the developing chick may die before reaching maturity, or, if hatched out, may be infected with B.W.D. and spread the disease to healthy chicks in the same brood. We (2) have shown that litter, etc., infected by diseased chicks may retain infection for several weeks. At What Age can Infection with B. Pullorum per Os Take Place ?— We (3) showed that infection of young chicks up to six days old is easily brought about by feeding B. pullorum culture. We have experimented with older birds. Two laying hens, each one year old (Nos. 13 and 14) and six chicks aged six weeks were placed in a small pen and received 50 c.c. of B. pullorum 24 hours old broth culture mixed with their food dailv for one week. The chicks were bred from stock known to be negative reactors to many agglutination tests and the hens had been repeatedly tested and were negative on • all occasions. Agglutination tests were now carried out periodically for a period of seven months. One chick died nine days after the cessation of the feeding and a second on the 14th day. Six months later the remaining fowls were killed and post-mortem examinations were carried out. Table I is a summary of the experiment and shows that fowls up to one year old may be infected by feeding very large amounts of B. pullorum, and chicks six weeks old may die from such