BIRD POX VACCINES AND BACTERINS 



Resultn. 



213 



The use of the vaccine as a curative mea.-.ure resulted in a slight improve- 

 ment in the general condition of the treated birds, hut did not cause any 

 diminution in number or extent of the lesions. 



One Attack of Buiu Pox Confers an Ihijiunity. 



All birds recovering from the infection during the experiments were held 

 over for future use. Approximately fifty days following complete recovery 

 from both types of the disease, a group of such birds was inoculated wtih 

 viruses B and C. Lesions of the disease failed to develop, indicating that one 

 attack of the disease, whether of avian pox or diphtheritic type, confers an 

 imnnmity of at least fifty days' duration. Four healthy birds which served 

 as controls developed pox in eight days with virus B, and in nine days with 

 virus C. 



This actively acquired immunity is undoubtedly of greater duration than 

 that demonstrated liy the above experimental data. Evidence indicates that it 

 lasts from two months to two years, depending upon the virulence of the infec- 

 tion among the birds which acquire this protection. 



The Efficiency oi' Bacteuins. 



Several infected flocks were available during the fall and winter of the past 

 year for treatment with bacterins. Autogenous bacterins were resorted to for 

 the control of the outbreaks. Eleven different organisms, aside from 

 the common SnhtUis group, etc. contaminators, were isolated from diseased 

 birds obtained from five outbreaks of bird pox and avian diphtheria. These 

 organisms were not constantly present in all cases of the disease, and as has 

 been previously stated, they are secondary invaders only. It appears, there- 

 fore, that an autogenous bacterin is indicated in preference to a stock bacterin. 

 Also, such a preparation is limited to the control of secondary complications, 

 of the disease. 



Commercial a\ian mixed infection bacterins were not used. Tlieir bacterial 

 content does not correspond to the specific bacteria isolated from lesions of 

 birds affected with the disease as it exists in Massachusetts. McNutt (18) in 

 referring to experimental data on the use of such a biologic concludes, "In 

 every case the death loss among the treated equaled or exceeded the loss among 

 the untreated. Usually the loss was greater among the treated." 



Flock 1. 



A pen, consisting of 112 birds affected with iioth pox and avian diphtheria, 

 tlie latter predominating, w.is treated with an autogenous bacterin. Several 

 of the worst cases of both forms of the disease were examined bacteriologic- 

 ally and the following organisms isolated: Staphi/lorocci anreus and nlbnn, 

 Gaffkya {Slaphi/lococcus) tetrcujevn, and an unknown, gram negative, short, 

 rod-shaped organism of the colon group. The bacterin, composed of these 

 organisms, was standardized so that one dose of 1 cc. contained 2,000,()00,00() 

 organisms. 



