BIRD rOX VACCINES AM) HACTKHIXS 



Results. 



213 



[lif use of the vaccine as a curative measure resulted in a slifzlit iiiii)r<ive- 

 lUfut in the general condition of the treated liirds, luif did not cause any 

 diminution in number or extent of the lesions. 



OxE Attack of Bir» Pox Confeus ax Ijimuxity. 



All hirds recovering from the infection during tiie exjieriments were held 

 over for future use. Approxinialcly 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 

 imnumity 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 by the abo%e experimental data. Evidence indicates that it 

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

 tion among the birds which acquire this protection. 



The Efficiexcv of Bacterixs. 



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 Siibtilis 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 comjjlications 

 of the disease. 



Commercial avian mixed infection bacterins were not used. Their 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 witli iiotii pox and avian diphtheria, 

 the latter predominating, was treated with an autogenous bacterin. Several 

 of the worst cases of both fomis of the disea.se were examined bacteriologic- 

 ally and the following organisms isolated: Stnphi/lococci aureus and nU>vs, 

 Gaffkija (Slaphj/lococcus) tetr(uje}in, 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 2,000,0(30,000 

 organisms. 



