BIRD POX VACCINES A'SD BACTKRINS 



209 



Interpretation 



1. The filtered virus produced pox, roup, and avian di])litiieria, indicating 

 thai one and the same virus is capable of causing all forms of the disease. 



2. Bird No. 2 had a simple catarrh when inoculated. This evidently low- 

 ered the resistance of mucous membranee surfaces and avian diphtheria 

 followed. ■ * 



3. The incubation period of the filtered virus was from twelve to eifthteen 

 days, while in the case of the unfiltered virus it ranged from seven to nine 

 days. The liltered virus also i)roduced a less pronounced form of tiie infec- 

 tion than did the unhltered virus. These latter two points confirm the work 

 of Schinid (8) in 1909. 



A bacteriological examination of the unfiltered powdered virus revealed 

 several secondary invaders, such as P.seudomonas aeruginoxa and various 

 Staphylococci. These organisms imdoubtedly assisted the unfiltered virus in 

 causing a shorter period" of incubation and a more pronounced form of the 

 di.'^ease. 



The Uniformity of the Viuulexce of Commercial Viruses. 



Before studying the efficiency of the powdered pox virus vaccines, it was 

 desirable to ascertain the strength of tlie viruses which make up these com- 

 mercial products. 



Four groups of birds were inoculated on October 5th with four different 

 strains of powdered pox virus. The course of the disease subsequent to the 

 inoculation is represented by the respective lines A, B, C, and D in the fol- 

 lowing graph. Virus A was obtained on October 1 from a natural infection 

 in Massachusetts and viruses B, C, and D were of commercial origin. 



Chart I. Variance in Strength of Powdered Pox Viruses. 



-|- Period of incubation. 

 -|-.|- Appearance of a few or several well formed pox nodules. 

 -|--|.-|- Appearance of many pox nodules of mature development. 

 -|--|--j--|- Maximum development of pox nodules. 

 Downward curves — Periods of recovery. 



^'irus A siiowed the greatest potency. The period of incubation was seven 

 days, the disease reaching its maxinuun development three days later, and 

 death following within twenty-three days with no appreciable evidence of 

 recovery. 



Virus B showed the greatest potency of the three commercial stock viruses. 

 The period of incubation was eight days, maximum development four days 

 later, and com])lete recovery in twenty-two days more. 



