A compressor from an ordinary paint sprayer and a nasai afomizer comprise the equipment for 

 vaccinating this flock of chicks against Newcastle disease. Pholo by John H. Vondell. 



adequate protection. Tests have 

 been carried on to see whether in- 

 creased protection could be ac- 

 complished by revaccinating the 

 birds at approximately four weeks 

 of age by spraying the flock with the 

 Bi strain of virus. This method has 

 proved beneficial in "boosting" im- 

 munity after day-old vaccination; 

 such revaccination in broiler flocks 

 may be justified in heavily infected 

 areas during the winter season. To 

 be effective, however, the vaccine 

 sprayed must have a high concen- 

 tration of live-virus particles. Since 

 the present conunercial intranasal 

 vaccines are not satisfactory for 

 this method of administration, work 

 is imder way to develop a product 

 that can be applied by the spray 

 method. 



Increased Immunity Sought 



The spray method of administra- 

 tion, considered during the early 



studies on the intranasal type of 

 vaccine, was rejected because of 

 the severe reaction it induced in 

 susceptible baby chicks. Mere re- 

 cent trials at the Virginia Experi- 

 ment Station have revealed that the 

 vaccine can be sprayed for vaccinat- 

 ing baby chicks under controlled 

 conditions. Studies directed here in 

 Amherst towards the application of 

 the vaccine in birds three to four 

 weeks of age or older have revealed 

 that spraying will give good im- 

 munity response without serious 

 reaction. This method of applica- 

 tion is being studied in field flocks 

 as a method of initial vaccination 

 as well as a method of revaccina- 

 tion to increase the immunity of 

 previously vaccinated flocks. The 

 results to date have been very en- 

 couraging and open new possibili- 

 ties for an easy method of flock 

 vaccination against Newcastle dis- 

 ease. 



