Abstract
WHILE there is ample evidence of the value of live Newcastle disease vaccines in reducing losses from the disease and, in general, modifying the problem of its control, vaccination breaks have been reported relatively frequently in the field. Scientific analysis of such breaks is one of the most difficult tasks in avian virology. It is doubtful that all contributing circumstances can ever be uncovered. The readiest explanation has been an assumed antigenic difference between the field and the vaccine strains.This report is concerned with epizootic outbreaks of Newcastle disease (ND) in Puerto Rico and the antigenic relationship of a representative causative virus to the B-l ND vaccine strain.FIELD OBSERVATIONSWidespread losses in Puerto Rican chickens of all ages, vaccinated against Newcastle disease with vaccines of different brands and by different schedules, led local representatives of an American feed company to request a field investigation. This was undertaken in …
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
