The Response of Chickens Vaccinated Against Newcastle Disease Virus to Three Methods of Challenge

Abstract

THE introduction of Newcastle disease into this country several years ago, and the rapid spread into almost all states stimulated experiments to test various vaccines as immunizing agents against the disease. There has been no uniform procedure for carrying out the experiments, particularly with reference to the challenge of vaccinated birds. The following experiment was planned to determine the response of vaccinated chickens to a uniform dose of challenge material administered by the 3 different routes which are used most frequentlyMATERIALS AND METHODSThe vaccine used was the hamster-egg vaccine prepared from the 73rd intracerebral hamster passage as described by Reagan et al. (1950). Seven-week-old Rhode Island Red chickens from a Newcastle disease free source were used in the experiment. No neutralizing antibodies against Newcastle disease virus were found in the sera of the birds when examined by the hemagglutination-inhibition test. All birds were banded for identification.The chickens .