Lack of contact transmission of recombinant Marek's disease virus type 1 expressing the fusion protein of Newcastle disease virus

To clarify the level of excretion of a recombinant Marek's disease virus ty pe 1 (rMDV1) that confers good protection in chickens against both Marek's and Newcastle diseases, even in the presence of maternal antibodies, contac t transmission tests were conducted. Naive chickens kept in the same cage o r room with chickens inoculated with rMDV1 did not produce antibodies again st MDV1 or the fusion protein of Newcastle disease virus. Moreover, the rMD V1 was not isolated from the dander of chickens inoculated with rMDV1. Even under the stressful conditions of forced molting and a high temperature en vironment. rMDV1 was not isolated from the dander of inoculated birds. The viral DNA, however, was detected from the dander of chickens inoculated wit h rMDV1 as well as a commercial vaccine. These findings indicate that dande r from chickens inoculated with rMDV1 includes viral DNA, but does not cont ain infectious virus. (C) 2001 Elsevier Science Ltd. All rights reserved.