In vivo persistence of plaque mutants of viscerotropic Newcastle disease virus
Gerganov, G.; Surtmadzhiev, K.
Veterinarno-Meditsinski Nauki 18(7): 26-33
1981
ISSN/ISBN: 0324-1068 PMID: 7046219 Document Number: 171024
Studied was the persistance of 3 plaque clones of a velogenic viscerotropic Newcastle disease virus in nonimmune birds. It was found that the first plaque clone (4 mm dia of plaques) possessed higher virulence than that of the parental virus and killed all inoculated birds for 2 to 5 days. Plaque clone II (2.5 mm dia of the plaques) caused up to 30 per cent mortality, and plaque clone III (1.5 mm dia of the plaques) did not bring about death but a transient disease only. Birds inoculated with II and III plaque clones, at identical serologic response, were investigated virologically on the 40th and 60th day post infection. By means of the tracheal organ cultures the Newcastle disease virus was isolated only from birds that were inoculated with plaque clone II. No virus was demonstrated via the same method in birds inoculated with plaque clone III. It is believed that the long-term persistance of the Newcastle disease virus reported on a previous occasion was due to a subpopulation identical with plaque clone II.