title: [In vivo persistence of plaque mutants of viscerotropic Newcastle disease virus].
abstract: 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.
mesh_terms: D000818:Animals; D002645:Chickens; D005455:Fluorescent Antibody Technique; D009154:Mutation; D009521:Newcastle Disease / Q000382:microbiology*; D009522:Newcastle disease virus / Q000235:genetics* / Q000472:pathogenicity; D009924:Organ Culture Techniques; D014132:Trachea; D010948:Viral Plaque Assay; D014774:Virulence
vernacular_title: Perzistirane na plakovi mutanti in vivo na velogenen vistserotropen virus na psevdochumata.