title: Isolation and biological properties of virulent subpopulations from lentogenic Newcastle disease virus strains.
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D005144:F Factor; D006388:Hemagglutinins; D007185:Incubators; D009521:Newcastle Disease / Q000382:microbiology*; D009522:Newcastle disease virus / Q000302:isolation & purification* / Q000472:pathogenicity / Q000648:ultrastructure; D013696:Temperature; D010948:Viral Plaque Assay; D014774:Virulence
chemical_list: D006388:Hemagglutinins