title: Close relationship between TRT virus isolates.
mesh_terms: D000818:Animals; D011201:Poultry Diseases / Q000382:microbiology*; D012141:Respiratory Tract Infections / Q000382:microbiology / Q000662:veterinary*; D014422:Turkeys / Q000382:microbiology*; D014777:Virus Diseases / Q000382:microbiology / Q000662:veterinary; D014780:Viruses / Q000302:isolation & purification*