title: High-virulence Marek's disease virus infection in chickens previously infected with low-virulence virus.
mesh_terms: D000367:Age Factors; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D000956:Antigens, Viral / Q000032:analysis; D002060:Bursa of Fabricius / Q000502:physiology; D002645:Chickens; D006564:Herpesviridae / Q000472:pathogenicity*; D007114:Immunization; D008221:Lymphoid Tissue / Q000276:immunology; D008380:Marek Disease / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control; D011201:Poultry Diseases / Q000382:microbiology; D014422:Turkeys; D014774:Virulence; D014779:Virus Replication
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral