title: An outbreak of lymphomas in a layer chicken flock previously infected with fowlpox virus containing integrated reticuloendotheliosis virus.
abstract: Visceral lymphomas occurred in a 236-day-old layer flock previously diagnosed with reticuloendotheliosis virus (REV)-integrated fowlpox virus (FPV) infection at the age of 77 days. Common pathologic lesions were multiple neoplastic nodules of homogeneous lymphocytes in the livers and spleens of all submitted chickens. All neoplastic tissues were positive for the REV envelope (env) gene by PCR. In a retrospective molecular study of FPV-infected 77-day-old chickens from the same flock, we identified nearly full-length REV provirus integrated into the genome of FPV as well as the REV env gene in trachea samples, whereas only the REV LTR region was present in the FPV strain used to vaccinate this flock. The 622-bp REV env gene nucleotide sequence derived from the trachea and neoplastic tissues was identical. Commercial ELISA of serum samples revealed that all chickens aged between 17 and 263 days in this flock were positive for REV but not for avian leukosis virus. Taken together, the evidence suggests that the visceral lymphomas were caused by a REV-integrated FPV field strain. FPV infections of commercial chickens should be followed up by careful monitoring for manifestations of REV infection, including lymphomas and immune depression, considering the ease with which the REV provirus appears to be able to integrate into the FPV genome.
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: B S
authors.initials: BS
authors.lastname: Koo
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: H R
authors.initials: HR
authors.lastname: Lee
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: E O
authors.initials: EO
authors.lastname: Jeon
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Jang
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: M S
authors.initials: MS
authors.lastname: Han
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: K C
authors.initials: KC
authors.lastname: Min
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: S B
authors.initials: SB
authors.lastname: Lee
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: J J
authors.initials: JJ
authors.lastname: Kim
authors.affiliation: Avian Disease Laboratory, College of Veterinary Medicine, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: I P
authors.initials: IP
authors.lastname: Mo
mesh_terms: D000818:Animals; D001353:Avian Leukosis / Q000453:epidemiology / Q000821:virology; D001354:Avian Leukosis Virus / Q000302:isolation & purification; D002645:Chickens; D004196:Disease Outbreaks / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D005586:Fowlpox / Q000150:complications / Q000453:epidemiology / Q000821:virology; D005587:Fowlpox virus / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D015752:Genes, env; D015994:Incidence; D008223:Lymphoma / Q000453:epidemiology / Q000473:pathology / Q000662:veterinary* / Q000821:virology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000453:epidemiology* / Q000821:virology; D011533:Proviruses / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D056910:Republic of Korea / Q000453:epidemiology; D001356:Reticuloendotheliosis virus / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D055761:Reticuloendotheliosis, Avian / Q000453:epidemiology / Q000821:virology; D012189:Retrospective Studies; D017423:Sequence Analysis, RNA / Q000662:veterinary
chemical_list: D012367:RNA, Viral