Integration of the reticuloendotheliosis virus envelope gene into the poultry fowlpox virus genome is not universal.
Fowlpox virus (FWPV) is found worldwide in poultry and wild birds. FWPV is a natural example of recombination between viruses, as reticuloendotheliosis virus (REV) fragments have been found in all poultry FWPVs and these are implicated in virulence alteration. We aimed to determine the commonality of this phenomenon and analysed FWPVs collected from 128 poultry flocks and birds over the last 10 years. Various fragments of both viruses were amplified and sequenced at the FWPV integration site, located between FWPV open reading frames 201 and 203. Seven isolates were found to contain no REV insertions, including fragments of the REV env, gag and 5' REV-long terminal repeat (LTR). We demonstrate here for the first time, the existence of poultry FWPVs without REV inserts (two from chickens, one from turkey FWPV and four from wild birds). The REV inserts were heterogeneous in size. In addition to poultry and wild bird isolates, three FWPV vaccine virus strains were examined and found to contain only remnant REV-LTR and no REV envelope gene fragments.
Davidson
Irit
I
Division of Avian and Fish Diseases, Kimron Veterinary Institute, PO Box 12, Bet Dagan 50250, Israel.
Shkoda
Irena
I
Division of Avian and Fish Diseases, Kimron Veterinary Institute, PO Box 12, Bet Dagan 50250, Israel.
Perk
Shimon
S
Division of Avian and Fish Diseases, Kimron Veterinary Institute, PO Box 12, Bet Dagan 50250, Israel.
D000818:Animals; D000835:Animals, Wild; D001715:Bird Diseases / Q000821:virology; D002645:Chickens; D005586:Fowlpox / Q000821:virology; D005587:Fowlpox virus / Q000235:genetics*; D016679:Genome, Viral; D011201:Poultry Diseases / Q000821:virology; D017986:Reticuloendotheliosis Viruses, Avian / Q000235:genetics*; D055761:Reticuloendotheliosis, Avian / Q000662:veterinary / Q000821:virology; D020079:Terminal Repeat Sequences; D014422:Turkeys; D014759:Viral Envelope Proteins / Q000235:genetics*; D014765:Viral Vaccines; D016662:Virus Integration
D014759:Viral Envelope Proteins; D014765:Viral Vaccines