Submitted to: American Association of Avian Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 7/18/2001
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Molecular characterization of Australian vaccine and field strains of fowlpox virus (FPV) have shown the presence of a near full length infectious reticuloendotheliosis virus (REV) genome integrated into a vaccine strain of FPV. Fowlpox vaccines contaminated with REV have also been identified in samples from the USA. However, it is not known if the apparent contamination is due to free REV or to REV arising from integrated provirus. The objective of this study is to determine if REV contaminated FPV strains arise from free or genome integrated REV. Polymerase chain reaction (PCR) amplification procedures were developed to screen for REV sequences in one vaccine and four field strains of FPV. Three of the field isolates and the vaccine strain showed positive amplifications using REV primers located at LTR, env, pol, and gag regions, indicating the presence of different sequences of REV provirus in FPV preparations. Using FPV primers, which flank the previously identified LTR REV region within FPV, amplification was obtained from three of five samples. In addition, using REV and FPV primers, located at the REV env and at the FPV PK gene, three of the five samples tested positive by PCR. The data, indicate that REV sequences are integrated in three FPV samples. Sequence analyses are being conducted to find the exact site and extent of REV integration.