This study presents a local isolate of fowl pox virus (FPV) isolated and propagated from backyard naturally infected laying hens in El-Sharkia Governorate, Egypt, during the period of January to November 2017. Isolation and propagation were carried out from collected skin lesions on the chorioallantoic membrane (CAM) and chicken embryo fibroblast (CEF) with obtained 4 th passage virus titers 4.0 Log 10 EID 50 /ml at the in CAM and 3.5 Log 10 TCID 50 /ml in CEF respectively. They showed characteristic pock lesions of FPV and cytopathic effect (CPE) of FPV at the 3 rd passage on CAM and CEF, respectively. Virus neutralization test (VNT) results confirmed that the obtained isolate is FPV. Molecular characterization of (Sharkia2017/VSVRI) was performed with Polymerase chain reaction (PCR) to amplify 578 bp of P4b (fpv167) gene and 1150 bp of fpv140 gene. Sequence and phylogenetic analysis of both genes confirmed the relatedness of (Sharkia2017/VSVRI) isolate to sub-clade A1 of fowl pox viruses with 99.7-100% identity to fowl pox virus sequences published in GenBank.This study reports the antigenic and genomic characterization of the locally isolated FPV (Sharkia2017/VSVRI) using VNT and PCR confirmed by sequence analysis to help in the production of FPV tissue culture vaccine from the obtained local FPV after confirming its immune response as a candidate vaccine.

In this study, the duration of immunity as well as maternally derived antibodies (MDA) induced by the innovated tissue culture pigeon pox vaccine (TC-PPV) were evaluated for the first time. It was found that the postvaccinal reaction was more prominent in pigeons vaccinated with egg-adapted PPV (EG-PPV) (100%) than in pigeons vaccinated with TC-PPV (88%). The duration of induced immunity was higher using EG-PPV (1 year with a peak of neutralizing antibodies index 3.25 while it was 2.75 using TC-PPV) after 1 month of vaccination. MDA in squabs of vaccinated dams with TC-PPV maintained the protective level of antibodies up to 3weeks post-hatching (WPH) with 100% protection against a challenge. In contrast, in squabs of vaccinates with EG-PPV, it remained up to 4 WPH with 90 % protection. Such antibody levels hinder the immune response to vaccination with TC-PPV resulting in vaccination failure with 40% protection for squabs of TC-PPV vaccinated dams at 3 rd WPH and 60% protection for squabs of EG-PPV vaccinated dams at 4 th WPH reflecting the successive vaccination at the 4 th WPH and 5 th WPH, respectively for hatched squabs with 80% protection in both groups while in squabs of unvaccinated dams; the vaccination with TC-PPV appears to be protective from 2nd WPH with 100% protection. In addition, this study recommends revaccination of pigeons with TC-PPV after 10 months and vaccination of their squabs not before 4 WPH to avoid vaccination failure by MDA.