Pigeon pox disease is caused by pigeon pox virus (PPV) that classified within Family Poxviridae, subfamily Chordopoxvirinae, genus Avipoxvirus (APV) which has the largest and the most divergent genome among the chordopoxvirus genera with many species like PPV, Fowl pox virus (FPV) and Turkey pox virus (TPV) (Andraw, 2012). Pigeon pox is a slowly spreading disease characterized by the development of discrete proliferative nodular skin lesions (cutaneous form) characterized by nodular lesions on feather free areas of skin such as legs, peak and eyelids with low mortality and/or fibrino-necrotic lesions on the mucous membrane of the upper respiratory tract (diphtheritic form) with high mortality. In both forms, gross lesions consist of small vesicles that progress further to nodules and finally scab formation Khan et al. (2009) and Hemanth et al. (2014). The conventional laboratory diagnosis of FPV is carried out by electron microscope, virus isolation on chorioallantoic membrane (CAM) of embryonated chicken eggs (ECE) and serologic methods as Virus Neutralization test (VNT) on ECE (Islam et al., 2008). PPV has a double stranded DNA genome which contains a central coding region surrounded by two identical inverted terminal repeat regions. The genome size is 288 kbp approximately and encodes 260 open reading frames Weli et al. (2011). The 4b core protein gene (P4b) of APV encoding a protein with a molecular weight of 75.2 kDa, is usually chosen for comparative genetic analysis. On the other hand, amplification of the AP-p4b by PCR has often been used as a molecular tool for the detection of avian poxviruses (Manarolla et al., 2010). Based on the phylogenetic analysis of (P4b), APV are divided into three clades; clade A (FPV), clade B (Canary Pox virus), and clade C (Psittacine pox virus) (Offerman et al., 2014).

Evaluation of the humoral immune response against Lumpy Skin Disease (LSD) in vaccinated and infected cattle is a very important issue for controlling it in Egypt. This study was conducted to evaluate and compare newly commercial ELISA kit and traditional virus neutralization test (VNT) using sheep pox virus (SPV) and Lumpy Skin Disease Virus (LSDV) for monitoring the humeral response against LSDV. Sensitivity and specificity of VNT were higher in case of using LSDV (96% and 100%, respectively) than in case of using SPV (89.3% and 98.6%, respectively) while they were 98.6% and 97.3%, respectively in case using of commercial ELISA Kit, which detected the highest number of positive samples (n =76) and (70 %) followed by VNT using LSDV (n =72) and (67.5 %) and finally VNT using SPV (n =68) and (67.5 %) for tested 150 control and 200 field samples respectively. The agreement between VNT using SPV and ELISA was achieved in ( 67) and ( 123) positive, ( 73) and ( 58) negative control and field samples, respectively, with overall proportion agreement (Po) as 0.93 and 0.90 with Kappa index of 0.86, and 0.78 for control and field samples respectively, while in case of using LSDV the agreement between VNT and ELISA was achieved in ( 72) and (134) positive, ( 74) and ( 59) negative control and field samples with overall proportion agreement of 0.97 and 0.96 with a Kappa index of 0.94 and 0.90 for control and field-tested samples respectively. Using hyperimmune sera prepared against LSD, the highest dilution gave positive results in the commercial ELISA kit and VNT using LSDV was 1/128 while it was 1/64 using SPV. This study illustrated that the VNT using LSDV is the most specific serological test for detecting LSD antibodies rather than ELISA commercial kit and VNT using SPV. Still, the test is not as sensitive enough as the commercial ELISA kit which was the most sensitive test for detection of LSD antibodies in vaccinated and infected cattle.

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.

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.