Molecular identification of local field isolated fowl pox virus strain from Giza governorate of Egypt

Abstract

Aim: Molecular identification of field isolated pox virus from infected chickens in Egyptian farms in 2012 by polymerase chain reaction (PCR). Materials and Methods: Isolation and identification of fowl pox virus (FPV isolate ch-08TK) from 30 day-old chickens manifesting pox lesions. The isolate was propagated successfully on chorioallantioc membrane of specific pathogen free (SPF) embryonated chicken eggs and clear pock lesions were observed. These lesions were homogenated and used to infected 4.5 SPF chickens and pigeons (via wing web route for chickens and via feather follicle route into the thigh of pigeons) using 10 EID /mL; uninoculated birds of each species were used as negative controls for determining the effect of isolated FPV strain. 50 Result: The isolated strain gave pathogenic takes 100% in chickens and 75% in pigeons. Virus identification by PCR was done using dream Tag master mix kit using the primers that targeted thymidinekinase (TK) gene. These primers were designed using Lasergene DNASTAR software Version 10. We used these primers to amplify a 305 bp fragment of the TK gene of FPV. Phylogenetic analysis of sequenced TK amplicone which reflects a new emerging isolate of the field isolated FPV gave very limited similarity (not exceeding 60%) with the published sequences. Thus FPV isolate ch-08 TK gene (with Accession No. KF314718 in Gen Bank) is different than canary, Egypt, 2012, P4b and Elsharqyia-FWPV2 FPV140 (FPV140); TKPV FPV140 (FPV140) and PGPV FPV (FPV140) which have been isolated from cases of avipox virus in 2011 from skin crust of different domesticated birds reared under the Egyptian backyard management system. Our sequencing and phylogenetic analysis of newly isolated virus using DNASTAR software Version 10 revealed that this virus differ from canary, Egypt, 2012, P4b and Elsharqyia-(FWPV2 FPV140 (FPV140); TKPV FPV140 (FPV140) and PGPV FPV (FPV140)) according to published data in Gen Bank. Conclusion: FPV (isolated ch-08 TK gene with Accession number KF314718 in Gen Bank) was isolated from 30 day old laying chickens suffering from pox lesions. We believe that this study is the first molecular identification of FPV strain from laying chickens in Egypt.