Detection and molecular characterization of avipoxviruses isolated from different avian species in Egypt

Abstract

Six clinical cases of avipoxvirus (APV) infection were investigated and molecular biologically studied. The samples were collected from different domesticated birds reared in the Egyptian backyard management system and were propagated on the chorioallantoic membrane of embryonated chicken eggs. The virus isolation was confirmed via PCR amplification of fpv167 (P4b) gene locus. All the studied isolates were characterized as Fowlpox-like viruses based on the amplicon length of fpv140 gene locus. The phylogenetic analysis of fpv167 (P4b) gene clustered Elsharqyia_FWPV1, Elsharqyia_FWPV2, Elsharqyia_FWPV3, Elsharqyia_FWPV4, and Elsharqyia_TKPV strains within subclade A1. Furthermore, Elsharqyia_PGPV strain was clustered within subclade A2 (Turkeypox virus) and showed 100 % nucleic acid identity with the wood pigeon Indian which was isolated in 2009. On the other hand, when the fpv140 gene was used for the phylogenetic analysis, Elsharqyia_PGPV was clustered within subclade A4 (Pigeonpox virus) with the other PGPVs. This study is considered the first molecular record for APVs circulating in the Egyptian birds. Further studies in a larger scale need to be developed to have a better understanding about the molecular characterization of the Egyptian APV strains.

Diversity of avipoxviruses in captive-bred Houbara bustard

“…Classically, APV are considered to be host species or order specific and taxonomy was based on this concept. This has been recently questioned by many authors [4][5][6]23] since some taxa like Columbidae and Accipitridae can be infected by a wide diversity of strains, however with different sensitivity depending on the virus involved. This apparent diversity could be explained by some infections occurring as accidental events, especially in zoological collections where many species are housed closely, and it is suggested that such an infection could not lead to sustainable epornitics [23].…”

“…Other genes have been used in order to validate or improve findings based on fpv167. The fpv140 locus (fpv139, fpv140 and fpv141 genes), has also been used [4] and the phylogenetic analyses based on fpv140, orthologous of vaccinia virus H3L gene encoding a virion envelope protein p35, have provided improved strain discrimination within some subclades [5][6][7]. Phylogenetic analyses have all shown the same distribution of APV into 3 clades: fowlpox virus-like (FWPV-like, clade A), canarypox virus-like (CNPV-like, clade B), and psittacinepox virus-like (clade C).…”

Time scale evolution of avipoxviruses

“…Classically, APV were considered to be host species-or orderspecific. Genus taxonomy had been based on this concept until recent studies showed that Otididae, Columbidae and Accipitridae can be infected by a large diversity of strains (Abdallah and Hassanin, 2013;Gyuranecz et al, 2013;Jarmin et al, 2006;Le Loc'h et al, 2014). The age of divergence between the three main APV clades has not been estimated.…”

The emergence of subclades A1 and A3 avipoxviruses in India

“…The DNA polymerase gene is used as a marker for the molecular characterization of APV isolates (Abdallah & Hassanin, ; Gyuranecz et al, ; Lecis et al, ; Mapaco et al, , ). For this reason, we performed a phylogenetic analysis with the DNA polymerase gene for the first time with Indian isolates.…”

“…Recently, molecular biological methods such as PCR have emerged as a gold standard technique for routine avipoxvirus diagnosis. The highly conserved loci of the viral genome, such as the gene encoding the P4b core protein (FPV167) and the viral DNA polymerase (FPV094), are targeted for PCRbased diagnosis and phylogenetic analysis (Abdallah & Hassanin, 2013;Gyuranecz et al, 2013;Lecis et al, 2017;Mapaco et al, 2017Mapaco et al, , 2018. A phylogenetic tree constructed based on these loci revealed that avipoxviruses cluster into three major clades, A, B and C, with clades A and B being subdivided further into A1, A2, A3, A4, B1 and B2 (Gyuranecz et al, 2013;Jarmin et al, 2006;Manarolla, Pisoni, Sironi, & Rampin, 2010).…”