Genetic and Antigenic Characterization of a Poxvirus Isolate from Ostriches

Abstract

Avian poxvirus was isolated from nodules on the heads and conjunctiva of two 3-to-4-wk-old ostrich chicks. The ostriches from which poxvirus was isolated had been placed on premises where turkeys that had shown evidence of poxvirus infection had been raised earlier. Microscopically, the nodules from the ostriches were composed of proliferating and hypertrophic epithelial cells that formed large fronds. Most of the hypertrophic epithelial cells contained large eosinophilic intracytoplasmic inclusion bodies characteristic of poxvirus. Characterization of the avian poxvirus isolated from the cutaneous lesions in ostriches was based on western blotting of virus antigen, restriction fragment length polymorphism of genomic DNA, pathogenesis, and cross-protection studies in chickens. Antigenic and genetic studies did not reveal any significant difference between the poxvirus isolated from ostriches (PVO) and fowl poxvirus (FPV). Further, susceptible chickens immunized with the PVO were protected when challenged with a virulent strain of FPV. Thus, the poxvirus isolated from ostriches had similar antigenic, genetic, and biological properties to FPV.

Phylogenetic analysis of three genes of Penguinpox virus corresponding to Vaccinia virus G8R (VLTF-1), A3L (P4b) and H3L reveals that it is most closely related to Turkeypox virus, Ostrichpox virus and Pigeonpox virus

“…Previous work has shown that OSPV, TKPV and FWPV are genetically, antigenically and biologically related. Ostrich chicks housed in an enclosure that had previously housed pox infected turkeys became infected with a poxvirus and immunisation of susceptible chickens with this poxvirus protected them from FWPV challenge [ 22 ]. OSPV isolated from ostriches in Israel was found to produce productive infection in turkeys and furthermore, ostrich chicks in both Israel and South Africa could be protected by immunisation with FWPV vaccine [ 23 , 24 ].…”

Reticuloendotheliosis Virus Sequences within the Genomes of Field Strains of Fowlpox Virus Display Variability

“…In fact, in only one instance occurring in 1956 could the perpetrator be considered to be a vaccine strain on the basis that its DNA had the small REV LTR fusion (13). That such FPV isolates can still be virulent was also shown by the ability of a virus exhibiting a similar REV genotype to produce lesions on the heads and conjunctiva of immunologically naïve ostriches (20). Quite possibly, FPV strains with such REV deletions in their DNAs or even unadulterated viruses still circulate in the environment, but continual immunization against fowlpox prevents their successful infection of poultry and subsequent detection.…”

Identification and Characterization of Fowlpox Virus Strains Using Monoclonal Antibodies

“…6 An incidence of at least 80% has been reported in aged gray horses, with a predilection for the perineal and tail regions. 5,6 It has been estimated that up to 66% of melanocytic tumors in horses eventually progress to malignancy; however, some show malignant behavior from the outset. The current report describes a poorly pigmented malignant melanoma in the dermis of a horse, in which tumor cells were arranged within unusually abundant stromal tissue.…”

“…In this regard, viruses genetically and antigenically similar to FPV vaccines have been found in turkeys and also in ostriches. 6 Moreover, the pigeonpox virusbased vaccines may also represent FPV ''cross-overs,'' in this case into pigeons. For instance, there is 100% homology between comparative pigeonpox and fowlpox virus entries in GenBank, and both MAbs used in this study react with similar-sized proteins in both viruses.…”

“…Melanomas represent 6-15% of reported cutaneous tumors in horses. 6 An incidence of at least 80% has been reported in aged gray horses, with a predilection for the perineal and tail regions. 5,6 It has been estimated that up to 66% of melanocytic tumors in horses eventually progress to malignancy; however, some show malignant behavior from the outset.…”