Abstract
Thirteen novel avipoxviruses were isolated from birds from different regions of South Africa. These viruses could be divided into six groups, according to gross pathology and pock appearance on chick chorioallantoic membranes (CAMs). Histopathology revealed distinct differences in epidermal and mesodermal cell proliferation, as well as immune cell infiltration, caused by the different avipoxviruses, even within groups of viruses causing similar CAM gross pathology. In order to determine the genetic relationships among the viruses, several conserved poxvirus genetic regions, corresponding to vaccinia virus (VACV) A3L (fpv167 locus, VACV P4b), G8R (fpv126 locus, VLTF-1), H3L (fpv140 locus, VACV H3L) and A11R–A12L (fpv175–176 locus) were analysed phylogenetically. The South African avipoxvirus isolates in this study all grouped in clade A, in either subclade A2 or A3 of the genus Avipoxvirus and differ from the commercial fowlpox vaccines (subclade A1) in use in the South African poultry industry. Analysis of different loci resulted in different branching patterns. There was no correlation between gross morphology, histopathology, pock morphology and phylogenetic grouping. There was also no correlation between geographical distribution and virus phenotype or genotype.
Highlights
Avipoxviruses (APVs) are large, complex DNA viruses that belong to the subfamily Chordopoxvirinae of the family Poxviridae (ICTV, 2012)
The 11 APV isolates could be divided into six groups, separate from canarypox virus (CNPV), based on pock and chorioallantoic membranes (CAMs) morphology (Table 1)
CNPV, penguinpox virus (PEPV; from a penguin) and Pi2 caused no obvious membrane thickening, but the pock lesions produced by these viruses each differed in colour, size and density (Fig. 1)
Summary
Avipoxviruses (APVs) are large, complex DNA viruses that belong to the subfamily Chordopoxvirinae of the family Poxviridae (ICTV, 2012) They have been shown to naturally infect more than 278 of the approximately 9000 species of wild and domestic birds (Van Riper & Forrester, 2007). As APVs are often not host specific and differ with respect to their virulence, the current means of taxonomy and classification has been criticized (Jarmin et al, 2006; Manarolla et al, 2010). Further characterization of this genus is necessary. Case reports have described the growth characteristics of individual APV isolates (Boosinger et al, 1982; Haligur, et al 2009; Kulich et al, 2008; Rampin et al, 2007)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
