Characterization of poxviruses from forest birds in Hawaii

Two strains of avian pox viruses were isolated from cutaneous lesions in Ha waiian crows (Corvus hawaiiensis) examined in 1994 and a third from a biops y obtained in 1992 from an infected bird of the Apapane species (Himatione sanguinea) by inoculation of the chorioallantoic membranes (CAM) of develop ing chicken embryos. The resulting proliferative CAM lesions contained eosi nophilic cytoplasmic inclusion bodies characteristic of pox virus infection . The pathogenicity of these three viruses in domestic chickens was mild as evidenced by the development of relatively minor lesions of short duration at the sites of inoculation. Their virulence in this host was similar to t hat of a fowlpox virus (FPV) vaccine strain and contrasted greatly with the ability of two field strains of FPV to produce extensive proliferative les ions. One of the Hawaiian crow pox virus isolates as well as the one origin ating from the Apapane species could be propagated in two secondary avian c ell lines, QT-35 and LMH. A comparison of the restriction fragment length p olymorphisms (RFLP) of the genomes of the two cell line-adapted viruses, ge nerated by EcoRI digestion, revealed a limited degree of similarity. Moreov er, neither profile was comparable to those of the two field isolates of FP V, which were almost indistinguishable from each other. Thus, based on the genetic distinctness of the two Hawaiian bird viruses, they appear to repre sent different strains of avipoxvirus.