Poxvirus infection in a Steller's sea eagle (Haliaeetus pelagicus)

Abstract

A severely emaciated adult Steller's sea eagle (Haliaeetus pelagicus) was found dead with electrocution-induced severe wing laceration, and with multiple cutaneous pock nodules at the periocular regions of both sides nearby the medial canthi and rhamphotheca. Histopathological examination of the nodules revealed hyperplasia of the epidermis with vacuolar degeneration and intracytoplasmic inclusion bodies (Bollinger bodies). The proventriculus was severely affected by nematodes and was ulcerated. Nucleotide sequencing of a PCR-amplified product of Avipoxvirus 4b core gene revealed 100% identity to the sequence of Avipoxvirus derived from other eagle species. This report describes the first detection of Avipoxvirus clade A from a Steller's sea eagle.

Keywords: 4b gene; Avipoxvirus; Japan; Steller’s sea eagle.

Fig. 1.

Figure 1A and 1B showed multiple crusts on the skin of both sides of the beak, mostly on the medial canthi of the right (A) and left eyes (B). (C) Ulcerative parasitic nodule of the proventriculus mucosa with large numbers of nematodes. (D) Cutaneous lesion in a Steller’s sea eagle. Necrosis and proliferation were observed in the stratum spinosum. H&E, bar=500 µm. (E) Large eosinophilic inclusion bodies (Bollinger inclusions) were seen in the cytoplasm of epidermal cells. H&E, bar=50 µm.

Fig. 2.

Gel electrophoresis of the amplification product of the Avipoxvirus 4b core gene from crusted cutaneous lesions. A positive band of approximately 576 bp is detected.

Fig. 3.

Phylogenetic tree of the Avipoxvirus 4b core gene sequence. Sequences from various avian hosts are represented on the cladogram by accession numbers in GenBank and their geographic locations. The black square indicates the sequence obtained from the present case of a Steller’s sea eagle (accession number MG934698). Bootstrap values were calculated with 1,000 replicates and were located on the nodes or the bifurcation points of the tree branches. The scale bar represents the genetic distances among different taxa included in the neighbor-joining tree. The Avipoxvirus 4b gene sequence under accession number LC055564 isolated from a large-billed crow (Corvus macrorhynchos) was utilized as out-group.