Abstract
Poxviruses in pinnipeds have been recognized for decades1 and are known to be zoonotic.2,3 Nodular skin lesions are often seen in infected pinnipeds and humans.2,3 Most reported poxviral infections of seals and sea lions are characteristic of the genus Parapoxvirus. However, one grey seal appeared to have a mixed infection of parapoxvirus and orthopoxvirus particles on negative-staining electron microscopy4 and a Steller sea lion poxvirus has been proposed to represent a new, separate genus within Chordopoxvirinae based on neighbor-joining phylogeny of DNA polymerase and topoisomerase I gene fragments.5
Clinical samples from harbor seals (n = 4) and grey seals (n = 2) were used in tissue culture isolation and propagation using primary ringed seal (Phoca hispida) and beluga (Delphinapterus leucas) kidney cell lines, followed by PCR amplification, sequencing, and phylogenetic analyses. Three of the harbor seal samples yielded poxviral isolates, which were identical to each other. Both grey seal samples yielded poxviral isolates which were also identical to each other yet distinct from the harbor seal. The harbor seal isolate was similar to, differing by only one amino acid, Harbor Seal Poxvirus-1 (Genbank accession #: AF414182) and the grey seal isolate showed identity to Grey Seal Poxvirus-1 (DQ273134), again differing by only 1 amino acid. Bayesian and Maximum Likelihood analyses were used to evaluate the partial, putative virion envelope antigen (p42K) region of Chordopoxvirinae with emphasis on pinniped parapoxviruses (n = 9). The pinniped parapoxviruses clustered together in a subclade which is in agreement with the neighbor-joining analysis.6
Acknowledgements
Funding is provided through the University of Florida Marine Animal Disease Laboratory, the Florida Fish and Wildlife Conservation Commission, the UF Whitney Marine Laboratory for Marine Bioscience and the UF Aquatic Animal Health program at the College of Veterinary Medicine. UF IACUC permit #: 200801853.
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