A Comparison of Parapoxviruses in North American Pinnipeds.

Helena Costa,Mendy Garron,Todd Schmitt,Jörn Klein,Hendrik H Nollens,Tracey Goldstein,Padraig J Duignan,Keith Matassa,Morten Tryland,Eva M Breines

doi:10.3389/fvets.2021.653094

Abstract

Parapoxviruses cause nodular lesions on the skin and mucosal membranes of pinnipeds and infections by these viruses have been documented worldwide. Seal parapoxvirus is currently classified as a tentative species of the Parapoxvirus genus. Tissue or swab samples were analyzed from 11 pinnipeds of different host species undergoing rehabilitation on the east and west coasts of the United States of America (USA) that were positive for parapoxvirus. The aim of the study was to compare parapoxvirus sequences of fragments of the B2L, DNA polymerase, GIF and viral interleukin-10 ortholog (vIL-10) genes and to examine the evolutionary relationship between viruses detected in different pinniped species and at different locations with other members of the Parapoxvirus genus, such as Orf virus (ORFV), Bovine papular stomatitis virus (BPSV) and Pseudocowpox virus (PCPV). The sequence analysis showed that the parapoxvirus sequences from the pinnipeds differed significantly from those found in terrestrial hosts and that they formed a separate cluster within the genus. Our results suggest that transmission of the same parapoxvirus strain is possible between different species, including between members of different families (phocids and otariids). Animals belonging to the same species but living in distant geographic locations presented genetically distant parapoxviruses. The findings of this study demonstrate that sealpox lesions in pinnipeds of different species are caused by viruses that belong to the Parapoxvirus genus but have significant genetic differences compared to the established virus species in terrestrial hosts, thus strongly supporting the classification of pinniped parapoxvirus as a new species of the genus.

Highlights

Parapoxviruses cause nodular lesions on the skin and mucosal membranes of pinnipeds and pox infections have been documented worldwide in animals admitted to rehabilitation facilities [1,2,3,4,5,6,7,8] and in free-ranging animals [8,9,10,11,12]
Pinniped parapoxviruses are currently classified as the tentative species “seal parapoxvirus” in the Parapoxvirus genus, of which the recognized members include Orf virus (ORFV), Bovine papular stomatitis virus (BPSV), Pseudocowpox virus (PCPV) and Parapoxviruses in North American Pinnipeds parapoxvirus of red deer in New Zealand (PVNZ) [13]
The other exception to the clustering according to pinniped species was the sequence from the Northern elephant seal (UiT10) that clustered with three sequences from California sea lion parapoxvirus (UiT12, UiT9, and DQ163058.1) in the B2L tree

Summary

Introduction

Parapoxviruses cause nodular lesions on the skin and mucosal membranes of pinnipeds and pox infections have been documented worldwide in animals admitted to rehabilitation facilities [1,2,3,4,5,6,7,8] and in free-ranging animals [8,9,10,11,12]. Pinniped parapoxviruses are currently classified as the tentative species “seal parapoxvirus” in the Parapoxvirus genus, of which the recognized members include Orf virus (ORFV), Bovine papular stomatitis virus (BPSV), Pseudocowpox virus (PCPV) and Parapoxviruses in North American Pinnipeds parapoxvirus of red deer in New Zealand (PVNZ) [13]. Pinnipeds infected with parapoxvirus typically develop one or more firm skin nodules, 1 to 3 cm in diameter, usually affecting the head, neck, flippers and thorax [16]. These lesions frequently heal spontaneously, resolving, in most cases, in 4–6 weeks [17]. Parapoxvirus infections are diagnosed through clinical evaluation of skin and mucosal lesions, virus isolation, electron microscopy [20], serological tests [21] and molecular detection [16, 22]

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