title: First molecular detection and characterization of herpesvirus and poxvirus in a Pacific walrus (Odobenus rosmarus divergens).
abstract: BACKGROUND
  Herpesvirus and poxvirus can infect a wide range of species: herpesvirus genetic material has been detected and amplified in five species of the superfamily Pinnipedia; poxvirus genetic material, in eight species of Pinnipedia. To date, however, genetic material of these viruses has not been detected in walrus (Odobenus rosmarus), another marine mammal of the Pinnipedia clade, even though anti-herpesvirus antibodies have been detected in these animals.
  
  
  METHODS
  In February 2013, a 9-year-old healthy captive female Pacific walrus died unexpectedly at L'Oceanografic (Valencia, Spain). Herpesvirus was detected in pharyngeal tonsil tissue by PCR. Phylogenetic analysis revealed that the virus belongs to the subfamily Gammaherpesvirinae. Poxvirus was also detected by PCR in skin, pre-scapular and tracheobronchial lymph nodes and tonsils. Gross lesions were not detected in any tissue, but histopathological analyses of pharyngeal tonsils and lymph nodes revealed remarkable lymphoid depletion and lymphocytolysis. Similar histopathological lesions have been previously described in bovine calves infected with an alphaherpesvirus, and in northern elephant seals infected with a gammaherpesvirus that is closely related to the herpesvirus found in this case. Intracytoplasmic eosinophilic inclusion bodies, consistent with poxviral infection, were also observed in the epithelium of the tonsilar mucosa.
  
  
  CONCLUSIONS
  To our knowledge, this is the first molecular identification of herpesvirus and poxvirus in a walrus. Neither virus was likely to have contributed directly to the death of our animal.
authors.forename: Mar
authors.initials: M
authors.lastname: Melero
authors.forename: Daniel
authors.initials: D
authors.lastname: García-Párraga
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Corpa
authors.forename: Joaquín
authors.initials: J
authors.lastname: Ortega
authors.forename: Consuelo
authors.initials: C
authors.lastname: Rubio-Guerri
authors.forename: José Luis
authors.initials: JL
authors.lastname: Crespo
authors.forename: Belén
authors.initials: B
authors.lastname: Rivera-Arroyo
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Sánchez-Vizcaíno
mesh_terms: D000818:Animals; D000836:Animals, Zoo; D017809:Fatal Outcome; D005260:Female; D018142:Gammaherpesvirinae / Q000302:isolation & purification*; D006566:Herpesviridae Infections / Q000662:veterinary* / Q000821:virology; D010802:Phylogeny; D011212:Poxviridae / Q000145:classification / Q000302:isolation & purification*; D011213:Poxviridae Infections / Q000662:veterinary* / Q000821:virology; D014856:Walruses