University of Illinois Urbana-Champaign

First detection of otarine herpesvirus-1 in South America: Characterizing the epidemiology in a Peruvian pinniped population

Tang, Karisa Nichole

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TANG-THESIS-2019.pdf

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https://hdl.handle.net/2142/105177

Description

Title
First detection of otarine herpesvirus-1 in South America: Characterizing the epidemiology in a Peruvian pinniped population
Author(s)
Tang, Karisa Nichole
Issue Date
2019-04-23
Director of Research (if dissertation) or Advisor (if thesis)
Allender, Matthew C.
Committee Member(s)
  • Langan, Jennifer N
  • Colegrove, Kathleen M
Department of Study
Vet Clinical Medicine
Discipline
VMS-Veterinary Clinical Medcne
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2019-08-23T20:44:42Z
Keyword(s)
  • otarine herpesvirus
  • OtHV-1
  • pinniped
  • South American sea lion
  • Peruvian fur seal
  • otariid
  • herpes
Abstract
Otarine herpesvirus-1 (OtHV-1) is associated with high rates of urogenital carcinoma in free-ranging California sea lions (Zalophus californianus), but rarely considered a conservation concern in the southern hemisphere. The objective of this study was to survey free-ranging South American sea lions (Otaria byronia) and Peruvian fur seals (Arctocephalus australis unnamed subspecies) in Punta San Juan, Peru for OtHV-1 and to determine prevalence by demographic factors. Twenty-one percent (14/67) of urogenital swabs collected over three years (2011, 2014, 2015) from live pinnipeds tested positive with a pan-herpesvirus conventional PCR. Sequencing revealed 99% homology to OtHV-1 at the DNA polymerase gene. Urogenital, conjunctival, and oropharyngeal swabs collected from 136 live pinnipeds at Punta San Juan between 2011-2018 were then assayed using quantitative PCR for a segment of the OtHV-1 DNA polymerase gene. In total, 38.6% (51/132) of urogenital swabs, 5.6% (4/71) of conjunctival swabs, and 1.1% (1/90) of oropharyngeal swabs were positive for OtHV-1. Agreement in OtHV-1 detection between sampling sites was minimal to non-existent (Cohen’s Kappa=0.027-0.386). The most parsimonious multivariable logistic regression model predicting OtHV-1 detection (P < 0.0001) included species and age class, with South American sea lions (32/81, 39.5%) having a higher prevalence of OtHV-1 in urogenital swabs than Peruvian fur seals (19/51, 37.2%), and adults (46/95, 48.4%) having a higher prevalence than pups (5/37, 13.5%). In addition, female South American sea lions had higher copy numbers (median=8,819 copies/ng DNA) than males (median: 27 copies/ng DNA, P=0.012), and adult South American sea lions (median=219 copies/ng DNA) had higher copy numbers than pups (median: 3 copies/ng DNA, P=0.008). The much higher prevalence in adults compared with pups, as well as the higher sensitivity in urogenital swabs, suggests a sexual transmission, which is similar to California sea lions. These data provide insight into dynamics of the potentially oncogenic OtHV-1 in a novel ecosystem, emphasizing the importance of continued disease surveillance in vulnerable Peruvian marine mammal populations.
Graduation Semester
2019-05
Type of Resource
text
Permalink
http://hdl.handle.net/2142/105177
Copyright and License Information
Copyright 2019 Karisa Tang

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