Transmission of ranavirus between ectothermic vertebrate hosts

PLoS One. 2014 Mar 25;9(3):e92476. doi: 10.1371/journal.pone.0092476. eCollection 2014.

Abstract

Transmission is an essential process that contributes to the survival of pathogens. Ranaviruses are known to infect different classes of lower vertebrates including amphibians, fishes and reptiles. Differences in the likelihood of infection among ectothermic vertebrate hosts could explain the successful yearlong persistence of ranaviruses in aquatic environments. The goal of this study was to determine if transmission of a Frog Virus 3 (FV3)-like ranavirus was possible among three species from different ectothermic vertebrate classes: Cope's gray treefrog (Hyla chrysoscelis) larvae, mosquito fish (Gambusia affinis), and red-eared slider (Trachemys scripta elegans). We housed individuals previously exposed to the FV3-like ranavirus with naïve (unexposed) individuals in containers divided by plastic mesh screen to permit water flow between subjects. Our results showed that infected gray treefrog larvae were capable of transmitting ranavirus to naïve larval conspecifics and turtles (60% and 30% infection, respectively), but not to fish. Also, infected turtles and fish transmitted ranavirus to 50% and 10% of the naïve gray treefrog larvae, respectively. Nearly all infected amphibians experienced mortality, whereas infected turtles and fish did not die. Our results demonstrate that ranavirus can be transmitted through water among ectothermic vertebrate classes, which has not been reported previously. Moreover, fish and reptiles might serve as reservoirs for ranavirus given their ability to live with subclinical infections. Subclinical infections of ranavirus in fish and aquatic turtles could contribute to the pathogen's persistence, especially when highly susceptible hosts like amphibians are absent as a result of seasonal fluctuations in relative abundance.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphibians / virology*
  • Animals
  • DNA Virus Infections / transmission
  • DNA Virus Infections / veterinary*
  • DNA Virus Infections / virology
  • Ecology
  • Fishes / virology*
  • Larva / virology*
  • Ranavirus / pathogenicity*
  • Species Specificity
  • Turtles / virology*

Grants and funding

Funding for this research was provided by The University of Tennessee (UT) Institute of Agriculture through an AgResearch Access and Diversity Fellowship, UT College of Agricultural Sciences and Natural Resources via Hazelwood and the UT-ESPN Scholarships, and the Society of Wetland Scientists, Student Research Award. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.