Abstract
Fibropapillomatosis (FP) is a transmissible disease characterized by neoplastic growths that may be debilitative or even fatal.1 In green sea turtles (Chelonia mydas), FP is an important disease that reached panzootic proportions in recent decades.2 Direct horizontal transmission of chelonid herpesvirus 5 (ChHV5), the presumed etiologic agent of FP, was demonstrated experimentally when cell-free tumor extracts were shown to transmit FP to uninfected turtles.3,4 Phylogenetic data support the hypothesis that turtles are infected with ChHV5 after they arrive in neritic habitats as juveniles; however, it is also possible that ChHV5 transmission could occur vertically (mother to embryo) or horizontally on the natal beach (maternal shedding).5 The objectives of this study were to assess paired biological samples for indicators of vertical transmission of ChHV5 in green turtles in Florida, and to compare blood health parameters between adult female green turtles with and without evidence of ChHV5 infection. We evaluated blood samples taken from 60 FP-free, nesting female green turtles encountered on Juno and Jupiter Beach, Florida during 2017, and from 388 of the hatchlings that emerged from their nests, using a probe-based quantitative polymerase chain reaction (qPCR) targeting ChHV5 DNA.6 For the nesting females, 26/60 (43.33%) samples tested positive for ChHV5 DNA; analyses of hatchling samples are ongoing and results will be presented. These data may lend support to the hypothesis that ChHV5 can be transmitted vertically before or during oviposition. Blood health data (complete blood counts with differentials, plasma biochemistry and protein electrophoresis) for nesting female turtles that tested positive for ChHV5 were compared to data for turtles that tested negative for ChHV5 using Mann-Whitney U-tests with a Bonferroni correction. In turtles with ChHV5 DNA-positive blood samples, concentrations of a1 globulins were significantly higher (p = 0.004) than in samples from turtles with ChHV5 DNA-negative blood. These data indicate that nesting female green turtles with evidence of ChHV5 DNAemia have relative increases in their immune response, including acute phase proteins, which may be related to an inflammatory and/or infectious process involving subclinical ChHV5 infection.
Acknowledgements
We thank Loggerhead Marinelife Center for providing the technical support to collect and analyze the blood samples. This project was funded in part by a grant awarded from the Sea Turtle Grants Program. The Sea Turtle Grants Program is funded from proceeds from the sale of the Florida Sea Turtle License Plate. Learn more at www.helpingseaturtles.org/. We also thank the Harbor Branch Oceanographic Institute Foundation and the Florida Save Our Seas license plate fund grant, as well as the American Association for Zoo Veterinarians’ Wild Animal Health Fund, for financial support of this project.
* Presenting author
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