Investigating Chelonid Fibropapilloma-Associated Herpesvirus in Symptomatic and Asymptomatic Rehabilitating Green Sea Turtles (Chelonia mydas)
Fibropapillomatosis (FP) is the most important infectious disease of sea turtles, particularly green sea turtles (Chelonia mydas). Fibropapillomatosis tumors, characterized by cutaneous, conjunctival, and visceral growths, often debilitate affected turtles by impeding feeding, movement and vision, and/or leading to organ failure. Chelonid fibropapilloma-associated herpesvirus (CFPHV) is consistently associated with FP tumors and has also been identified in clinically normal turtles, likely representing early or subclinical infection. In this study, we develop and apply molecular techniques to better understand the virus-host pathosystem of CFPHV, and to investigate the role of cell type in symptomatic and asymptomatic CFPHV infections. This is a comparative study of juvenile, wild-caught green sea turtles in rehabilitation facilities throughout eastern Florida and Georgia, USA. Presence/absence of CFPHV is evaluated using quantitative polymerase chain reaction (qPCR) and serological screening, and turtles are designated as symptomatically/asymptomatically infected or uninfected. Assaying for CFPHV DNA using qPCR, we explore cell type(s) infected, extent of virus replication, and viral loads in various biological samples, including FP tumors, skin, mucosae, blood, feces, urine, nervous tissues, and organs. Further inquiry includes evaluating the environment’s role in CPFHV prevalence by assaying tank filter and water samples for CFPHV DNA, as well as seawater and sea grass sampled from local green sea turtles’ natural habitats. Understanding characteristics of subclinical infection will allow for better identification of biological factors leading to viral transmission, and it will help optimize detection and control strategies for FP in natural and captive settings.