Persistent infectivity of a disease-associated herpesvirus in green turtles after exposure to seawater

Herpesviruses are associated with several diseases of marine turtles includ ing lung-eye-trachea disease (LETD) and gray patch disease (GPD) of green t urtles (Chelonia mydas) and fibropapillomatosis (FP) of green, loggerhead ( Caretta caretta), and olive ridley turtles (Lepidochelys olivacea). The sta bility of chelonian herpesviruses in the marine environment, which may infl uence transmission, has not been previously studied. In these experiments, LETD-associated herpesvirus (LETV) was used as a model chelonian herpesviru s to test viral infectivity after exposure to seawater. The LETV virus prep arations grown in terrapene heart (TH-1) cells were dialyzed for 24 to 120 hr against aerated artificial or natural seawater or Hank's balanced salt s olution (HBBS). Fresh TH-1 cells were inoculated with dialyzed LETV, and on day 10 post-infection cells were scored for cytopathic effect. Virus sampl es dialyzed up to 120 hr were positive for the herpesvirus DNA polymerase g ene by polymerase chain reaction. Electron microscopy revealed intact LETV nucleocapsids after exposure of LETV to artificial seawater or HBSS for 24 hr at 23 C. LETV preparations remained infectious as long as 120 hr in natu ral and artificial seawater at 23 C. Similar results were obtained with a s econd culturable chelonian herpesvirus, HV2245. LETV infectivity could not be detected after 48 hr exposure to artificial seawater at 30 C. Since LETV and HV2245 remain infectious for extended periods of time in the marine en vironment, it is possible that FP-associated and GPD-associated herpesvirus es also may be stable. These findings are significant both for researchers studying the epidemiological association of herpesviruses with diseases of marine turtles and for individuals who handle turtles in marine turtle cons ervation efforts.