Differences in Antibody Responses against Chelonid Alphaherpesvirus 5 (ChHV5) Suggest Differences in Virus Biology in ChHV5-Seropositive Green Turtles from Hawaii and ChHV5-Seropositive Green Turtles from Florida

Abstract

Fibropapillomatosis (FP) is a tumor disease associated with chelonid herpesvirus 5 (ChHV5) that is an important cause of mortality in threatened green turtles globally. FP is expanding in Florida and the Caribbean but declining in Hawaii. We show that Hawaiian turtles mount antibodies to ChHV5 mainly in response to tumors, which are the only sites of viral replication, whereas tumored and nontumored Floridian turtles are uniformly seropositive. Tumor viruses that depend on tumors for replication and spread are rare, with the only example being the retrovirus causing walleye dermal sarcoma in fish. The Hawaiian strain of ChHV5 may be the first DNA virus with such an unusual life history. Our findings, along with the fundamental differences in the life histories between Floridian turtles and Hawaiian turtles, may partly explain the differential dynamics of FP between the two regions.