title: Further evidence of Chelonid herpesvirus 5 (ChHV5) latency: high levels of ChHV5 DNA detected in clinically healthy marine turtles.
abstract: The Chelonid herpesvirus 5 (ChHV5) has been consistently associated with fibropapillomatosis (FP), a transmissible neoplastic disease of marine turtles. Whether ChHV5 plays a causal role remains debated, partly because while FP tumours have been clearly documented to contain high concentrations of ChHV5 DNA, recent PCR-based studies have demonstrated that large proportions of asymptomatic marine turtles are also carriers of ChHV5. We used a real-time PCR assay to quantify the levels of ChHV5 Glycoprotein B (gB) DNA in both tumour and non-tumour skin tissues, from clinically affected and healthy turtles drawn from distant ocean basins across four species. In agreement with previous studies, higher ratios of viral to host DNA were consistently observed in tumour versus non-tumour tissues in turtles with FP. Unexpectedly however, the levels of ChHV5 gB DNA in clinically healthy turtles were significantly higher than in non-tumour tissues from FP positive turtles. Thus, a large proportion of clinically healthy sea turtle populations worldwide across species carry ChHV5 gB DNA presumably through persistent latent infections. ChHV5 appears to be ubiquitous regardless of the animals' clinical conditions. Hence, these results support the theory that ChHV5 is a near ubiquitous virus with latency characteristics requiring co-factors, possibly environmental or immune related, to induce FP.
authors.affiliation: Section for Evolutionary Genomics, Center for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen K, Denmark; Laboratorio de Biomedicina, Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador.
authors.forename: Alonzo
authors.initials: A
authors.lastname: Alfaro-Núñez
authors.affiliation: Department of Veterinary Disease Biology, Veterinary Clinical Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen , Frederiskberg , Copenhagen , Denmark.
authors.forename: Anders Miki
authors.initials: AM
authors.lastname: Bojesen
authors.affiliation: Center for Zoo and Wild Animal Health, Copenhagen Zoo , Frederiskberg , Copenhagen , Denmark.
authors.forename: Mads F
authors.initials: MF
authors.lastname: Bertelsen
authors.affiliation: Section for Evolutionary Genomics, Center for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen , Copenhagen K , Denmark.
authors.forename: Nathan
authors.initials: N
authors.lastname: Wales
authors.affiliation: Pacific Islands Fisheries Science Center, National Marine Fisheries Service , Honolulu , HI , United States of America.
authors.forename: George H
authors.initials: GH
authors.lastname: Balazs
authors.affiliation: Section for Evolutionary Genomics, Center for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen K, Denmark; Trace and Environmental DNA Laboratory, School of Environment and Agriculture, Curtin University of Technology, Perth, Perth, Australia.
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
keywords: Asymptomatic; Chelonid herpesvirus 5 (ChHV5); Clinically healthy; Fibropapillomatosis (FP); Glycoprotein B; Quantitative PCR; Ubiquitous; Viral loads