6Lisbon Oceanarium, 1999-005 Lisbon, Portugal A global phylogeny for chelonid fibropapilloma-associated herpesvirus (CFPHV), the most likely aetiological agent of fibropapillomatosis (FP) in sea turtles, was inferred, using dated sequences, through Bayesian Markov chain Monte Carlo analysis and used to estimate the virus evolutionary rate independent of the evolution of the host, and to resolve the phylogenetic positions of new haplotypes from Puerto Rico and the Gulf of Guinea. Four phylogeographical groups were identified: eastern Pacific, western Atlantic/eastern Caribbean, mid-west Pacific and Atlantic. The latter comprises the Gulf of Guinea and Puerto Rico, suggesting recent virus gene flow between these two regions. One virus haplotype from Florida remained elusive, representing either an independent lineage sharing a common ancestor with all other identified virus variants or an Atlantic representative of the lineage giving rise to the eastern Pacific group. The virus evolutionary rate ranged from 1.62¾10 "4 to 2.22¾10 "4 substitutions per site per year, which is much faster than what is expected for a herpesvirus. The mean time for the most recent common ancestor of the modern virus variants was estimated at 192.90-429.71 years ago, which, although more recent than previous estimates, still supports an interpretation that the global FP pandemic is not the result of a recent acquisition of a virulence mutation(s). The phylogeographical pattern obtained seems partially to reflect sea turtle movements, whereas altered environments appear to be implicated in current FP outbreaks and in the modern evolutionary history of CFPHV.
INTRODUCTIONChelonid fibropapilloma-associated herpesvirus (CFPHV) is the most likely aetiological agent of fibropapillomatosis (FP) (Arthur et al., 2008a;Greenblatt et al., 2005;Lackovich et al., 1999;Quackenbush et al., 1998), a neoplastic disease of sea turtles, characterized by recent outbreaks (Diez et al., 2010;Foley et al., 2005;Work & Balazs, 1999). The tumours can be both external and internal and, although benign, depending on location and size, they may obstruct crucial functions such as swimming, feeding and sight, or may impede organ function (Herbst, 1994;Herbst & Klein, 1995). Severe FP also leads to bacteraemia (Work et al., 2003). The most susceptible life stages appear to be neritic juveniles and subadults, whereas in adults the disease is rare (Ene et al., 2005;Herbst & Klein, 1995;Work et al., 2004). A high prevalence of FP is common in anthropogenically altered environments (Aguirre & Lutz, 2004;Herbst, 1994;Van Houtan et al., 2010), suggesting that factors in these environments promote disease outbreaks, for example, through the enhancement of virus transmissibility and/or the enhancement of disease expression via substances thatThe GenBank/EMBL/DDBJ accession numbers for the CFPHV sequences determined in this study are JN580279-JN580296 and JN625251-JN625262.Further details about samples are available with the online version of this paper. Phylogenies of herpesv...
