Green turtle fibropapillomatosis: challenges to assessing the role of environmental cofactors.

Abstract

Green turtle fibropapillomatosis (GTFP) is a growing threat to the survival of green turtle (Chelonia mydas) populations worldwide. Recent transmission studies point to an infectious etiology. Several field studies suggest that high GTFP prevalence is associated with marine habitats that have been impacted by agricultural, industrial, or urban development. Environmental contaminants could be involved in GTFP through several plausible mechanisms including cocarcinogenesis and contaminant-induced immune suppression. However, an association of contaminants with GTFP has not been established. A broader perspective is needed when studying infectious diseases such as GTFP in complex ecosystems. Alternative explanations for high GTFP prevalence in some near-shore habitats include the following: a) these habitats provide an optimum physical environment for survival and transmission of the infectious agent; b) these habitats attract a high density of susceptible turtles or harbor a higher density of potential vectors, facilitating transmission of the pathogen in a density-dependent fashion; and c) these habitats may contain other stressors that render turtles more susceptible to GTFP. Application of scientifically rigorous criteria in the epizootiology of GTFP in free-ranging populations remains a formidable challenge. -Environ Health Perspect 1 03(Suppl 4): 27-30 (1995)

Rise and Fall over 26 Years of a Marine Epizootic in Hawaiian Green Sea Turtles

“…An emerging worldwide threat to green turtles is fibropapillomatosis (Herbst, 1994), which is a pandemic disease associated with the presence of herpesviruses (Greenblatt et al, 2005).…”

“…Fibropapillomatosis (FP) is a neoplastic disease involving tumors in multiple cutaneous sites and connective tissue tumors in the viscera (Herbst, 1994;Fig. 1A).…”

“…Fibropapillomatosis prevalence has apparently increased over the past 2-3 decades in green turtle populations in Australia, Indonesia, and the US (Herbst, 1994;Chaloupka and Balazs, 2005;Foley et al, 2005;Greenblatt et al, 2005). It is believed that FP might impair recovery of depleted populations (Herbst, 1994;Ene et al, 2005), especially the green turtle stock endemic to Hawaii (Balazs and Chaloupka, 2004;Chaloupka and Balazs, 2005). Despite a global distribution and high prevalence in some populations (Herbst, 1994), there has been no longterm assessment of FP for any marine turtle population (Chaloupka and Balazs, 2005).…”

“…It is believed that FP might impair recovery of depleted populations (Herbst, 1994;Ene et al, 2005), especially the green turtle stock endemic to Hawaii (Balazs and Chaloupka, 2004;Chaloupka and Balazs, 2005). Despite a global distribution and high prevalence in some populations (Herbst, 1994), there has been no longterm assessment of FP for any marine turtle population (Chaloupka and Balazs, 2005). Long-term assessments of the prevalence of major chronic diseases like FP in marine vertebrates are critically needed to improve our understanding of marine disease epizootiology (Harvell et al, 1999).…”

“…This population has the highest recorded FP prevalence in the Hawaiian Archipelago (Balazs and Chaloupka, 2004;Chaloupka and Balazs, 2005), where the disease is endemic (Herbst, 1994). Annual disease monitoring was based on a capture-markrecapture program, where each turtle was marked with metal flipper and/or passive integrated transponder tags (Balazs and Chaloupka, 2004;Chaloupka and Balazs, 2005).…”