Bacteraemia in free-ranging Hawaiian green turtles Chelonia mydas with fibropapillomatosis

Abstract

Past studies of free-ranging green turtles Chelonia mydas with fibropapillomatosis (FP) in Hawaii have shown that animals become immunosuppressed with increasing severity of this disease. Additionally, preliminary clinical examination of moribund turtles with FP revealed that some animals were also bacteraemic. We tested the hypothesis that bacteraemia in sea turtles is associated with the severity of FP. We captured free-ranging green turtles from areas in Hawaii where FP is absent, and areas where FP has been endemic since the late 1950s. Each turtle was given an FP severity score ranging from 0 (no tumours) to 3 (severely affected). A fifth category included turtles that were stranded ashore and moribund with FP. We found that the percentage of turtles with bacteraemia increased with the severity of FP, and that the majority of bacteria cultured were Vibrio spp. Turtles with severe FP were more susceptible to bactaeremia, probably in part due to immunosuppression. The pattern of bacteraemia in relation to severity of disease strengthens the hypothesis that immunosuppression is a sequel to FP.

Retrospective pathology survey of green turtles Chelonia mydas with fibropapillomatosis in the Hawaiian Islands, 1993-2003

“…A similar pattern was seen in affected turtles near death (stranded turtles) in this study, suggesting that FP detrimentally affects survival in juveniles. This is corroborated by physiologic findings in non-stranded juvenile and subadult turtles that have revealed immunosuppression and bacteraemia in turtles that are tumor score 2 and above (Work et al 2001(Work et al , 2003.Populations of nesting females at French Frigate Shoals have been increasing (Balazs & Chaloupka 2004), and prevalence and case severity of FP in nesting female adult turtles is much lower than that in juveniles (Balazs & Pooley 1991). Lower prevalence of FP in adults can be explained by mortality prior to adulthood or ability of adults and subadults to recover from disease.…”

Tissue loss (white syndrome) in the coral Montipora capitata is a dynamic disease with multiple host responses and potential causes

“…Immunologically compromised hosts can at times be susceptible to invasion by single or multiple organisms. For example, humans infected with AIDS often have multiple fungal and bacterial infections [46], and sea turtles with fibropapillomatosis that are immunosuppressed have heavy infections with parasites and bacteria [47,48]. However, tools to understand coral immunology are limited [49].…”

Relationship between fibropapillomatosis and environmental quality: a case study with Chelonia mydas off Brazil

“…FP is associated with a herpesvirus (Herbst 1994, Quackenbush et al 1998, but the role of this agent in causing disease has not been clarified, and it appears other, as yet unidentified, factors probably play a role. It is known that turtles afflicted with FP have higher parasite loads (Work et al 2005), are immunosuppressed (Work et al 2001) and bacteraemic (Work et al 2003).…”

“…FP is associated with a herpesvirus (Herbst 1994, Quackenbush et al 1998, but the role of this agent in causing disease has not been clarified, and it appears other, as yet unidentified, factors probably play a role. It is known that turtles afflicted with FP have higher parasite loads (Work et al 2005), are immunosuppressed (Work et al 2001) and bacteraemic (Work et al 2003).Considerable geographical variation in the prevalence of FP exists (0 to 92%), and substantial differences may be found even between relatively close areas (Ehrhart 1991, Herbst 1994, Hirama & Ehrhart 2007. In addition to geographic variation, there is also variation in severity and nature of the disease as determined by size, location, and quantity of tumors (Adnyana et al 1997, Work & Balazs 1999, Hirama & Ehrhart 2007.…”