Disease risk analysis in sea turtles: A baseline study to inform conservation efforts

Abstract

The impact of a range of different threats has resulted in the listing of six out of seven sea turtle species on the IUCN Red List of endangered species. Disease risk analysis (DRA) tools are designed to provide objective, repeatable and documented assessment of the disease risks for a population and measures to reduce these risks through management options. To the best of our knowledge, DRAs have not previously been published for sea turtles, although disease is reported to contribute to sea turtle population decline. Here, a comprehensive list of health hazards is provided for all seven species of sea turtles. The possible risk these hazards pose to the health of sea turtles were assessed and “One Health” aspects of interacting with sea turtles were also investigated. The risk assessment was undertaken in collaboration with more than 30 experts in the field including veterinarians, microbiologists, social scientists, epidemiologists and stakeholders, in the form of two international workshops and one local workshop. The general finding of the DRA was the distinct lack of knowledge regarding a link between the presence of pathogens and diseases manifestation in sea turtles. A higher rate of disease in immunocompromised individuals was repeatedly reported and a possible link between immunosuppression and environmental contaminants as a result of anthropogenic influences was suggested. Society based conservation initiatives and as a result the cultural and social aspect of interacting with sea turtles appeared to need more attention and research. A risk management workshop was carried out to acquire the insights of local policy makers about management options for the risks relevant to Queensland and the options were evaluated considering their feasibility and effectiveness. The sea turtle DRA presented here, is a structured guide for future risk assessments to be used in specific scenarios such as translocation and head-starting programs.

The Concurrent Detection of Chelonid Alphaherpesvirus 5 and Chelonia mydas Papillomavirus 1 in Tumoured and Non-Tumoured Green Turtles

“…Despite the noted limitations, the results reported in the present study show some clear and reliable trends which we hope will be further explored on a global scale. Our understanding of FP, and marine turtle virology as a whole, has many knowledge gaps [ 1 ] which need to be addressed in order to develop comprehensive management plans for these endangered species. The results from this and other studies have revealed that viral DNA is present in animals that do not show clinical signs [ 18 , 56 , 58 ], which questions their role in tumour development and highlights the need for further understanding of co-factors (environmental triggers, host genetics and immune responses) in disease development and why some turtles do not develop tumours despite the presence of viral DNA.…”

“…The endangered green turtle ( Chelonia mydas ) faces many threats, each of which need to be effectively managed in order to conserve this vulnerable species. Although the impact of disease in wild populations is largely unknown [ 1 ], green turtles are particularly susceptible to a tumour-forming disease [ 2 ]. Fibropapillomatosis (FP) is a neoplastic disease characterised by the formation of benign tumours.…”

“…It is clear that the role of papillomaviruses in FP and the fact that viruses are the least studied pathogens in marine turtles [ 1 ] warrant further investigation. The overall objective of the current study was to conduct a comprehensive molecular survey to better understand the disease ecology.…”

Rediscovering Kemp’s Ridley Sea Turtle (Lepidochelys kempii): Molecular Analysis and Threats

“…Of the studies on female kemps ridley movements between nesting events, information is only available for three individuals. These studies found that after nesting one tagged female travelled north [29] from the main nesting site at Rancho Nuevo Sanctuary; two turtles have travelled south from Rancho Nuevo with one covering a distance of ~100 km Further studies are required to understand Kemps ridley movements between nesting events.…”

“…Examples of these parasites are for bacteria: Vibrio spp. Pseudomonas spp., Enterococcus spp., Aeromonas, Cytophaga, and others; for fungi: Fusarium species Fusarium solani, Fusarium oxysporum, F. solani, and Pseudallescheria boydii Fusarium keratoplasticum; and viruses manly Herpesviridae [29]. In turn, they risk spreading diseases when in contact with other species or populations.…”