Causes of mortality in green turtles from Hawaii and the insular Pacific exclusive of fibropapillomatosis

Work, Thierry M.; Balazs, George H.; Hapdei, Jessy R.; Tagarino, Alden

doi:10.3354/dao02890

Cited by 31 publications

(37 citation statements)

References 24 publications

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“…However, significant spirorchiid associated pathology was observed even in robust turtles, indicating that flukes may potentially act as primary pathogens rather than just secondary opportunists (Stacy et al, 2010a). In Hawaii, spirorchiid infections appear to increase with emaciation of the host (Work et al, 2005;Work et al, 2015).…”

Section: Generalmentioning

confidence: 99%

“…while spirorchiidiasis is often a primary cause of death in Australian sea turtles , it is less frequently fatal in turtles from the south-eastern United States (Stacy et al, 2010a), and Hawaii (Work et al, 2015). The reasons behind these geographic variations are unexplained.…”

Section: Introductionmentioning

confidence: 99%

“…Emaciation/cachexia is commonly reported in turtles with spirorchiid infection Glazebrook and Campbell, 1990;Glazebrook et al, 1981Glazebrook et al, , 1989Stacy et al, 2010a;Work et al, 2015).…”

Section: Clinical Signsmentioning

confidence: 99%

“…Infectious diseases are a major cause of mortality Meager and Limpus, 2012;Work et al, 2004;Work et al, 2015). Their occurrence appears to vary spatially and temporally, though our understanding of the driving factors behind these fluctuations is limited.…”

Section: Introductionmentioning

confidence: 99%

“…A study of causes of death in turtles between 2006 and 2009 found that spirorchiidiasis was the most common cause (41.8%) of mortality in Queensland green sea turtles . Spirorchiids maintain a high infection rate in turtles globally, including regions such as Hawaii (Aguirre et al, 1998;Graczyk et al, 1995;Work et al, 2005;Work et al, 2015), the eastern United…”

Section: Introductionmentioning

confidence: 99%

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Diversity, impacts and diagnosis of pathogenic parasites in sea turtles from Queensland, Australia

Chapman¹

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Parasitism is a significant cause of stranding and mortality in endangered sea turtles. Two parasites in particular (or groups thereof) have been noted for their impacts on green sea turtle populations. The first are the spirorchiid blood flukes, which inhabit the circulatory systems of their host. The second is the eimeriid coccidian Caryospora cheloniae, a systemic parasite affecting a number of organs. Diversity among these organisms is poorly explored, and is almost certainly greater than currently recognised. The parasites and their associated diseases fluctuate both temporally and spatially in terms of prevalence and severity, however, the factors driving these fluctuations are poorly understood. A variety of questions remain unanswered in terms of the epidemiology and relative pathogenicity of the different parasite species. Of particular interest are brain lesions, which have been associated with both parasites and in some cases lead to neurological deficiency and subsequent mortality. Difficulties in finding answers to these questions is compounded by a lack of reliable, fast and quantitative ante-and post-mortem diagnostic tools for either parasite, which restricts their investigation.In order to catalogue local species and assess diversity, adult spirorchiid flukes were collected during post-mortem examination of deceased sea turtles and characterised by molecular and morphological means. Eleven distinct species or genotypes were identified, comprising a mix of previously described and novel species or variants. Samples were also collected from green sea turtles that died during a coccidiosis related mass mortality event in south east Queensland and northern New South Wales. While only one species of coccidian (C. cheloniae) had been previously described, molecular characterisation of the organism implicated in the outbreak revealed two distinct coccidian genotypes, which has significant implications for diagnosis and management.Spirorchiid ova have been associated with granulomatous lesions in a wide range of host tissues. However, it has not been possible to identify spirorchiids beyond the genus level based on morphology, which has frustrated any attempts to identify the species or variants responsible for severe lesions. In this thesis, a molecular approach was used and a terminal restriction fragment length polymorphism (T-RFLP) assay was developed to detect and identify individual species within the often mixed assemblages of ova in turtle tissues. This assay proved to be a more specific and sensitive alternative to traditional iii microscopic detection methods. Through correlation with histopathology and gross pathology, the tissue tropisms, relative occurrence and pathogenicity of each species were investigated. The most common species (Neospirorchis Genotype 2) was found in 96% of samples, encompassing tissues from all organs sampled. On average, a greater number of spirorchiid species were detected in tissues where lesions were present, and numbers increased along with the severity o...

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Section: Generalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Clinical Signsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diversity, impacts and diagnosis of pathogenic parasites in sea turtles from Queensland, Australia

Chapman¹

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Spatio‐temporal distribution of sea turtle strandings and factors contributing to their mortality in south‐eastern Brazil

Tagliolatto

Goldberg

Godfrey

et al. 2019

Aquatic Conservation

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Data on stranded sea turtles were examined between 2010 and 2016 along the northern region of Rio de Janeiro state and between 2016 and 2017 in the southern region, looking for spatio‐temporal patterns and determining which factors contributed to their mortality. A total of 12,162 strandings of all five species that occur in Brazil were recorded, with Chelonia mydas being the most common (89.9%). Sea turtles use the Rio de Janeiro coast as a feeding and/or migration area. The intense upwelling (October to April) may be an important factor for the sea turtles feeding in this region, mainly for Eretmochelys imbricata and Dermochelys coriacea, which had a higher number of strandings during this period. Areas further north of the study area include an important nesting site for Caretta caretta in Brazil, which explains the higher concentration of strandings of subadults/adults of this species in this region and during its nesting season. Many anthropogenic threats to sea turtles were documented, mainly incidental capture in fisheries and marine debris, indicating possible hotspots for these threats in the regions of Sepetiba and Guanabara Bays, Cabo Frio, and São Francisco de Itabapoana. Among the natural causes of strandings, the primary factors were chronic illness, endoparasites, and fibropapillomatosis. However, pollution may also be an indirect threat, which negatively affects these animals through reduced health and immunosuppression, leaving them more susceptible to opportunistic diseases. These data are valuable for directing and implementing specific and local mitigation measures along the Rio de Janeiro state coast, such as avoiding bycatch hotspots through fleet communication programmes and/or area and seasonal closures, enforceable legislation, effective penalties and proper waste management.

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Moleón

Selva

Quaggiotto

et al. 2019

Wildlife Research Monographs

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Causes of mortality in green turtles from Hawaii and the insular Pacific exclusive of fibropapillomatosis

Cited by 31 publications

References 24 publications

Diversity, impacts and diagnosis of pathogenic parasites in sea turtles from Queensland, Australia

Diversity, impacts and diagnosis of pathogenic parasites in sea turtles from Queensland, Australia

Spatio‐temporal distribution of sea turtle strandings and factors contributing to their mortality in south‐eastern Brazil

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