A pilot study on molecular diagnosis of Hapalotrema mistroides (Digenea: Spirorchiidae) infection in blood samples of live loggerhead turtles Caretta caretta

Abstract

Background: Parasites of the family Spirorchiidae cause disease and mortality in marine and freshwater turtles; two species, Hapalotrema mistroides and Neospirorchis sp., are reported in the resident population of loggerhead turtles of the Mediterranean Sea, with the first being the most widespread. In vivo diagnosis of spirorchidiasis can represent a challenge in guaranteeing prompt control and treatment of the disease and is currently limited to copromicroscopy. The aim of this study was the development of a real time PCR assay with TaqMan probe for the detection of H. mistroides infection in the blood of live loggerhead turtles, Caretta caretta, hospitalized in rehabilitation centres. Its potential use for in vivo diagnosis is explored. Results: The developed real time PCR successfully detected H. mistroides DNA from both positive controls and experimental blood samples of live loggerhead sea turtles, showing good specificity, sensitivity and good reaction efficiency. Two out of three turtles which had demonstrated positivity at copromicroscopy also tested positive to this blood assay; DNA of H. mistroides was detected within the blood of one sea turtle, which tested negative for copromicroscopy. Conclusions: This study describes a specific and rapid molecular assay to detect H. mistroides infection from live sea turtles and highlights for the first time the presence of DNA of this species in turtle blood samples. Since this assay is able to detect low amounts of the parasitic free DNA in blood samples, its application could be helpful for in vivo diagnosis of H. mistroides infection as well as for epidemiological purposes.

Case report: Blindness associated with Learedius learedi trematode infection in a green sea turtle, Chelonia mydas, of the northern Red Sea

“…Several species of sea turtles have been affected in various ocean basins. Severe fluke lesions have been reported in Florida (13,14), Hawaii (15), Costa Rica (16,17), Brazil (18,19), and Italy (12,20), with Australia experiencing the highest prevalence and greatest mortality rates (21)(22)(23). This study reports the first case of Learedius learedi infection associated with bilateral blindness in a green sea turtle of the Northern Red Sea.…”

“…To date, the standard way to diagnose these parasites in live animals is based on the morphology of the eggs by copro-microscopy examination (10). However, in 2020, Marchiori et al demonstrated the need for more accurate methodologies and consequently developed a blood sample analysis method that provides improved precision (12).…”

The use of echocardiography as a health assessment tool in green sea turtles (Chelonia mydas)

“…Historically, the lack of reliable ante‐mortem diagnostic techniques to detect spirorchiid fluke infection has prevented an accurate determination of the true prevalence and morbidity of disease caused by the parasite 35 . Recent advances have succeeded in using molecular tools such as polymerase chain reactions to detect parasite DNA 36 ; however, direct ultrasonographical examination of the heart and major arteries, which is a site commonly inhabited by these parasites 33 , may enable real‐time, in‐field diagnosis of this disease. Combining this technique with traditional health assessments such as haematological and biochemical analyses, body condition metrics 2 and novel biomarkers capable of quantifying thromboembolic disease may improve the ability of researchers to monitor the health of wild populations and aid clinicians in the development of treatment protocols in animals undergoing rehabilitation.…”