Spiorchiidae Infections in Sea Turtles Stranded on Taiwan

            Spirochiidae fluke infections of sea turtles are very high, and may be the cause the death of infected sea turtles all over the world. Chen et al. (2012) examined thirty green turtles, Chelonia mydas, and two loggerhead turtles, Carreta caretta, that were found stranded and dead off of the coast of Taiwan. The causes of death for many of those turtles were determined to be related to fishing incidents, but they were all examined for spirochiidae eggs and adult flukes. The stranded sea turtles were found to be infected with spirochiidae flukes, and the pathological response was examined as much as possible considering the decomposition levels of the turtles. Any suspected infected organs were rinsed with water and screened with mesh to isolate adult flukes (Chen et al., 2012). The authors isolated any spirorchiidae eggs from the tissues through homogenization using a mortar and pestle.

Chen et al. (2012) found flukes in the turtles’ hearts that were causing arterial inflammation and thromboses. The thromboses were found in very severe cases and were composed of mixed eggs, egg fragments, eosinophilic debris and mononuclear cells. The eggs were disseminated to various organs such as the liver, lung, spleen and gastrointestinal tract where they induced granulomas.  There was even signs of spirorchiidiasis in hosts where there were no adult flukes found. It was hypothesized that the amount of decomposition in those cases resulted in the loss of the adult flukes but retained the eggs because they are sturdier and harder to wash away (Chen et al., 2012). The adult flukes that were found and several species were identified to the species level and several were found, including Learedius learedi.

The observed pathology of turtles showed a similar eggs distribution in organs that is present in infected turtles from other countries. Many previous studies suggest that spirochiidae infections play an important role in stranding and mortality of sea turtles although Chen et al. (2012) found that to be inconclusive in this study.  The causes of death of the examined sea turtles were probably not directly related to the spirorchiid infection which was determined by signs on the bodies that were indicative of being fishing related. This study gives a measure of the prevalence of spirorchiid infections in green turtles in Tawain (Chen et al., 2012). More studies in the future would give a greater understanding of the prevalence of fluke infections in relation to potentially significant topics such as the season and the species, gender and age of sea turtles.

Chen et al. (2012) presented research that expanded on the pathology of spirochiidae infections in sea turtles. The article expanded on knowledge already accumulated about parasitic infections of sea turtles. More specifically, it creates a comparison between the pathology of an ectoparasite and an endoparasite of sea turtles. Badillo et al. (2006) briefly mentions the pathology of Balaenophilus on sea turtles. The very noticeable pathology was on one heavily infected individual that was caused by several hundred individuals of Balaenophilus and it was isolated to the one area. Chen et al. (2012) looked into a parasite that lives within a host, and has much fewer numbers. Comparing the two pathologies, the internal pathology caused by a fluke is significantly worse than the pathology caused by Balaenophilus. Chen et al. (2012) also expand upon the article by Stacy et al. (2010) which introduced an intermediate host for Learedius learedi. Both articles deal with spirorchiid trematodes of sea turtles, and contribute to a growing knowledge about a parasite that is endangering sea turtles worldwide.

Works Cited:

Badillo, F.J., L. Puig, F.E. Montero, J.A. Raga, F.J. Aznar. 2006. Diet of Balaenophilus spp. (Copepoda: Harpacticoida): feeding on keratin at sea? Marine Biology 151: 751 – 758.

Chen, H., R.-J. Kkueo, T.-C. Chang, C.-K. Hus, R.A. Bray and I.-J. Cheng. 2012. Fluke (Spirorchiidae) Infections in Sea Turtles Stranded on Taiwan: Prevalence and Pathology. The Journal of Parasitology 98 (2): 437 – 439.

Stacy, B.A., T. Frankovich, E. Greiner, A.R. Alleman, L.H. Herbst, P. Klein, A. Bolton, A. McIntosh and E.R. Jacobson. 2010. Detection of spirorchiid trematodes in gastropod tissue by polymerase chain reaction: preliminary identification of an intermediate host of Learedius learedi. The Journal of Parasitology 96 (4): 752 – 757.