Diplostomum species

Ubels, John L., DeJong, Randall J., Hoolsema, Brittany, Wurzberger, Amy, Nguyen, Thuy-Tien, Blankespoor, Harvey D. & Blankespoor, Curtis L., 2018, Impairment of retinal function in yellow perch (Perca flavescens) by Diplostomum baeri metacercariae, International Journal for Parasitology: Parasites and Wildlife 7 (2), pp. 171-179 : 175

4.2. Diplostomum species in Douglas Lake

In recent years several investigators have used DNA sequencing techniques to investigate Diplostomum species diversity in various aquatic systems in ( Behrmann-Godel, 2013; Désilets et al., 2013, Locke et al., 2010b; Locke et al., 2015). The species identified in the lens in our study agree with reports by Désilets et al. (2013), Locke et al. (2010a,b) and Locke et al. (2015) that Diplostomum sp.1 , sp.3, and sp.4 appear to be generalists, infecting multiple species and choosing the lens, an immunologically-safe site. Our data also update previous reports that the species inhabiting Douglas Lake is Diplostomum flexicaudum ( Cort et al., 1937; Keas and Blankespoor, 1997), a name not found in more recent publications.

The identification of Diplostomum baeri as the only species infecting perch in Douglas Lake and strongly preferring the choroid, is consistent with previous observations that Diplostomum baeri is a specialist in yellow perch and targets a specific tissue type ( Désilets et al., 2013; Locke et al., 2010a,b; Locke et al., 2015). Our identification, using molecular techniques, of Diplostomum baeri in tissues associated with the yellow perch retina also updates a previous report, based only on morphology, that the species infecting the retinas of yellow perch is Diplostomum adamsi ( Lester and Huizinga, 1977) . The report that cutthroat trout ( Salmo clarki ) retinas are infected by Diplostomum baeri ( Heckmann and Ching, 1987; Dwyer and Smith, 1989) has not been confirmed by DNA sequencing. It has also been reported by Höglund and Thulin (1992) and Behrmann-Godel, 2013 that Diplostomum baeri infects the eye of the European perch ( Perca fluviatalis ) which is closely related to the North American yellow perch. This identification of Diplostomum baeri must be approached with caution, since Georgieva et al. (2013) have shown that the European Diplostomum baeri is a species complex and is different than the North American species ( Locke et al., 2015). None the less, it is interesting that the European Diplostomum baeri is also confined, according to Höglund and Thulin (1992), to the retinal tissue of a perch.