Rudolfová J. (2002): Trichobilharzia ocellata versus T. szidati - a solved riddle? 11. Helmintologické dny, Dolní Věstonice, 13.-16. května 2002. In: Helminthologia 39, 3: 179.

0440-6605,

IF 0,793

Trichobilharzia ocellata is a type species of the genus Trichobilharzia. It was described in the stage of cercariae as Cercaria ocellata La Valette, 1855 from Lymnaea stagnalis in Berlin area, Germany. Brumpt (1931) realized the life cycle and placed the adults into the genus Trichobilharzia. There were reports of C. ocellata from other snail species (Radix ovata, Planorbarius corneus, Stagnicola palustris, etc.) and from other regions (France, Great Britain, Canada, USA, Japan, Russia) during the 20th century. Szidat concluded that T. ocellata is a complex of species and established three new species: C. neocellata Szidat, 1934; C. pseudocellata Szidat, 1942 and C. parocellata Szidat, 1942. Neuhaus found that C. parocellata was already described in 1939 and renamed it as C.(T.) szidati Neuhaus, 1952. However, some authors considered T. szidati as synonymous to T. ocellata. Later, several species were excluded from T. ocellata complex (T. franki Müller et Kimmig, 1994 from Radix auricularia in Germany and T. regenti Horák, Kolářová et Dvořák, 1998 from R. peregra in the Czech Republic).
Both LaValette's (1855) and Brumpt's (1931) descriptions are insufficient to determine cercariae or other developmental stages. Thus, it is not clear which trichobilharzians have been observed by the authors. It is necessary to assign the name T. ocellata to one concrete species of the complex, and the most related one is probably T. szidati Neuhaus, 1952. However, some authors reported differences between T. szidati and T. ocellata, and thus, the comparison of these two species needs to be done.
As cercarial characters are insufficient for comparison, sequencing of ITS region of rDNA and mitochondrial COI gene were performed. Cercarial DNA samples isolated from wild and laboratory T. szidati strains from the Czech Republic and from the laboratory strains of T. ocellata from Germany and the Netherlands were compared. Sequence of T. regenti was used as an outgroup.
Preliminary results suggest T. szidati to be identical to T. ocellata, but additional analysis is required to compare the variability of other Trichobilharzia species with that between T. szidati and T. ocellata strains. Comparison of life cycles and developmental stages of both species is also necessary.

Trichobilharzia ocellata; Schistosomatidae; T. regenti; Tichobilharzia scidati