Dr. Murai Éva szerk.: Parasitologia Hungarica 24. (Budapest, 1991)

Parasit hung. 24:53-58,1991 © Hungarian Society of Parasitologists Sphaerospora danubialis sp. n. (Myxosporea: Sphaerosporidae) from the kidney of freshwater pereid fishes K. MOLNÁR

1 Abstract: Sphaerospora danubialis sp. n. is a common parasite of striped ruffe (Gymnocephalus schraetzef), ruffe (G. cemua) and pikeperch (Stizostedion lucioperca) of the River Danube. Its spores inhabiting the renal tubules morphologically differ from those of S. markewitschi and 5. pectinacea, the already known sphaerospores of freshwater percids. Besides sporogonic stages in the renal tubules, presporogonic stages in the blood were found in striped ruffe. Key words: Myxosporea, Sphaerosporidae, Sphaerospora danubialis, taxonomy, pereid fishes, new species, spores, blood stages, Danube. INTRODUCTION Myxosporeans belonging to the genus Sphaerospora have recently commanded increasing interest because of their rather high pathogenicity on the one hand and their unique developmental cycle on the other. Lom et al. (1989) reported on 42 known species. Of them, Sphaerospora tincae (the agent of head kidney swelling in tench), S. renicola (the causative agent of swimbladder inflammation in common carp) and the gill parasite S. molnári are expressly pathogenic parasites. The PKX parasite described from salmonids, which Kent and Hedrick (1986) regard as a developmental stage of a renal sphaerospore, also has great economic importance. According to Csaba et al. (1984), in the development of S. renicola the sporogonic stage is preceded by a blood and a tissue stage. During the blood stage, the blood of fish contains an extracellular Sphaerospora stage (Csaba 1976; Lom et al. 1983) in which eight daughter cells develop by internal cleavage. In the swimbladder of the common carp the blood stages become primary cells enclosing about 40 daughter cells (Kovács-Gayer et al. 1982). In these primary cells triple formations (one secondary cell containing two tertiary cells) develop which get through the renal glomeruli into the convoluted tubules and change into pseudoplasmodia containing sporoblasts and spores (Molnár and Kovács-Gayer 1986). Blood stages containing 1 Veterinary Medical Research Institute, Hungarian Academy of Sciences, Budapest, Hungary