“Sphaerosporosis”, a New Kidney Disease of the Common Carp

Abstract

Parasitological surveys of cultured one-summer carp often revealed the presence of spores and developing stages of the myxosporidium Sphaerospora angulata Fujita, 1912 in renal tubules (Molnár, 1980). The rate of S. angulata invasion was especially high in fish stocks also affected by other parasitic or nonparasitic diseases (blood protozoans, gill sphaerosporosis, swim bladder disease). This prompted closer investigations into carp renal sphaerosporosis, a disease not previously known in Europe. The study covered the following aspects: (1) nature of renal lesions caused by S. angulata; (2) possible identity of the extracellular blood sporozoan of unknown systematic position described by Csaba (1976) with a developmental stage ofS. angulata; (3) etiological responsibility of one or two different Sphaerospora spp. for the gill and kidney sphaerosporosis of carp; (4) possible causal involvement of S. angulata in the etiologically unknown swim bladder disease associated with swelling of the kidnev.