Dr. Murai Éva szerk.: Parasitologia Hungarica 19. (Budapest, 1986)

Parasit, hang. 19. 1986 Observations on the intracellular and coelozoic developmental stages of Hoferellus cyprini (Doflein, 1898) (Myxosporea, Myxozoa) Dr. Kálmán MOLNÁR — Dr. Éva KOVÁCS-GAYER Veterinary Medical Research Institute of the Hungarian Academy of Sciences, Budapest — Central Veterinary Institute, Budapest, Hungary "Observations on the intracellular and coelozoic developmental stages of Hoferellus cyprini (Doflein, 1898} (Myxosporea, Myxozoa)" - Molnár, K. - KovácsGayer, É. - Parasit, hung., 19; 27-30. 1986. ABSTRACT. The release of intracellular developmental stages of Hoferellus cyp rini (Doflein, 1898) into the lumen of renal tubules was monitored histologically. In the autumn the trophozoites of H. cyprini transform epithelial cells into a syncytium in certain portions of the renal tubules. In January, after the syncytium becomes degenerated and disrupted, the trophozoites get into the lumen of the tubules, are transformed into coelozoic developmental stages, and colonize the ureter. After the epithelium of the renal tubule is destroyed, from the direction of the intact basement membrane fibrocytes and macrophages enter the lumen and surround the cellular debris and trophozoites stuck there with a connective-tissue capsule of several layers. KEY WORDS. Hoferellus cyprini, development,intracellular and coelozoic stages, hostreaction, kidney, common carp. In a previous paper (MOLNÁR, CSABA and KOVÁCS-GAYER, 1986) we reported our investigations confirming the statement made by PLEHN (1924), i.e. that Hoferellus cyprini (Doflein, 1898) is a parasite whose development follows a one-year cycle. Its early developmental stages are present in the epithelium of the renal tubules of the common carp (Çy_prinujs_carpio) in the autumn: the trophozoites are located intracellularly in a circumscribed area. During the winter, the parasites gradually get into the lumen of the renal tubules where they develop further as coelozoic Plasmodia up to April when they form spores and leave the host fish. In the opinion of MOLNÁR, CSABA and KOVÁCS-GAYER (1986) in spore morphology H. cyprini is identical with the species Mitraspora cyprini

, and its development is consistent with that found by AHMED (1973) for M. cyprini. MOLNÁR, CSABA and KOVÁCS-GAYER (1986) demonstrated the different developmental stages by regular dissection of fish specimens; however, they could not furnish direct evidence of intracellular developmental stages getting into coelozoic position. In the present paper, studies on disintegration of the so-called Hoferellus nodules and release of intracellular stages into the renal tubules are reported. MATERIALS AND METHODS The test material was obtained from a pond farm situated in Western Hungary. At the end of January 12 two-summer common carp were submitted to our laboratory alive and were dissected within a few days' time. The kidneys and the ureter were removed from the fish in their entirety, together with the urinary bladder. Certain portions of the organs were examin-