Amoebae were found to cause severe gill tissue damage in turbot, Scophthalmus maximus L. from a grow-out facility in northwestern Galicia (Spain). The nature and extent of lesions along with negative results of bacteriological and virological examination made this agent responsible for mortalities in four turbot stocks supplied with water from a single source. We present our findings, although we failed to isolate amoebae, since there was a clear evidence of their primary role in the development of disease condition and occurrence of mortalities. In addition, this is a record both of a new host endangered by amoebae in intensive cultures and pathogenesis of the gill lesions.
Three new myxosporean species are described from Tetraodon fluviatilis (Osteichthyes: Tetraodontidae) imported from Southeast Asia to the Czech Republic. Zschokkella tetrafluvi sp. n. lives in the gall bladder. Di- or monosporic plasmodia produce ellipsoidal spores averaging 11.3 x 7.2 pm. Zschokkella pleomorpha sp. n. infects renal tubules and renal corpuscles; mono- to polysporic plasmodia produce spores averaging 15.7 x 7.1 pm. In the process of maturation, immature subspherical spores assume elongated shape. In both species, extremely curved suture line does not bisect poles of the spore. Ortholinea tetrafluvi sp. n. occurs as a rule in mixed infections with Z. pleomorpha sp. n. in the renal tubules. Mono- to polysporic plasmodia produce spores with a wide anterior and a narrow posterior end, averaging 8.3 x 7.8 pm. Both Z. pleomorpha sp. n. and O. tetrafluvi sp. n. have also limited number of stages located within the renal tubule epithelium, where they can complete sporogony. In one of the fish specimens, a myxosporean tentatively identified with Sinuolinea tetraodoni El-Matbou)i et Hoffmann, 1994 was found. A new genus is proposed for Ortholinea alata Kent et Moser, 1990 - Kentmoseria gen. n., and its diagnosis is presented.