An unidentified epi-epithelial myxosporean in the intestine of gilthead sea bream Sparus aurata L.

Abstract

In the course of experimental infections of gilthead sea bream Sparus aurata with the myxozoan Enteromyxum leei, stages of an unidentified myxozoan were observed attached to the intestinal brush border of some fish. Infection levels of the parasite, which was named "epi-epithelial myxosporean" (EEM) were recorded, and its structure was studied by light microscopy (LM) and electron microscopy (EM). In situ hybridisation (ISH) probes specific for E. leei were developed and used to differentiate between the two parasites. The EEM parasite was observed only in epi-epithelial position on the intestine mucosa and never in any of the other tissues studied (kidney and gall bladder). Prevalence was variable, with values reaching 40.2%. With transmission EM, trophozoites displayed pseudopodia-like projections inserted in between the enterocyte microvilli, producing an intimate interface. No mucosal histopathology that could be attributed to the myxozoan was found. EEM stages did not stain with the E. leei-specific ISH probes. From the results of the LM, EM and ISH studies, we conclude that the EEM parasite found in gilthead sea bream intestine in both Mediterranean and Red Sea sites is a coelozoic myxosporean, distinct from E. leei.

3D Morphology, Ultrastructure and Development of Ceratomyxa puntazzi Stages: First Insights into the Mechanisms of Motility and Budding in the Myxozoa

“…have been described to possess cytoplasmic extensions [26], [34]–[35]. However, they have been related predominantly to anchorage in the host epithelium and to a potential increase in the absorptive surface which is in contact with host cells [36]–[39]. In myxozoans, pinocytosis has been observed as a means of energy transfer from host to parasite, with the P cell taking up material from the surrounding host cell, but also from P cells to S cells [40].…”

Myxobolus turpisrotundus (Myxosporea: Bivalvulida) spores with caudal appendages: investigating the validity of the genus Henneguya with morphological and molecular evidence

“…Myxosporean parasites have a significant role as pathogens of freshwater and marine fishes in wild and cultured stocks with over 2,180 described species (Lom and Dyková 2006;Cuadrado et al 2007;Al Quraishy et al 2008). Most species are identified on the basis of the myxospore (Lom and Arthur 1989;Eiras et al 2009;Molnár et al 2009).…”

Some additional data to the occurrence, morphology and validity of Myxobolus turpisrotundus Zhang, 2009 (Myxozoa: Myxosporea)

“…Myxosporea Bütschli, 1881, are mainly fish parasites with over 2,180 described species (Munoz et al 2000;Ali et al 2002;Lom and Dyková 2006;Cuadrado et al 2007;Al Quraishy et al 2008). Among the myxosporea, species of the genus Myxobolus Bütschli, 1882, are most commonly found in fish, with 744 known species throughout the world (Eiras et al 2005).…”