The structure and stability of parasite communities have been mainly explained by high diversity and strong interactions among parasite species. During 16 months, 558 Barbus martorelli gill infracommunities were studied in a tropical zone to determine whether parasite infrapopulations interact. Three levels were retained: the infracommunity level, the gill filament level, and the filament fract...

Species of the phylum Myxozoa are common parasites of fish and can cause severe losses in cultured species. Although a number of myxozoan life-cycles have now been elucidated, little is known about the biology of these organisms in the fish host. Monoclonal antibody B4 raised to the myxozoan Tetracapsuloides bryosalmonae has been previously noted to react with a number of species infecting fish...

The core of the theory of absolutely summing operators lie in the ideas of A. Grothendieck in the 1950s. Further work (after a decade) of A. Pietsch [19] and Lindenstrauss and Pe l czyński [9] clarified Grothendiecks insights and nowadays the ideal of absolutely summing operators is a central topic of investigation. For details on absolutely summing operators we refer to the book by Diestel-Jar...

 This study was carried out to investigate occurrence of parasite in selected cyprinid fish species in Gandoman Lagoon, in the vicinity of Gandoman City, Chaharmahal & Bakhtyari Province. A total of 90 fish specimens including Cyprinus carpio, Carassius auratus gibelio, Capoeta aculeata , C.damascina, Chondrostoma regium and Alburnus alburnus from Gandoman were examined during spring and summer...

The spore of Myxosoma cerebralis is redescribed and compared with that of a close relative, M. cartilaginis. M. cerebralis is smaller, with greater variability in size and shape. It possesses a mucous envelope whereas M. cartilaginis does not. The surface architecture of M. cerebralis, as seen with the scanning electron microscope, differs in possessing a conspicuous circumsutural groove, promi...

The aquatic oligochaete Tubifex tubifex is an obligate host of Myxobolus cerebralis, the causative agent of salmonid whirling disease. Tubifex tubifex can become infected by ingesting myxospores of M. cerebralis that have been released into sediments upon death and decomposition of infected salmonids. Infected worms release triactinomyxons into the water column that then infect salmonids. How t...

Salmonid species vary substantially with respect to both susceptibility and pathology when challenged with Myxobolus cerebralis (O’Grodnick 1979). Even within a species, strain differences in susceptibility have been demonstrated (Densmore et al. 2001). Rainbow trout are generally accepted to be one of the most susceptible species to M. cerebralis infection, yet are one of the most popular spor...

The core of the theory of absolutely summing operators lie in the ideas of A. Grothendieck in the 1950s. Further work (after a decade) of A. Pietsch [21] and Lindenstrauss and Pe lczyński [11] clarified Grothendiecks insights and nowadays the ideal of absolutely summing operators is a central topic of investigation. A natural question is how to extend the concept of absolutely summing operators...