Sea bass Dicentrarchus
labrax nervous necrosis virus isolates with distinct pathogenicity to
sea bass larvae
G. Breuil, O. Mouchel, C.
Fauvel, J. F. Pepin-2001
Diseases of Aquatic Organisms, 45(1) : 25-31
Abstract:
Reproduction of nodavirus disease was performed by
experimental infection of sea bass eggs during fertilization or at larval
stage 4 with 2 genetically distinguishable nodavirus strains (Sb1 and Sb2)
isolated from sea bass collected along the Atlantic and Mediterranean French
coast. The pathogenicity of the virus strains was assigned after detection
of the virus by ELISA and immunohistochemistry (IHC). The Atlantic (Sb1)
strain was more pathogenic than the Mediterranean (Sb2) strain during the
fertilization step whilst both strains were pathogenic following
experimental exposure of 4 d old larvae. Virus lesions developed in the
brain 4 to 6 d following experimental exposure. Experimental ELISA proved
very sensitive for detecting the nodavirus in Sb1 or Sb2 experimentally
infected larvae, as well as in naturally infected sea bass larvae collected
in French hatcheries or in barramundi larvae reared in the Pacific area. The
development of an ELISA specific for the 2 nodavirus strains isolated from
the sea bass should be useful for the detection of the virus, in addition to
other techniques recommended by the Office International des Epizooties
(OIE).
(Laboratoire de Recherche
Aquacole, IFREMER, 34250 Palavas-les-Flots, France, E-mail: gbreuil@ifremer.fr)