DAO 39:143-146 (2000)  -  doi:10.3354/dao039143

Preliminary description of lesions in juvenile largemouth bass injected with largemouth bass virus

Dina Zilberg*, John M. Grizzle, John A. Plumb**

Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, Alabama 36849, USA
*Present address: University of Tasmania, Department of Aquaculture, PO Box 1214, Launceston, Tasmania 7250, Australia **Corresponding author. E-mail:

ABSTRACT: Juvenile largemouth bass Micropterus salmoides were intraperitoneally injected with largemouth bass virus (LMBV), a member of the genus Ranavirus, family Iridoviridae. Moribund fish which had been injected with 106.2 tissue culture infectious doses, 50% endpoint (TCID50), were sampled 4 d after injection; other largemouth bass injected with this dose died between 3 and 5 d after injection. Fish injected with 102.8 TCID50 of LMBV were also examined after 4 d and had lesions similar to those of fish injected with the high dose. Clinical signs included darker pigmentation, inflammation and necrosis at the site of injection, distended abdomen, corkscrew swimming, and lateral recumbency. Internally, fish had focally pale livers, bright red spleens and reddened intestinal ceca. Histologically acute fibrinous peritonitis affected the surface of all organs in the peritoneal cavity, but deeper portions of organs appeared normal. There was also necrosis of the gastrointestinal mucosa. Except for the injection site, lesions were confined to the peritoneal cavity.

KEY WORDS: Fish virus · Histopathology · Iridoviridae · Ranavirus

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