Document Type

Article

Department/Program

Virginia Institute of Marine Science

Publication Date

2-1-1996

Journal

Diseases of Aquatic Organisms

Volume

24

Issue

2

First Page

107

Last Page

115

Abstract

We report the histopathological changes occurring in the renal and splenic haemopoietic tissues of coho salmon Oncorhynchus kisutch experimentally infected with renibacterium salmoninarum. In both tissues we were able by light microscopy to distinguish 3 different grades in the progression of the infection. The grades of infection were characterized according to the location of the bacteria and the tissue injuries. Ultrastructural observation revealed sinusoidal cells, macrophages, reticular and barrier cells to be infected by the pathogen, and necrosis of the tissue to be general in advanced stages of the infection. Despite destruction of the haemopoietic tissue, plasmacytopoietic foci were frequently observed in both organs. Other major changes were the appearance of epithelioid cells and an increase in the number of barrier cells. These 2 cell types might be involved in the local defence response to the pathogen, but they may also act as a reservoir and proliferation locus for R. salmoninarum.

DOI

doli: 10.3354/dao024107

Keywords

histopathology; haemopoietic tissue; kidney; spleen; Oncorhynchus kisutch; fish

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