Document Type



Flexibacter columnaris, walleye, Stizostedion vitreum vitreum, bacterial diseases


The role of mechanical injury in transmission of Flexibacter columnaris to walleye fingerlings (Stizostedion vitreum vitreum) was investigated. Two groups (1 and 2) of 10 fish each, 7 to 9 cm total length, were exposed to a suspension of F lexibacter columnaris containing 3 X 105 cfu/ mL; fish in group 1 were injured with a scratch along their flank; fish in group 2 were not injured. Two control groups (3 and 4) of 5 fish each were exposed to a sterile broth; group 3 was injured with a scratch and group 4 was not. In 72 h, morbidity was obvious in 7 of 10 fish in group 1, 1 of 10 in group 2, but none of the controls (groups 3 and 4). F. columnaris was isolated on cytophaga agar from swabs taken from moribund fish in groups 1 and 2, but not from healthy fish in any groups. In moribund fish, of group 1, F. columnaris was isolated from skin lesions of all 7 fish, from the gills of 2 fish, and from the kidney of 1 fish. Tissue damage in moribund fish in group 1 included extensive necrosis of the skin and underlying musculature; gill damage included epithelial separation, infarcts, and, in the most severe case, a secondary fungal infection. The inflammatory response included a substantial increase in relative abundance of lymphocytes in infected fish compared with healthy fish. In a plate culture, antibiotic sensitivity test, oxytetracycline was the most effective among the seven antibacterials examined.

Publication Date

June 1991

Journal Title

Journal of the Iowa Academy of Science





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© Copyright 1991 by the Iowa Academy of Science, Inc.



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