|SREL Reprint #0622|
of Red-sore Disease (Aeromonas hydrophila) in Naturally and
Experimentally Infected Largemouth Bass Micropterus salmoides (Lacepede)
W. Huizinga, G. W. Esch and T. C. Hazen
The histophathology of red-sore disease, caused by
the gram-negative bacterium, Aeromonas hydrophila, is described
for largemouth bass, Micropterus salmoides.
Externally, lesions range from those affecting a few scales (pin-point),
to those associated with extensive chronic ulcerations; there is focal
hemorrhage, oedema and dermal necrosis which exposes underlying muscles
producing infiltration of mononuclear and granulocytic inflammatory cells.
Internally, the liver and kidneys are foci for toxic products produced by
A. hydrophila with, in the most severe cases, complete destruction
of the structural integrity of both organs.
Pathological changes were not serious in either the spleen or heart, even
in cases with massive damage in the liver and kidney.
Internal and external lesions were similar in both natural and
experimentally induced infections. The
pathobiology of red-sore disease in bass is postulated to be linked to elevated
water temperature stimulating increased metabolism, decreased body condition and
stress, leading to the increased production of corticosteriods and the
concomitant rise in susceptibility to infection.
SREL Reprint #0622
Huizinga, H.W., G.W. Esch, and T.C. Hazen. 1979.
Histopathology of red sore disease (Aeromonas hydrophila) in
naturally and experimentally infected largemouth bass
Micropterus salmoides (Laceped). Journal of Fish Diseases