The heart often displayed
an invasion of mononuclear inflammatory
cells, mainly consisting of macrophages. Within the
kidney, the tubular epithelial cells displayed
evidence of cloudy swelling and
hyaline droplet degeneration. The main
pathological finding was severe acute
suppurative meningitis and ventriculitis
present in all moribund fish. Bacterialaden
proteinaeous fluid surrounded by
an inflammatory exudate was present
within the brain of infected fish and signified
the possibility of cranial oedema.
No histopathological findings were observed
in the controls.