Abstract
In November 2011, the renal sphaerosporosis was found in cage-cultured orange-spotted grouper Epinephelus coioides in a fish farm in Guangdong, China. The infected fish exhibited emaciation, anaemia, anorexia, renomegaly, slight splenomegaly, and occasionally skin ulcer. The cumulative mortality reached at 50% to 80% within 2 weeks, when water temperature ranged from 21°C to 27°C. The renal tubules were almost completely occluded by sporogonic pseudoplasmodia of a myxosporean, and mature spores were found in the lumen. Combined with morphological, histopathological, and molecular analyses, Sphaerospora epinepheli was suggested as the etiological agent. This is the first report of mortality case of cultured E. coioides associated with S. epinepheli.
