Acute Catarrhal Enteritis of Salmonid Fingerlings

For many years, a disease especially of the Eastern speckled trout, Salvelinus fontinalis, variously described as “whirling sickness” or “octomitiasis” has been experienced in almost all trout-rearing establishments. Due to a relative freedom from the parasitic infection, Octomitus salmonis, in the hatcheries of the Maritime Provinces, it has been possible to determine the importance of “enteritis” as a factor in the heavy mortalities of the young salmonid fishes in hatcheries. This interpretation explains several of the anomalies previously reported in “whirling sickness.” The most characteristic phenomenon of this disease is the large quantity of clear mucus (not stained by bile) present in the upper gut. In the Maritime hatcheries, such fish as have been found harboring Octomitus salmonis have been healthy.