Epizootiology and histopathology of Parvicapsula sp. in @entity2322 XXXX .

@entity281 @entity32 @entity2322 @entity39
The epizootiology and histopathology of the myxosporean Parvicapsula sp. was studied during monthly health surveys of 4 groups of @entity2322 @entity2322 at a commercial farm in Puget Sound, Washington, USA, from 1984 to 1986. No Parvicapsula sp. was detected in histological samples taken from juvenile fish in fresh water, but the parasite was detected in fish from all groups 2 to 8 mo after transfer to seawater net pens. Groups placed in seawater net pens in November and December had a higher prevalence of @entity281 , and a longer period of continuous detected @entity281 , than those introduced into net pens in May. For the groups transferred to seawater in November and December, the highest @entity281 prevalence (45 to 90%) was detected during the following March and April. Among 13 tissues examined histologically, only the pseudobranch and kidney were positive for Parvicapsula sp., with 26 (62%) of 42 positive fish showing @entity281 only in the pseudobranch, 5 (12%) showing @entity281 only in the kidney, and 11 (26%) showing @entity281 in both organs. Both the pseudobranch and kidney were apparent primary @entity281 sites, but @entity281 appeared to persist longer in a population. @entity281 were frequently heavy and associated with extensive @entity32 and @entity39 of filament and lamellar tissues. The kidney had been the only @entity281 site reported for Parvicapsula sp. in previous studies of @entity2322 .
