Modifications of Some Histochemical Techniques Used in the Diagnosis of Fish Diseases: Four Case History Reports on Three Pacific Salmonids

Abstract

Clinical and histopathologic findings associated with four diseases in three species of Pacific salmon are described: (1) saprolegniasis in sockeye salmon (Oncorhynchus nerka Walbaum); (2) infection of Chinook salmon (Oncorhynchus tshawytscha Walbaum) by the fungus Phoma herbarum Westend; (3) an unusual case of coldwater disease in coho salmon (Oncorhynchus kisutch Walbaum); and (4) Loma sp. Morrison (Microsporea) infection in chinook salmon. Histochemical techniques with modifications and the importance of histochemistry in supporting the diagnoses are discussed.