Myxosoma cerebralis: Detection of circulating antibodies in infected rainbow trout (Salmo gairdneri)

Circulating antibody against spores of Myxosoma cerebralis has been detected for the first time in rainbow trout (Salmo gairdneri) affected with whirling disease. An indirect fluorescent antibody test (IFAT) was employed for detection of trout immunoglobulin. Most sera of fish from an infected experimental group were found to give a positive reaction in the IFAT, while the majority of specific-pathogen-free control sera gave no reaction. Reagent preparation as well as staining and evaluation procedures are given. These results provide additional information for understanding the host/parasite relationship and offer a potential for development of a nondestructive serological test for whirling disease.