ABSTRACT: A Cryptobia salmositica DNA probe (Cs-V1), of approximately 1.2 kilo base-pairs (kb), was developed from an avirulent strain of the pathogen. Nuclear DNA of C. salmositica was isolated, cleaved with HindIII, cloned, and labelled with non-radioactive digoxigenin. Cs-V1 hybridized specifically with C. salmositica DNA and there were no cross-hybridizations between the probe and DNA from C. borreli, C. bullocki and C. catostomi. A potentially useful identification/diagnostic technique for C. salmositica was developed using blood dried on filter paper. The dried blood DNA dot blot (DBDB) technique distinguished C. salmositica from C. catostomi, C. bullocki and C. borreli and it was also used for the diagnosis of C. salmositica infection in fish. The technique does not require DNA purification and the probe does not cross-hybridize with rainbow trout blood DNA. Less than 20 ul of fish blood (which contains approximately 100000 organisms ml^-1) is required using the DBDB technique.

KEY WORDS: Cryptobia salmositica . DNA probe . Cryptobiosis . Diagnosis . Rainbow trout

Published in DAO Vol. 25, No. 1-2 (1996) on May 9
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1996