ABSTRACT: The progression of channel catfish virus (CCV) and thymidine kinase negative recombinant CCV (CCVTK^-) infections in immersion challenged channel catfish Ictalurus punctatus fingerlings was studied by plaque assay and quantitative polymerase chain reaction (QT-PCR). Infectious CCV was isolated from Day 2 through Day 8 in skin and blood and through Day 10 PI in posterior kidney and gills. Infectious CCVTK^- was detected from Day 2 through Day 6 PI in skin and blood and through Day 8 PI in posterior kidney and gills. The kinetics of both infections were similar until Day 5 PI, after which virus concentrations were higher in CCV infected fish than in those exposed to CCVTK^-. Both viruses were detected in water; however, the CCV concentration was higher than CCVTK^- during all time periods and was detected on Days 2 through 5 PI, whereas CCVTK^- was detected on Days 3 through 5 PI. The QT-PCR showed higher amounts of viral DNA in the skin and water at early and late periods in infection in CCV challenged groups as opposed to CCVTK^- groups. This study indicates that the kinetics of CCV and CCVTK^- infections are similar but CCVTK^- infections do not persist as long and have reduced shedding ability.

KEY WORDS: Ictalurid herpesvirus 1 · Quantitative PCR · Thymidine kinase · Vaccines · Ictalurus punctatus

Published in DAO Vol. 27, No. 1 (1996) on October 17
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1996