Efficacy of a modified live Edwardsiella ictaluri vaccine in channel catfish as young as seven days post hatch

Channel catfish (Ictalurus punctatus) were vaccinated by immersion at 12, 1 4, 16 and 31 days post hatch with modified live Edwardsiella ictaluri RE-33 vaccine in 1997 and 7 and 10 days post hatch in 1998. At 20 to 21 days pos t vaccination, the groups of vaccinates and non-vaccinates were challenged with virulent E. ictaluri and monitored for mortality for at least 14 days following challenge. Results showed the vaccine to be efficacious in channe l catfish as young as 7 days post hatch with relative percent survival rang ing from 58.4 to 77.5. (C) 1999 Elsevier Science B.V. All rights reserved.