Development and use of modified live Edwardsiella ictaluri vaccine against enteric septicemia of catfish.

The present study showed that E. ictaluri RE-33 vaccine does not cause ESC but does stimulate protective immunity. The RE-33 vaccinates were protected against ESC for at least 4 months following a single bath immersion in a low number of E. ictaluri RE-33 without booster vaccination. Antibody responses are weak after RE-33 vaccination. Edwardsiella ictaluri RE-33 vaccine presents no risk or hazard to catfish. RE-33 vaccine will prevent ESC caused by most isolates of E. ictaluri in catfish. We recently obtained from USDA, Animal Plant Health Inspection Service (APHIS), and the state veterinarians of Alabama and Mississippi, approval to field test the RE-33 vaccine in young catfish. About 2-3 million 10- to 30-day-old channel catfish in Alabama and Mississippi have been vaccinated since June 1997 with no adverse effects of vaccination.