Submitted to: Annual Eastern Fish Health Workshop
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 1999
Publication Date: March 8, 1999
Citation: SHOEMAKER, C.A., EVANS, J.J., KLESIUS, P.H. EFFICACY OF A KILLED STREPTOCOCCUS INIAE VACCINE. 24th ANNUAL EASTERN FISH HEALTH WORKSHOP. 1999. Technical Abstract: Streptococcus iniae, which causes streptococcal disease in tilapia (Oreochromis niloticus) and hybrid striped bass (Morone saxatilis X M. chrysops), is the most important disease agent in water re-use aquaculture systems in the United States. An effective vaccine to S. iniae is desirable and would help reduce the economic loss caused by this bacterium. We have produced a killed toxoid enriched S. iniae vaccine containing whole cells and concentrated extracellular products (greater than 2 kDa). The vaccine was administered to tilapia (mean weights of 25 and 100g) by intraperitoneal (IP) injection. At 26-30 days post vaccination, the groups of vaccinates and non-vaccinates were IP challenged with S. iniae (1 X 108 CFU) and monitored daily for clinical signs and mortality. Vaccination reduced mortality and prevented erratic swimming, hemorrhagic exopthalmia and ocular opacity. Non-vaccinates began dying 1 day post challenge from S. iniae infection. Clinical signs began occuring on day 4-5 post challenge with peak mortality occuring at about the same time. Vaccine administered by IP injection resulted in RPS values of 84 to 100. These results show that the development of an effective S. iniae vaccine for use in tilapia is possible. The intramuscular route of immunization is currently underway to determine the optimal route of vaccination by injection.