ARS | Publication request: EFFICACY OF A KILLED STREPTOCOCCUS INIAE VACCINE IN TILAPIA (OREOCHROMIS NILOTICUS)

Submitted to: European Association of Fish Pathologists
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 1999
Publication Date: N/A

Interpretive Summary: A vaccine against Streptococcus iniae, an emerging bacterial disease of cultured fish worldwide, was developed and shown to prevent this disease in tilapia. The vaccine worked in small and large tilapia. Streptococcus iniae is a major disease of tilapia, hybrid striped bass and trout and has been associated with infections of humans who have been skin punctured by fins of live highly infected tilapia in Canada. The use of this vaccine i estimated to save producers of these cultured fish about 100 million dollars annually, worldwide. Research is ongoing to test the effectiveness of the vaccine by both injection and bath immersion immunization routes in tilapia and hybrid bass.

Technical Abstract: Tilapia (Oreochromis niloticus) were vaccinated intraperitoneally (IP) at mean weights of 25 and 100 g with killed Streptococcus iniae vaccine composed of whole cells and concentrated, extracellular products (greater than 2kDa). At 30 days post vaccination, the groups of vaccinates and non-vaccinates were IP challenged and monitored daily for clinical signs and mortality for 60 days. Vaccination reduced mortality 91.3 percent and prevented erratic swimming, hemorrhagic exophtalmia and ocular opacity. Immunized 25 g tilapia had relative percent survival (RPS) of 95.3 and 100 g tilapia had RPS's ranging from 84.2 to 94.7.