Submitted to: International Conference on Recirculating Aquaculture
Publication Type: Proceedings
Publication Acceptance Date: 4/27/2004
Publication Date: 7/22/2004
Citation: Shoemaker, C.A., Klesius, P.H., Evans, J.J. 2004. Prevalence of and vaccination against Streptococcus iniae. Proceedings of 5th International Conference on Recirculating Aquaculture. p. 86-94.
Technical Abstract: Streptococcus iniae is a Gram-positive coccus shaped bacteria that is responsible for causing streptococcal disease in farmed and wild fish worldwide (Shoemaker et al. 2000a). From 1995-1996 reports of S. iniae in humans resulted in an increased awareness of this disease of farmed fish (Weinstein et al. 1997). The cases in Canada were supposedly caused by the same clone (based on pulsed field gel electrophoresis) of S. iniae and believed to be a result of preparing live tilapia for consumption that had been raised in the United States. These reports prompted a national assessment of tilapia and hybrid striped bass farms to determine the prevalence of S. iniae in the United States by the Agricultural Research Service (Shoemaker et al. 2001). Recently, two cases of invasive S. iniae were reported in China (Lau et al. 2003). Lau et al. (2003) determined that the isolates were genetically unrelated to the isolates implicated in the Canadian cases. However, there were similarities in the cases from China and Canada in that all patients were elderly and of Asian decent. Effective control strategies are needed to eliminate this disease from cultured fish to reduce the effect on the fish (i.e., depressed growth and mortality) and to deter any further human cases and negative publicity that may be a result of implicating farm raised fish. Strategies to control this important pathogen have included antibiotic treatments (Stoffgren et al. 1996) and development of vaccines against S. iniae that were shown to be efficacious in tilapia and hybrid striped bass (Klesius et al. 1999; Klesius et al. 2000; Shelby et al. 2004). This chapter will discuss in detail the prevalence of S. iniae determined in healthy fish and will describe the methods currently available for vaccinating fish against S. iniae.