ARS | Publication request: Streptococcus iniae vaccine

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2009
Publication Date: March 10, 2010
Citation: Klesius, P.H., Pridgeon, Y.W., Shoemaker, C.A. 2010. Streptococcus iniae vaccine. In: Proceedings of BIT Life Sciences' 2nd World Vaccine Congress - 2010. March 24-26, 2010, Beijing, China. p. 307.

Technical Abstract: Streptococcus iniae is among the most important emergent pathogens that affects many fish species worldwide, especially in warm-water regions. In marine and freshwater systems, this Gram-positive bacterium causes significant economic losses, estimated at hundreds of millions of dollars annually. Infection results in septicemia and neurotropic disease, with cumulative percent mortality between 30 to 50%. Streptococcal disease is very difficult to control because this pathogen is resistant or become resistant to most antibiotics. Also, S. iniae is considered to be infectious for humans. The aim of this paper is to provide current information on a modified killed S. iniae vaccine for the prevention of streptococcosis in tilapia and other species of cultured fish. This vaccine was demonstrated to protect against heterogeneous S. iniae isolates with RPS of 80% or greater. Serum antibody against S. iniae was demonstrated to be responsible for protective immunity by passive transfer. Head kidney tissues were sampled to identify immune response genes upregulated immediately following vaccination. The duration of the protective immune response was found to range from 6 to 8 months without an adjuvant. Experimental challenge of cohabitated vaccinates and sham-vaccinates (calcein marked) were used to evaluate vaccine efficacy.