Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: July 6, 2004
Publication Date: August 14, 2006
Citation: Klesius, P.H., Evans, J.J., Shoemaker, C.A., Pasnik, D.J. 2006. Streptococcal vaccinology in aquaculture. Book Chapter in Tilapia Biology, Culture, and Nutrition. Chhorn E. Lim and Carl D. Webster editors. Food Products Press an imprint of The Haworth Press Inc.,Binghamton, New York. Chapter 17 p. 583-606. Technical Abstract: Minimizing the effects of diseases is crucial to prevent morbidity and mortality and to promote optimal growth of farmed tilapia in fresh and marine waters. Since the inception of aquaculture, the control of diseases has been dependent on the use of therapeutics. The resolute demands of consumer, environmental and governmental groups for wholesome fish and for an environment free of potentially harmful drugs in aquaculture production have increased. In addition, issues related to increased emergence of antibiotic resistant pathogens have made headlines and stimulated serious public concern. World tilapia production was 1,374,239 metric tons in 2002 http://ag.arizona.edu/azaqua/ista/markets.htm). Currently, tilapia ranks third in the world among the species of farmed fish produced, and it is predicted that tilapia will become the most important aquaculture crop this century. The worldwide farm value of tilapia was $1,706,538,200 in 2000 (http://ag.arizona.edu/azaqua/ista/markets.htm). The continued growth and well-being of tilapia aquaculture requires that the industry meet the challenges of minimizing the effects of disease, providing a wholesome product, and preventing increases in pathogen resistance to antibiotics and chemotherapeutics. The tilapia industry can meet these challenges with more rapid and expanded health management practices that make use of vaccines to increase the survival and optimal growth of farmed tilapia. Vaccination is among the most successful veterinary practices to prevent deaths and to provide safeguards for animal production and biosecurity (Klesius et al., 2000a, b; Klesius et al., 2001). In recent years, fish vaccinology has made real progress in both the safety and efficacy of vaccines, especially against bacterial diseases of salmonids (Gudding et al., 1997). Fish vaccines that are currently available for immunization of fish may be found on the http://www.aphis.usda.gov website. However, very limited information is available in the literature on tilapia vaccination. One of the earliest studies showed that Nile tilapia (Oreochromis niloticus) vaccinated intraperitoneally (IP) with a killed Aeromonas hydrophila vaccine were protected against infection (Rungpan et al., 1986). The formalin-killed bacterin provided 53-61% protection one week after immunization and 100% protection two weeks after immunization. This study demonstrated that vaccination could prove a useful and effective tool for tilapia aquaculture. Tilapia are widely cultured throughout the world, though multiple factors affect their successful aquaculture production. One of the major issues is streptococcal disease, caused by a variety of Streptococcus spp. that produce significant mortalities among farmed tilapia worldwide. Tilapia growers consider streptococcal diseases caused by S. iniae and S. agalactiae the most serious economic threat to profit loss (Klesius et al., 2000a; Shoemaker et al., 2000; Shoemaker et al., 2001a; Evans et al., 2002). Streptococcus agalactiae infection is responsible for severe economic losses in seabream and tilapia production (Evans et al., 2002; Glibert et al., 2002). In addition, seabream, seabass, yellowtail, amberjack, and rainbow trout producers suffer severe economic losses due to Lactococcus garviae infection (Kitao, 1993; Eldar et al., 1996, 1999; Schmidtke and Carson, 1999). Losses to all of these bacterial pathogens are estimated in the millions of dollars annually, worldwide.