Submitted to: International Symposium on Talipia in Aquaculture
Publication Type: Proceedings
Publication Acceptance Date: November 10, 1997
Publication Date: N/A
Interpretive Summary: The most serious infectious disease problem of tilapia producers, worldwide, is cause by Streptococcus, a Gram-positive bacterium. The transmission of this disease occurs fish to fish, especially in closed water fish production facilities. The control of streptococcal disease is difficult and antibiotics are often not effective. The estimated yearly economic loss due to Streptococcus is $150 million, worldwide. More importantly, a Streptococcus species, called S. iniae is emerging as a potential disease of human beings, who suffer from puncture wounds due to handling or cleaning tilapia.
Technical Abstract: Streptococcal disease results in severe losses of fish in intensive culture operations throughout the world, including tilapia and hybrid striped bass in the United States. The organisms responsible are Gram-positive cocci, particularly Streptococcus sp. and Enterococcus sp. These microorganisms are facultative anaerobes (i.e., can grow in the absence of oxygen). This characteristic allows one to presumptively identify these groups (i.e., catalase negative). Recently, much attention has been focused on Streptococcus iniae in North America because of the reported potential for human infection resulting from handling live fish. This publicity resulted from recent cases of S. iniae infection in a single non-US location. Prevention of streptococcal disease may be possible by vaccination of fish. However, at present no commercially licensed vaccines are available. Currently, the best form of control for streptococcal disease is management (i.e., rapid removal of the source of infection or dead and dying fish, water quality management, nutrition and feeding management and breeding of more disease resistant stocks).