Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2002
Publication Date: October 28, 2002
Citation: Klesius, P.H., Evans, J.J., Shoemaker, C.A. 2002. Control and prevention of Streptococcus in fishes by vaccination [abstract]. 7th Brazilian Meeting of Pathologists of Aquatic Organisms and 3rd Latin American Meeting of Pathologists of Aquatic Organisms. p. 397-409. Technical Abstract: The gram-positive coccus, Streptococcus iniae, is among the most prominent causes of streptococcosis in both cultured and wild fish. This cossus is highly virulent and rapidly transmitted between fish of the same or different species. Global movements of fish and their pathogens have helped to spread streptococcosis into regions that were previously unaffected. Stressed fish are most susceptible to infection and rapidly succumb to disease within 24 to 72 hours after infection. Streptococcosis fits our disease continuum model where the fish immune system is weakened due to interactions between the neuro and immune systems in response to stressors. Transmission is horizontal where morbid fish are cannibalized by the large numbers of non-infected fish. The major routes of infection are inhalation and/or ingestion. Resistance to antibiotics, refusal of sick fish to eat mediated feed, and the rapid onset of mortality make antibiotic therapies inadequate. Vaccination is the best means of preventing streptococcosis when integrated into a biosecurity plan. A vaccine against S. iniae has been successfully developed and employed in fish production systems. This vaccine is a modified bacterin administered by injection. However, bath immersion vaccination is being tested. Fish biosecurity calls for the management of husbandry and environmental stress, prevention of infection by vaccination, quarantine of new arrivals, health and water quality monitoring, and disinfection of facilities and equipment on an as used basis. Adoption of such a biosecurity plan is a much more cost-effective alternative to depopulating and fallowing a highly infected production facility.