In her opening remarks, Palma Jordan, marketing director for Aquatic Animal Health Business Unit at Intervet/Schering-Plough Animal Health, said: "Rapid growth and intensified production in the aquaculture industry are presenting producers with streptococcal disease challenges that threaten their stock with significant morbidity and mortality. Some Streptococcus species in aquaculture are familiar pathogens, but others are emerging."
The purpose of the symposium, held in Veracruz, Mexico, in conjunction with World Aquaculture 2009, was to help fish producers and their veterinarians manage the bacterial disease and meet the growing demand for farmed fish — without compromising food safety or the environment, Ms Jordan added.
The symposium started with presentations by Robin Wardle, director, technical services in the United Kingdom, and Neil Wendover, technical service manager Asia-Pacific, Intervet/Schering- Plough Animal Health, who discussed the unexpected complexities of controlling streptococcosis and the importance of taking an integrated approach to tilapia health in complex commercial systems.
In addition, Mr Wardle and Mr Wendover reviewed Intervet/Schering-Plough Animal Health’s efforts to identify the biotype of nearly 500 streptococcal isolates gathered from approximately 50 sites in 13 countries. From the company's sampling, Streptococcus agalactiae Biotype 2 was found to be the most prevalent and geographically diverse of the streptococcal pathogens.
In a later presentation, Mr Wendover also reviewed performance data for Aquavac Strep Sa, a new vaccine developed by Intervet/Schering-Plough Animal Health to control S. agalactiae Biotype 2 infections in farmed tilapia. In the field, vaccination with Aquavac Strep Sa resulted in significantly increased survival and improved feed conversion compared to unvaccinated control fish.
Dr Gina Conroy, fishery biologist with Pharma-Fish SRL in Venezuela, reviewed the prevalence and pathology of streptococcus species in Latin America. She reported that streptococcosis is an important bacterial disease that can lead to high mortality or make fillets unsuitable for trade.
Mark Gaikowski, branch chief for the Aquatic Ecosystem Health Branch, US Geological Survey, Wisconsin, reported on his work demonstrating that Aquaflor (florfenicol), a broad-spectrum, in-feed antibiotic developed for aquaculture, is effective in the field for controlling mortality caused by Streptococcus iniae in tilapia.
In trials conducted at five commercial tilapia farms in the United States with presumed S. iniae outbreaks, Aquaflor resulted in significantly reduced mortality compared to controls. He also reported that mortality in treated fish was reduced more than 80 percent during the 21-day period after dosing.
Dr Richard G. Endris, aquaculture research programme manager for Intervet/Schering-Plough Animal Health, reviewed practical considerations for diagnosing S. iniae infections in hybrid striped bass and the use of Aquaflor to control mortality in commercial operations. The presentation was given on behalf of Dr Vaughn Ostland, former director of aquatic pathology at Kent SeaTech Corporation, California.
Proceedings Available from Streptococcus Symposium
THE NETHERLANDS - Proceedings from a recent symposium that offered integrated health solutions for managing rising streptococcus infections in warmwater fish are now available from the event's sponsor, Intervet/Schering-Plough Animal Health (ISPAH).
