Streptococciasis Disease
Cause: Streptococcus agalactiae, S. iniae,
Bio - Ecology of pathogens:
• gram-positive bacteria, small round (cocci), joined
chain-like, non-motile, transparent and smooth colonies.
• Streptococcus iniae Infection often occurs in sea water fish farming (snapper, grouper), whereas S. agalactiae is more commonly found in freshwater fish farming (tilapia).
• The pattern of attacks are generally two types of bacteria are chronic - acute.
• Target organs of infection of Streptococcus spp. commonly found in the brain and eyes. so-called "syndrome, meningoencephalitis and panophthalmitis". The disease is frequently reported in intensive aquaculture systems, aquatic environment calm (stagnant) and / or recirculation systems,
• Cumulatively, the attack of this disease can cause mortality of 30-100% of the total population during the maintenance period: and this disease is a potential obstacle that must be anticipated with respect to intensification and improvement of national tilapia production.
Clinical Symptoms:
• Indicates abnormal behavior such as convulsions or spinning and prominent eyes (exopthalmus).
• decreased appetite, weakness, dark-colored body, and slow growth.
• Dark colors under the jaw, prominent eyes, bleeding, abdominal bloat (dropsy) or injuries that develop into ulcers.
• Occasionally. do not show obvious clinical symptoms except death continues.
• no directional movement (nervous) and bleeding on the gill cover (operculum).
• Often, too, found that the infected fish appear normal until shortly before death.
Diagnosis
• Isolation and identification of bacteria through bio-chemical tests.
• Detection of bacterial genes by polymerase chain reaction (PCR)
Control:
• Disinfection of aquaculture facilities before and during the maintenance of fish
• Prevention of early (seed) through vaccination anti-Streptococcus spp.
• Giving immunostimulan element (eg addition of
vitamin C in feed) are routinely during maintenance
• Improve overall water quality, particularly reducing the levels of dissolved organic material and / or increase the frequency of replacement of new water
• Management of fish health in an integrated (fish, environment and pathogens)
source: Ministry of Maritime Affairs and Fisheries of Indonesia, Directorate General of Aquaculture, Fish and Environmental Health Directorate, 2010
